PPI - Checklist please
12-19-2007, 03:06 PM
#1
Drifting
Thread Starter
PPI - Checklist please
Hey Folks,
I'm helping my friend to buy a car and of course I'm having him do a PPI.
Does anyone have a checklist that my friend can give to a shop.. He wants a very thorough and complete inspection and is willing to pay for it.
I want to make sure that the shop he brings it to has a checklist to work off of.
B
I'm helping my friend to buy a car and of course I'm having him do a PPI.
Does anyone have a checklist that my friend can give to a shop.. He wants a very thorough and complete inspection and is willing to pay for it.
I want to make sure that the shop he brings it to has a checklist to work off of.
B
12-19-2007, 03:19 PM
#2
Burning Brakes
Join Date: Oct 2006
Location: Ann Arbor, MI
Posts: 901
Likes: 0
Received 0 Likes
on
0 Posts
I have collected this- you may want to edit it down....
1. Check for Dual Mass Flywheel Transmission noises (rattling, knocking noises at engine start, load shift, during idling or when switching off the engine). If I hear this I need to hand it over to the service folks since test needs to be performed by service department to determine if replacement is needed or if working correctly and noise is related to a different component.
2. Check Oil Pressure. If oil pressure light is on, lack of oil pressure when the engine is first started. Non-return check valve is installed between the oil tank and the engine to prevent tank from emptying into the crankcase when engine is turned off. Modified check valve installed from engine number M96/70-64 1 01282. New part has a light blue paint dot.
3. Check to see if clutch pedal sticks. Clutch pedal may not return to its initial position or may become stuck. The axial motion in the plug-in couplings and the associated rolling of the sealing ring can admit air into the hydraulic system. A snap ring, PN 999 230 685 40, must be fitted and the system.
4. Check if the clutch pedal does not fully reach original position. After pressing the clutch, the clutch pedal is slow to come back up and does not fully reach its original position. This is caused by air in the hydraulic system.
5. Check for noises in the steering. Clicking or grating noises during steering. Grating- This noise occurs when steering movements are made around the center position to full lock position. New stop plate required PN 996 343 107 03. Clicking - This noise occurs shortly before turning the steering wheel to full lock. A loose rod nut causes the noise. The solution is to tighten the strut piston rod fastening nut to the specified torque. Also, a longer piece of hose needs to be installed in the first few turns of the spring to replace shorter one initially in place.
6. Check for loud whistling noise from the engine area . A loud whistling noise can be heard (both inside and outside) from the engine area while driving. The noise is caused by the pressure control valve in the steering oil reservoir. Valve vibrates strongly when hydraulic oil flows through it. Fix is to replace the complete steering oil reservoir with the modified pressure control valve - PN 996 314 920 34
7. Check for noises in the rear seat well. Audible clicking-type noises in the rear seat well due to movements of the transverse reinforcement tube and contact with the rear seat well panel. Fix is to install felt tape between the reinforcement tube and the rear seat well panel.
11. Check the microswitch. Front lid lock issues with micro switch. Micro switch located on the bottom part of the front lid latch may stick causing: the light not to illuminate when the trunk is opened; the light not to go off when the trunk is closed (draining the battery); the alarm horn will sound when locking the car. A new micro switch was installed from the middle of Feb 2000 and can be identified by a yellow or blue paint dot in the micro switch.
8. Check for noises in the door lock area. Catch bar rubbing in the door lock. Fix is to spray silicone lubricant spray in the affected areas (in the inner area of the lock).
9. Check for noises from sunroof frame Movement between the new sunroof frame and the roof causes creaking noises. Fix is to install two strips of Teflon tape and retorque bolts to new specs of 9.7Nm(7.4ft-lb).
10. Check for noises in the Tilting/Sliding sunroof. Muffled rattle from rear area of the tilting/sliding sunroof due to the loss of edge guard for the water drain bracket. When the edge guard is missing, the roof liner can bump into the sliding sunroof frame and cause noises. Fix is to install new edge guard for the water drain bracket.
11. Check rear spoiler operation
12. Check vanity mirror. If it is not working the fix (after validating fuse and light bulb) is to replace the vanity mirror PN 996 731 903 01 01C
13. Check if airbag warning light comes on. If so and it gives: Fault Codes 46 and 49. Fix is to change the seat plug connector and install a new belt buckle (passenger and driver side)
14. Validate that the memory for the seat and mirror work correctly when using the keys. As of model year 2001 if a locked vehicle is opened with the key head remote control, the driver's seat and the door mirror will be set in the position stored in the seat memory. Due to hardware fault, the radio code and the transponder code have been entered in different storage positions in the alarm control unit. Fix is to reprogram all the keys. Spare key is required when doing this.
15. Validate remote control range. If range sucks even after replacing battery the fix is to re-route antenna lead.
16. Check that the VIN matches number on the title and/or other documentation
17. Closely visual inspect the paint. Look closely at every panel. Spend at least 30 seconds per panel. Stand back and look at an entire side of the car. Make sure that the color does not vary (sign of repaint). Check that one wheel is not in better shap than any other (wheel replacement due to accident).
18. Check the tires for wear. Check if all tires are the same brand and type.
19. Check the undercarriage. Look for any scrapes/damage. Ideally put it up on a lift. Look for anything loose or worn. Make sure that the components/wear seems reasonable for the mileage on the car.
20. Check the brake pads and rotors for wear and correct thickness.
21. Check for wheel bearing play.
PRE PURCHASE INSPECTION:
A pre-purchase inspection performed properly by a technician with both product knowledge and a broad experience base can save a prospective buyer of a pre-owned Porsche thousands of dollars. Perhaps even more importantly, it can help avoid the grief of having a dream car turn into a nightmare due to hidden damage or excessive deferred maintenance. But the professionally-performed inspection is actually just the final step in a buying process that is largely under the control of the prospective buyer, and one in which, to be successful, he must be fully engaged.
Deferred maintenance is a polite way of saying that the previous owner didn't take care of his car. But make no mistake: a Porsche is more like a Rolex than a Timex in that it has the potential to last 100 years if properly maintained but will become a piece of very expensive junk if neglected or abused. The Timex, on the other hand, will probably only last three years and not be nearly so personally rewarding as the Rolex. And, instead of maintaining it, you just throw it away when it breaks.
Although the vast majority of Porsche owners recognize this and give their cars excellent care and feeding, there is always a few who will drive the car for a few years, do absolutely nothing to it in the way of either maintenance or repairs and, when confronted with a four or even five figure repair estimate, would rather sell the car to some unsuspecting buyer than face the music of their failure to understand the car and its requirements of ownership. The challenge is to avoid being the individual who gets stuck with such a bill, or at least to avoid paying the price for a well-maintained car while receiving one which actually needs a lot of costly work. This is where the pre-purchase inspection comes in, which is probably the least expensive form of insurance you can buy to help make that pre-owned Porsche turn out to be an enjoyable experience.
Experienced buyers of used cars rarely purchase a car without educating themselves regarding the choice of models and their respective advantages and disadvantages, their strengths and their weaknesses. The 2.7 911's built from 1974 to 1977, which at one time had a bad reputation for engine reliability problems, are now seen to be cars that were really not all that bad, particularly when priced realistically. Many prospective Porsche owners are now giving them a second look. In this case, it would be wise to familiarize oneself with the individual model year differences and with the specific problem areas. In case of the engine, if it has been replaced with a 3.0 or 3.2 liter engine, then it will not be an issue, nor if it has been recently overhauled by a repair facility known for quality and that specializes in the proper "fixes" for this series of engine.
The experienced buyer will establish a database of his own out of the cars that he personally inspects. It is not at all unusual for a buyer to look at 12-15 cars in a twelve-month period prior to making the final decision as to which car to purchase. Of this number, only two or three may be taken to a professional for a pre-purchase inspection. In order to eliminate the remainder, it is helpful for the prospective buyer to become as informed as possible regarding the model he intends to purchase. This can be accomplished in a number of ways. Contacting the local region of the Porsche Club of America is one way. Requesting back issues of PML that feature the model under consideration is another. Obtaining Paul Frere's book, The 911 Story or Pete Zimmerman's The Used 911 Story would also be helpful.
In order to establish a baseline for comparison, it is also vital to be able to spend some time driving a known good example of the desired model. This is where networking with the local PCA region can prove valuable; it is not unusual to find at least one member who has that particular model and who will consent to letting someone else drive it, providing that they can demonstrate a certain level of driving care. This individual may also be able to provide a wealth of information regarding the car, so don't hesitate to make notes as you discuss their car with them.
When it comes time to start looking at cars, it is not at all unusual to want to try to learn as much as possible about the car over the phone, especially if the car is some distance away. Although there is no substitute for personally inspecting the car, a conversation with the seller may well reveal sufficient information about the car and/or the seller to eliminate a particular car from consideration. Although you are buying the car and not the seller, the manner in which the seller answers your questions can be revealing of their attitudes toward the car and indicative of the care it has received. For example, if they don't recall when the last service was, this may indicate that the car has been under-maintained. A seller who can cite when the car was serviced but who admits to certain specific problems with the car may well be considered to be more honest than one who says that everything is perfect.
Once the decision to view the car is made, it is important to take the time to visually inspect the car and make notes on it before driving it. Some buyers even develop their own form (see fig. 1) which lists the important areas to be inspected, such as paint and body condition, interior, wheels, tires, engine leakage and appearance.
If the cosmetic items are up to the buyer's standard, the decision can be made to proceed with a road test. The road test should start with the prospective buyer riding as a passenger with the seller. This will give the buyer the opportunity to form impressions of the car without having to be concerned with driving and also a chance to observe how the seller handles the car. For example, does he leave the car in gear and hold the clutch down at a stoplight, or does he take the car out of gear and let the clutch out, a procedure that can help to greatly extend the life of the clutch.
When the buyer changes places with the seller in order to drive the car, the engine should be shut down. With the key on but prior to starting the engine, the buyer should note if all of the warning lights are operating. When starting the engine, he should watch in the rear view mirror for any smoking and note both the color and the length of time that the engine smokes, as certain models of Porsche do smoke normally on start-up. The engine should idle smoothly.
Prior to engaging first gear and moving away, at least two items should be checked: 1) the presence of a hard and high brake pedal should be confirmed and the clutch adjustment should be checked. With the transmission in neutral, the clutch pedal should be held down for a five-count and then reverse gear should be engaged. Since reverse is not synchronized, any grinding at this point would be cause for concern that the clutch may be dragging, a condition which may not be noticeable in the synchronized forward gears but which can contribute to transmission wear.
When actually driving the car, it is recommended to first drive the car normally at a reasonable speed before attempting any full-throttle runs. This allows the driver to obtain as much feedback from the car as possible, since in maximum effort driving, the driver is not as relaxed. With first gear selected, clutch engagement should be smooth and the car should accelerate without any roughness or hesitation. Gear changes should be smooth and there should be no grinding or abnormal noises from the transmission and no slippage or chattering from the clutch, which can indicate a worn clutch assembly. When making a full-throttle acceleration run, it is advisable to look in the rear view mirror occasionally in order to check for smoking on acceleration and deceleration.
With both hands lifted just slightly from the wheel, the car should track straight ahead on a roadway that is not crowned; the steering wheel spokes should be centered. There should be no friction in the steering wheel and it should be possible to lightly turn the wheel and have it snap back. Excessive friction can indicate a worn steering rack.
Braking should result in the car stopping straight ahead. There should be no abnormal noises under braking and none of the brake system warning lights should illuminate. If the car is equipped with air conditioning, it should be turned on to verify normal operation. When parking the car, verify proper operation of the handbrake; make any notes regarding your impressions of the car.
Pre-Purchase Checklist:
Year: ______________ Model: __________________________ Engine:
Transmission: ________________________________ Limited Slip: Original engine & transmission: _________________ Kardex: Seller: _______________________________________Phone:
Address: _____________________________________City:
Price: ________________________________________
I. Body: Rust: Body exterior: Underbody: Battery box area:
Body damage: Paint: Color: Condition: Original: Repaint:
Glass: Condition: Lights: Condition of Lenses: Interior: Color: Condition: Seats: Seat belts: Power windows: Power door locks: Sound system: Rear view mirrors: Condition: Operation:
II. Wheels: Type: Size: Condition:
III. Tires: Make: Size: Condition:
IV. Engine: Oil leaks: Appearance:
V. Road Test: Warning lights: Brake Pedal: Clutch adjustment: Idle: Acceleration: Smoking: Transmission: Clutch operation: Wheel alignment & steering: Steering wheel centering & free play: Service brake operation: Abnormal noises: Air conditioning operation: Handbrake operation:
VI. Comments:
The Pre-Purchase Inspection, Part II
The Professional Road Test
A pre-purchase inspection of a particular automobile is most valuable when performed by a technician with a solid basis of experience in that model. This is especially true with Porsche automobiles, as most general repair facilities will not have seen enough of these vehicles to have built up the necessary base of experience. Too, and as a generalization with some notable exceptions, most Porsche dealer service departments do not have technicians who are familiar with cars that are more than ten, or at the most, fifteen years old due to turnover of technicians, the fact that the Porsche organization provides technical training for current, and not past, models, and the perception on the part of some dealer principals that this market is simply not worth the trouble. For Porsche models more than ten years old, an independent Porsche specialty shop is usually the best bet for the inspection, although here, too, the prospective buyer must exercise caution. Conversely, for Porsches newer than ten years old a franchised dealer may well be the best choice, since an independent shop may not have either the experience or the equipment required to service these cars.
The prospective buyer should speak with both franchised and independent repair facilities prior to making the decision as to where to have a pre-purchase inspection performed. This can be easily accomplished by telephone providing that the facility has someone who is familiar with both the model of car and the inspection requirements who is available to speak on the phone, something that is not always convenient or permitted at a dealership.
In that first conversation, the prospective buyer should explain what he needs performed and on what year and model of car. Both the cost and scope of the inspection should be described by the representative of the facility. The buyer may ask to see a copy of the inspection checklist that is used by the facility. Any additional information, especially tips that are volunteered, should be considered by the prospective buyer in making his decision, although it is wise to consider these tips and possibly even to verify them by reference to other recognized sources, such as PML or the buyer's own personal database. Sometimes a representative of a repair facility may be aware of a customer who has the correct model available for sale. If the sale is to be handled through the facility, however, the buyer would want to consider having a different facility perform the inspection, unless the car is certified or has a proper warranty.
Once the decision regarding a facility has been made, an appointment for the inspection should be obtained and the car taken to the facility. The car should have at least one-fourth of a tank of fuel to permit sufficient road testing. In order to properly accomplish the inspection, the car should be available for a minimum of four hours to allow time for the inspection itself, the paperwork, to fit the car into the facility's workflow, and to discuss any discrepancies found during the inspection.
It is preferable for the seller to not be present during the inspection and especially during the discussion of discrepancies, as this may lead to a negative reaction on their part, with the seller and the representative of the facility possibly trading insults. Although the buyer is free to share the results of the inspection with the seller, repair facilities feel that their relationship is with the prospective buyer, and would prefer to not be put in the middle of buyer and seller. Because of this possibility, some repair facilities do not perform pre-purchase inspections as a matter of policy.
Once the repair order is completed, the car will be assigned to a technician, who should be journeyman level with special training and experience for the specific model at hand. This technician should use an inspection checklist with all of the major and minor items on it that will be checked during the inspection, a checklist that has been developed by him, the repair facility, or the manufacturer itself. The checklist may be the same one developed for use on a major maintenance service, such as the 30,000-mile service, with additional checks for accident and cosmetic damage as well as for corrosion.
The inspection will begin with the technician mentally reviewing the problem areas for this type of car. A road test of the vehicle performed by the technician will be the next step, although as he approaches the vehicle, the technician will "walk around" the vehicle and note any external items that would be cause for concern. As he sits in the vehicle, the tech will notice the condition of the interior: is it clean, well kept, and free from excessive wear and tear. Although it is difficult to generalize, a car that shows obvious signs of cosmetic care may also have been well cared for mechanically. Some buyers have even been known to turn the radio on to see to what stations the presets are on, with the theory being that classical musical listeners are easier on their car than are those who choose heavy metal. Others prefer cars that have not been smoked in for similar reasons. It is doubtful if the technician would go so far as to check the radio and the ashtray, and one hopes he would look for more tangible indicators of the car's condition.
As with the buyer, the tech will check that all of the warning lights are operating. Some cars with low oil pressure have been found with the oil pressure warning light disconnected because it was flickering when the engine idled. Although all 911's have very low oil pressure at idle, the warning light should still work with the engine off, as should the alternator warning light. On some Porsche models, the alternator warning light not working can signal an electrical fault in the alternator.
Satisfied that the lights are working, the tech will next press on the brake pedal to insure hydraulic pressure in the brake system. On cars equipped with power brakes, he will maintain that pressure while starting the engine. If the pedal gradually moves down or becomes "softer" as the engine starts, this will verify operation of the brake power booster.
Once the engine is started, the tech will spend a minute or two listening to the engine, checking the engine gauges, and allowing the engine oil to circulate. He will also check clutch operation and adjustment. In all manual transmission-equipped Porsches and 911's built prior to 1987, the clutch should be held in for five seconds and then reverse gear selected. Any grinding then would be cause for concern that there is a clutch or transmission problem. The forward gears cannot be used for this test since they are synchronized and will not grind, although they will be more difficult to engage if the clutch is dragging, as would be the case were it out of adjustment or in need of replacement. 911's built from the 1987 model year are equipped with the G-50 transaxle, which employs a synchronized reverse gear, so the grinding test is not possible, although it is recommended to check for higher than normal shifting effort, something which could best be done by someone who had driven a number of these cars.
The clutch should be engaged and the car reversed at least one hundred feet in order to check for abnormal noises in reverse gear. Then the car should be driven away normally or, if anything, at a slower than normal speed. The tech should be experienced enough as a driver (competition experience is helpful) to be able to completely relax in the car so that his senses are all HEIGHTened and thus more alert to abnormal sounds and other sensory inputs.
An owner of a 1987 911 learned the value of this kind of experience recently when he took his car in for an oil change to a repair facility operated by a technician with a racing background. Twice in the previous few months the owner had felt a slight roughness in the accelerator pedal when lifting off the throttle, but because it had been so intermittent he didn't mention it to the technician. The tech, however, noted it during his routine test drive and decided to pursue the problem. When the owner picked the car up the technician informed him that a broken cruise control fitting had been threatening to jam the throttle wide open, and that the technician had been able to repair it. A less experienced, less sensitive tech would probably have not even felt the problem, which was one with the potential to cause a considerable amount of damage.
Proceeding with the road test, the tech will check the operation of all of the forward gears while noting the clutch action, being especially alert for chattering (vibration, usually most noticeable when starting from rest) or slipping. A conventionally used test for clutch slippage, accelerating in first and then shifting directly into the highest gear to see if the clutch slips, is not recommended, especially for 911 models. Porsche clutches are sized to be the best compromise between weight and clamping pressure for road- and not drag-racing, and generally will not tolerate this kind of abuse.
Although second gear will usually be the first to show signs of synchronizer failure (grinding), it is also necessary to select first gear while rolling at five mph to ensure that this gear's synchronizer or sliding sleeve has not been damaged, either of which will be costly to repair. All of the gears should be quiet in operation as should be the differential gears, which, if worn, may produce noise beginning at 30 mph and increasing with tire rpm. If the clutch release bearing has failed, it will produce noise with the clutch pushed all the way down. A clunking noise that occurs whenever the clutch is let out in a 924/944/968 series car would be considered normal unless it is accompanied by excessive driveline play when accelerating or decelerating, which may be a sign of a failed rubber clutch disc or a worn transaxle.
Steering should be checked for ease of effort, centering of the wheel, and for any tendency to pull to one side or the other. To check for this last item, the wheel should be lightly held between the fingers or the car even allowed to run without any hand contact on the wheel. It should also be noted if there is any steering wheel shake, vibration, or shimmy. Braking should occur without any pulling or any abnormal noise or vibration, which may indicate a warped brake rotor. The brake pedal should remain firm when pressure is applied, indicating a good brake master cylinder and no hydraulic leaks.
During this time, the tech will be aware of not only the transmission, clutch and brake operation, but of the engine sound and performance as well. Are all of the sounds coming from the engine normal? Is there any roughness, hesitation or indication that the engine is not performing properly? Is there any sign of smoke in the rear view mirrors? The tech will have noted in his walk-around if there was any sign of blown oil on the rear of the car, which can emanate from either engine oil leaks or from the exhaust of an engine with worn rings or valve guides.
Assuming that all of these tests have not revealed any major mechanical problems, the tech will proceed with a full throttle acceleration run, at least through the first two or three gears, depending upon the car's performance potential. Depending upon the age and condition of the car, the engine will be taken very close to the redline. Experienced Porsche techs will use caution, however, particularly with a type 356 or 912, where it is known that crankshafts can and have broken. An early 911 can also be more vulnerable to high rpm damage than, say, a 1978 or newer car, so some techs advocate a cushion of ten per cent (or more) below the redline. It simply is not necessary to test the rev limiter, and, on some models, it may well have been removed.
As a final test, the tech will operate the heating and ventilating system through its range, particularly if the car is equipped with air conditioning. He will also check the sunroof, power window and power mirror and lock operation, as well as the operation of the power seats.
Notes regarding any problem areas will be made and the car will be returned to the repair facility for the rest of the inspection. The return trip will be made as was the outbound one: at reduced speed so as to more effectively note any problems which may have cropped up during the road test or because the car is now fully at operating temp. These problems may include engine, transmission, or clutch performance, smoking, or abnormal noises.
Part III - The Professional Mechanical Inspection
After completion of the road test portion of his inspection, the technician will want to continue with the in-depth, mechanical portion. Prior to switching the engine off the tech will check for correct operation of the heating and ventilating controls, including checking that the air conditioning outlet temperatures are correct for the current ambient temperature. A 30-degree drop from ambient is considered normal. Although warning lights will have already been checked, the tech will now verify correct operation of the exterior lights, wipers, and horn. Prior to operating the wipers, he will spray windshield solvent on the windshield (from a bottle and not the car's own washer system) so as not to damage a dry glass. The handbrake should be checked for correct extension when applied. More than five to seven clicks, depending upon the model, may indicate the need for adjustment or replacement of the emergency brake linings.
Operation and condition of the windows whether power or manual, the rear view mirrors, and the door handles and locks will all be checked, as will be the seats, seat belts, sun visors, and sun visor retaining clips. Door hinges and door check mechanisms will be inspected, and the hood and trunk release mechanisms will be exercised and their correct operation verified. The spare tire should be removed and both the front and rear internal structure of the car inspected for the presence of repaired accident damage. The condition of the spare as well as the presence of a tire air compressor and factory tool kit should also be noted. The battery area should be inspected for corrosion, particularly 914's and all 356, 911 and 912 models, especially those where a vented battery has been installed without the vent hose being installed and/or connected. The level and state of charge of battery electrolyte should be checked, as should the output of the alternator under load.
While in the trunk compartment of models so equipped (356, 911, 912, 914), brake fluid level and condition should be checked, as should any signs of leakage, particularly on the brake booster. Dirty brake fluid may be taken as a sign that the vehicle has been under-maintained, and test kits are available to chemically determine if there is moisture present in the brake fluid which can cause internal damage to brake hydraulic components.
Although the road test will have given the tech an idea of the condition of the suspension components, a so-called bounce test of the shock absorbers will be performed prior to placing the vehicle on a hoist. The bumper or a fender (not recommended on the aluminum-fendered 928 series) is depressed with the hands and the vehicle is allowed to return to its normal HEIGHT, with the oscillation being dampened out in no more than one or one-and-one half cycles, and the freedom of movement of the suspension not being interfered with by a "frozen" shock. On many Porsche models, the bounce test may not be conclusive, except to reveal a frozen shock, so the road test and later visual inspection for signs of leakage become more critical in locating a bad shock. In some cases, it is not unusual for original equipment Porsche shocks to last 100,000 miles, so mileage since the shock was last changed is a consideration as well.
When the car is placed on a hoist, wheel bearing play at all four wheels should be checked. The wheels and tires should be inspected for condition and tread depth, which should be noted on the inspection report. Tire wear patterns should be checked for signs of imbalance, alignment, or suspension problems. All four wheels should then be removed. The percentage of brake lining remaining should be noted, as should the condition and thickness of the brake rotors. Uneven pad wear on the same axle may indicate a frozen, inoperative, or incorrectly assembled brake caliper. On models equipped with a brake proportioning valve (914, 928) the valve should be inspected for signs of leakage. Brake hydraulic hoses and metal lines should be inspected for condition along with any vacuum hoses connected to the brake booster. "Stainless steel" type brake hoses should be noted for replacement unless the date of installation is known, since it is not possible to visually inspect this type of hose. For this reason, many techs recommend against their use on anything but cars that are driven exclusively on the track and where the lines are replaced on a regular basis.
Any protective undertrays should be removed and steering rack leakage or boot deterioration should be noted, as should ball joint or, -- on the 356, king and link pin, -- wear. Broken ball joint or tie-rod end dust boots should be noted, as should any signs of wear or looseness in the suspension or steering linkage. Stabilizer bar bushings and mounts should be inspected., particularly the rear stabilizer bar mounts on the 911 series, which are prone to cracking.
The floor pan itself should be carefully inspected for signs of corrosion, accident damage, or repairs. Many buyers, for example, would prefer not to acquire a car and then discover that it had been "sectioned", or made out of two or even three other cars whose pans have been welded together. While pan replacement is not unusual, particularly on the older models that were built prior to the introduction of corrosion-resistant steel in 1975, the quality of the repair can be a major factor in determining resale value.
The fuel tank, pump, and hoses should be checked for condition and any signs of leakage. The tank should be inspected for any damage such as might occur if something had been run over. The exhaust system should likewise be checked for any signs of damage, leakage, or corrosion. Heat shields, mufflers, manifolds, heat exchangers, pipes, hoses and all other exhaust system components should be inspected. The absence of any required emission control equipment should be noted, as should the condition of exhaust clamps, brackets, and hangers. Heater valves, hoses, and cables should also be checked.
The transmission fluid level should be checked, as should the transmission itself for any signs of leakage. Failed constant velocity joint boots and shift rod boots should be noted. The underside of the engine should be checked for any signs of fluid leakage and the type of fluid noted. Engine and transmission rubber mounts should be inspected for sagging or cracking. 944 and 924S series engine mounts should be checked for the proper HEIGHT dimension to insure that they have not failed internally. The oil pan and crankcase should be checked for any signs of accident damage.
Engine oil level and appearance should be checked, although with modern detergent oils it is difficult to visually gauge condition since the oil becomes "dirty" very quickly; this only indicates that the oil is doing its job by suspending contaminants rather than allowing them to remain in the lubricating system. The engine compartment should be inspected for any signs of fuel, oil, or coolant leakage, and for any deteriorated or missing rubber parts, including the engine compartment seal which runs around the perimeter of the compartment in air-cooled models. If this seal has been omitted, engine overheating and damage can occur. If the car is liquid-cooled, coolant level and condition should be checked. Using a hydrometer for the purpose, it is possible to tell to what temperature the coolant will offer freezing protection. A high number or the presence of contamination may indicate that the coolant is in need of changing. Severe contamination, commonly referred to as sludge or mud, in a 944 may indicate a failed oil-water intercooler seal.
The oil reservoir in air-cooled 911 models should be inspected for condition and signs of leakage, particularly around the oil level sending unit and on all of the oil lines leading to the reservoir. On models without self-adjusting valves, the valve covers may be inspected for any indication that they have been removed in the recent past, and for signs of leakage. If the valve covers do not appear to have been off in quite some time, this, too, may be taken as a sign that the car's maintenance has been neglected. Both air- and liquid-cooled models of Porsches have numerous places from which oil can leak, so in the case of an engine which is covered with oil it is wise to clean the engine and run it for a period of time prior to verifying the location of any leaks.
The wheels should now be reinstalled in their original positions and properly torqued, the undertrays reinstalled, and the car lowered to the ground. The engine air filter element should be removed and inspected, as this will provide an indication of when the car was last serviced. One spark plug or a distributor cap may be removed for another indication. Of course, if the client has requested a compression test, all of the spark plugs will be removed.
The necessity for a compression test during a pre-purchase inspection is a subject on which experts may rightfully disagree. Because additional expense over that for the inspection is involved, some buyers like to reserve it only for cars which have passed their other tests, or if there is a question generated by sluggish performance, a rough idle, or uneven cranking when the engine is being motored by the starter. When a weak cylinder comes up, the starter will noticeably speed up, except in the case of a 944 that has sheared a timing belt, where the starter turns faster on every cylinder. Even in that case, the difference in sound is noticeable to an experienced tech, although here the problem is more obvious since the engine also won't run. A less expensive alternative to the dynamic compression test, where a gauge is used to actually measure the compression in each cylinder, is a relative compression test which uses an engine analyzer to electronically establish relative compression values for the cylinders or which shorts out one cylinder at a time in what is known as a cylinder balance test and measures the rpm lost for each cylinder. What these tests will not reveal, however, is an engine in which all of the cylinders are worn equally and which have low compression across the board.
On models equipped with a toothed rubber timing belt, a visual inspection of both the belt and the oil seals behind it is recommended. If the belt has been recently replaced but the oil seals have not, the life of the belt will be drastically shortened, possibly even leading to belt failure significantly before the normally expected service interval. Any cracking or deterioration anywhere on the belt is cause for replacement, as would be a belt that has not been operating under the proper tension. While checking belts, the engine accessory drive belts should also be inspected, as should the water and power steering pumps for any signs of leakage. In some models, it is not possible to see the water pump without significant disassembly, so, as with the compression test, the cost will have to be weighed along with other factors.
Overall engine compartment cleanliness should be noted, with the theory being that a clean engine may be taken as a sign that the previous owner and his repair facility have taken some pride in the car. Unfortunately, this can also be a sign of an unscrupulous individual or business, especially if the engine has been sprayed with clear lacquer to give it a "like new" appearance, although even here appearances can be deceiving and the entire picture must be taken into consideration, including, but not limited to, the results of the inspection we have now completed.
When the inspection has been completed, the buyer should expect to see a written report of any mechanical discrepancies that were noted during the course of the inspection. The repair facility should also be able to provide estimated costs of repair for these items along with additional information on both the vehicle's overall condition and on how it compares to other similar vehicles with which they are familiar. The Porsche specialist can become, especially to the first-time Porsche buyer, the single most important source of information that is available.
Potential buyers need to remind themselves to not be discouraged by an apparently unfavorable inspection report, but to view it as a necessary part of "doing their homework" prior to making what is a major investment. All cars have problems, even brand new ones. In the case of used vehicles, some will definitely have fewer problems than others, and the idea is always to purchase the best vehicle (in overall condition) that your budget will allow, since repair costs, unlike the cost of the vehicle, are always paid in current dollars and are not depreciated. Many buyers use the inspection report as a negotiating tool to successfully effect a reduction in the vehicle's price or, in some cases, to aide in making the decision to reject a particular vehicle as not being suitable for their needs. Buyers who proceed with a purchase of an inspected vehicle do so with a far greater knowledge of what they have and are not subject to nearly so many "surprises" as is the individual who purchases a car at the swap meet on Sunday only to be told by his technician on Monday that the cost of the needed repairs exceeds the cost of the vehicle, not to mention what it will be worth after it is repaired.
On the other hand, if the needed repairs are known, in most cases they can be easily prioritized so that the costs can be spread out over a year or more, during which time the vehicle can still be driven and enjoyed while it is returned to optimum condition. This way, instead of taking away from the excitement of obtaining a new toy, the inspection report can be seen more as an agenda for returning one example of driving in its finest form to, well, its finest form. And, as is the case with the older Porsche models, many repairs can even be performed by the owner, thus resulting in additional savings.
1. Check for Dual Mass Flywheel Transmission noises (rattling, knocking noises at engine start, load shift, during idling or when switching off the engine). If I hear this I need to hand it over to the service folks since test needs to be performed by service department to determine if replacement is needed or if working correctly and noise is related to a different component.
2. Check Oil Pressure. If oil pressure light is on, lack of oil pressure when the engine is first started. Non-return check valve is installed between the oil tank and the engine to prevent tank from emptying into the crankcase when engine is turned off. Modified check valve installed from engine number M96/70-64 1 01282. New part has a light blue paint dot.
3. Check to see if clutch pedal sticks. Clutch pedal may not return to its initial position or may become stuck. The axial motion in the plug-in couplings and the associated rolling of the sealing ring can admit air into the hydraulic system. A snap ring, PN 999 230 685 40, must be fitted and the system.
4. Check if the clutch pedal does not fully reach original position. After pressing the clutch, the clutch pedal is slow to come back up and does not fully reach its original position. This is caused by air in the hydraulic system.
5. Check for noises in the steering. Clicking or grating noises during steering. Grating- This noise occurs when steering movements are made around the center position to full lock position. New stop plate required PN 996 343 107 03. Clicking - This noise occurs shortly before turning the steering wheel to full lock. A loose rod nut causes the noise. The solution is to tighten the strut piston rod fastening nut to the specified torque. Also, a longer piece of hose needs to be installed in the first few turns of the spring to replace shorter one initially in place.
6. Check for loud whistling noise from the engine area . A loud whistling noise can be heard (both inside and outside) from the engine area while driving. The noise is caused by the pressure control valve in the steering oil reservoir. Valve vibrates strongly when hydraulic oil flows through it. Fix is to replace the complete steering oil reservoir with the modified pressure control valve - PN 996 314 920 34
7. Check for noises in the rear seat well. Audible clicking-type noises in the rear seat well due to movements of the transverse reinforcement tube and contact with the rear seat well panel. Fix is to install felt tape between the reinforcement tube and the rear seat well panel.
11. Check the microswitch. Front lid lock issues with micro switch. Micro switch located on the bottom part of the front lid latch may stick causing: the light not to illuminate when the trunk is opened; the light not to go off when the trunk is closed (draining the battery); the alarm horn will sound when locking the car. A new micro switch was installed from the middle of Feb 2000 and can be identified by a yellow or blue paint dot in the micro switch.
8. Check for noises in the door lock area. Catch bar rubbing in the door lock. Fix is to spray silicone lubricant spray in the affected areas (in the inner area of the lock).
9. Check for noises from sunroof frame Movement between the new sunroof frame and the roof causes creaking noises. Fix is to install two strips of Teflon tape and retorque bolts to new specs of 9.7Nm(7.4ft-lb).
10. Check for noises in the Tilting/Sliding sunroof. Muffled rattle from rear area of the tilting/sliding sunroof due to the loss of edge guard for the water drain bracket. When the edge guard is missing, the roof liner can bump into the sliding sunroof frame and cause noises. Fix is to install new edge guard for the water drain bracket.
11. Check rear spoiler operation
12. Check vanity mirror. If it is not working the fix (after validating fuse and light bulb) is to replace the vanity mirror PN 996 731 903 01 01C
13. Check if airbag warning light comes on. If so and it gives: Fault Codes 46 and 49. Fix is to change the seat plug connector and install a new belt buckle (passenger and driver side)
14. Validate that the memory for the seat and mirror work correctly when using the keys. As of model year 2001 if a locked vehicle is opened with the key head remote control, the driver's seat and the door mirror will be set in the position stored in the seat memory. Due to hardware fault, the radio code and the transponder code have been entered in different storage positions in the alarm control unit. Fix is to reprogram all the keys. Spare key is required when doing this.
15. Validate remote control range. If range sucks even after replacing battery the fix is to re-route antenna lead.
16. Check that the VIN matches number on the title and/or other documentation
17. Closely visual inspect the paint. Look closely at every panel. Spend at least 30 seconds per panel. Stand back and look at an entire side of the car. Make sure that the color does not vary (sign of repaint). Check that one wheel is not in better shap than any other (wheel replacement due to accident).
18. Check the tires for wear. Check if all tires are the same brand and type.
19. Check the undercarriage. Look for any scrapes/damage. Ideally put it up on a lift. Look for anything loose or worn. Make sure that the components/wear seems reasonable for the mileage on the car.
20. Check the brake pads and rotors for wear and correct thickness.
21. Check for wheel bearing play.
PRE PURCHASE INSPECTION:
A pre-purchase inspection performed properly by a technician with both product knowledge and a broad experience base can save a prospective buyer of a pre-owned Porsche thousands of dollars. Perhaps even more importantly, it can help avoid the grief of having a dream car turn into a nightmare due to hidden damage or excessive deferred maintenance. But the professionally-performed inspection is actually just the final step in a buying process that is largely under the control of the prospective buyer, and one in which, to be successful, he must be fully engaged.
Deferred maintenance is a polite way of saying that the previous owner didn't take care of his car. But make no mistake: a Porsche is more like a Rolex than a Timex in that it has the potential to last 100 years if properly maintained but will become a piece of very expensive junk if neglected or abused. The Timex, on the other hand, will probably only last three years and not be nearly so personally rewarding as the Rolex. And, instead of maintaining it, you just throw it away when it breaks.
Although the vast majority of Porsche owners recognize this and give their cars excellent care and feeding, there is always a few who will drive the car for a few years, do absolutely nothing to it in the way of either maintenance or repairs and, when confronted with a four or even five figure repair estimate, would rather sell the car to some unsuspecting buyer than face the music of their failure to understand the car and its requirements of ownership. The challenge is to avoid being the individual who gets stuck with such a bill, or at least to avoid paying the price for a well-maintained car while receiving one which actually needs a lot of costly work. This is where the pre-purchase inspection comes in, which is probably the least expensive form of insurance you can buy to help make that pre-owned Porsche turn out to be an enjoyable experience.
Experienced buyers of used cars rarely purchase a car without educating themselves regarding the choice of models and their respective advantages and disadvantages, their strengths and their weaknesses. The 2.7 911's built from 1974 to 1977, which at one time had a bad reputation for engine reliability problems, are now seen to be cars that were really not all that bad, particularly when priced realistically. Many prospective Porsche owners are now giving them a second look. In this case, it would be wise to familiarize oneself with the individual model year differences and with the specific problem areas. In case of the engine, if it has been replaced with a 3.0 or 3.2 liter engine, then it will not be an issue, nor if it has been recently overhauled by a repair facility known for quality and that specializes in the proper "fixes" for this series of engine.
The experienced buyer will establish a database of his own out of the cars that he personally inspects. It is not at all unusual for a buyer to look at 12-15 cars in a twelve-month period prior to making the final decision as to which car to purchase. Of this number, only two or three may be taken to a professional for a pre-purchase inspection. In order to eliminate the remainder, it is helpful for the prospective buyer to become as informed as possible regarding the model he intends to purchase. This can be accomplished in a number of ways. Contacting the local region of the Porsche Club of America is one way. Requesting back issues of PML that feature the model under consideration is another. Obtaining Paul Frere's book, The 911 Story or Pete Zimmerman's The Used 911 Story would also be helpful.
In order to establish a baseline for comparison, it is also vital to be able to spend some time driving a known good example of the desired model. This is where networking with the local PCA region can prove valuable; it is not unusual to find at least one member who has that particular model and who will consent to letting someone else drive it, providing that they can demonstrate a certain level of driving care. This individual may also be able to provide a wealth of information regarding the car, so don't hesitate to make notes as you discuss their car with them.
When it comes time to start looking at cars, it is not at all unusual to want to try to learn as much as possible about the car over the phone, especially if the car is some distance away. Although there is no substitute for personally inspecting the car, a conversation with the seller may well reveal sufficient information about the car and/or the seller to eliminate a particular car from consideration. Although you are buying the car and not the seller, the manner in which the seller answers your questions can be revealing of their attitudes toward the car and indicative of the care it has received. For example, if they don't recall when the last service was, this may indicate that the car has been under-maintained. A seller who can cite when the car was serviced but who admits to certain specific problems with the car may well be considered to be more honest than one who says that everything is perfect.
Once the decision to view the car is made, it is important to take the time to visually inspect the car and make notes on it before driving it. Some buyers even develop their own form (see fig. 1) which lists the important areas to be inspected, such as paint and body condition, interior, wheels, tires, engine leakage and appearance.
If the cosmetic items are up to the buyer's standard, the decision can be made to proceed with a road test. The road test should start with the prospective buyer riding as a passenger with the seller. This will give the buyer the opportunity to form impressions of the car without having to be concerned with driving and also a chance to observe how the seller handles the car. For example, does he leave the car in gear and hold the clutch down at a stoplight, or does he take the car out of gear and let the clutch out, a procedure that can help to greatly extend the life of the clutch.
When the buyer changes places with the seller in order to drive the car, the engine should be shut down. With the key on but prior to starting the engine, the buyer should note if all of the warning lights are operating. When starting the engine, he should watch in the rear view mirror for any smoking and note both the color and the length of time that the engine smokes, as certain models of Porsche do smoke normally on start-up. The engine should idle smoothly.
Prior to engaging first gear and moving away, at least two items should be checked: 1) the presence of a hard and high brake pedal should be confirmed and the clutch adjustment should be checked. With the transmission in neutral, the clutch pedal should be held down for a five-count and then reverse gear should be engaged. Since reverse is not synchronized, any grinding at this point would be cause for concern that the clutch may be dragging, a condition which may not be noticeable in the synchronized forward gears but which can contribute to transmission wear.
When actually driving the car, it is recommended to first drive the car normally at a reasonable speed before attempting any full-throttle runs. This allows the driver to obtain as much feedback from the car as possible, since in maximum effort driving, the driver is not as relaxed. With first gear selected, clutch engagement should be smooth and the car should accelerate without any roughness or hesitation. Gear changes should be smooth and there should be no grinding or abnormal noises from the transmission and no slippage or chattering from the clutch, which can indicate a worn clutch assembly. When making a full-throttle acceleration run, it is advisable to look in the rear view mirror occasionally in order to check for smoking on acceleration and deceleration.
With both hands lifted just slightly from the wheel, the car should track straight ahead on a roadway that is not crowned; the steering wheel spokes should be centered. There should be no friction in the steering wheel and it should be possible to lightly turn the wheel and have it snap back. Excessive friction can indicate a worn steering rack.
Braking should result in the car stopping straight ahead. There should be no abnormal noises under braking and none of the brake system warning lights should illuminate. If the car is equipped with air conditioning, it should be turned on to verify normal operation. When parking the car, verify proper operation of the handbrake; make any notes regarding your impressions of the car.
Pre-Purchase Checklist:
Year: ______________ Model: __________________________ Engine:
Transmission: ________________________________ Limited Slip: Original engine & transmission: _________________ Kardex: Seller: _______________________________________Phone:
Address: _____________________________________City:
Price: ________________________________________
I. Body: Rust: Body exterior: Underbody: Battery box area:
Body damage: Paint: Color: Condition: Original: Repaint:
Glass: Condition: Lights: Condition of Lenses: Interior: Color: Condition: Seats: Seat belts: Power windows: Power door locks: Sound system: Rear view mirrors: Condition: Operation:
II. Wheels: Type: Size: Condition:
III. Tires: Make: Size: Condition:
IV. Engine: Oil leaks: Appearance:
V. Road Test: Warning lights: Brake Pedal: Clutch adjustment: Idle: Acceleration: Smoking: Transmission: Clutch operation: Wheel alignment & steering: Steering wheel centering & free play: Service brake operation: Abnormal noises: Air conditioning operation: Handbrake operation:
VI. Comments:
The Pre-Purchase Inspection, Part II
The Professional Road Test
A pre-purchase inspection of a particular automobile is most valuable when performed by a technician with a solid basis of experience in that model. This is especially true with Porsche automobiles, as most general repair facilities will not have seen enough of these vehicles to have built up the necessary base of experience. Too, and as a generalization with some notable exceptions, most Porsche dealer service departments do not have technicians who are familiar with cars that are more than ten, or at the most, fifteen years old due to turnover of technicians, the fact that the Porsche organization provides technical training for current, and not past, models, and the perception on the part of some dealer principals that this market is simply not worth the trouble. For Porsche models more than ten years old, an independent Porsche specialty shop is usually the best bet for the inspection, although here, too, the prospective buyer must exercise caution. Conversely, for Porsches newer than ten years old a franchised dealer may well be the best choice, since an independent shop may not have either the experience or the equipment required to service these cars.
The prospective buyer should speak with both franchised and independent repair facilities prior to making the decision as to where to have a pre-purchase inspection performed. This can be easily accomplished by telephone providing that the facility has someone who is familiar with both the model of car and the inspection requirements who is available to speak on the phone, something that is not always convenient or permitted at a dealership.
In that first conversation, the prospective buyer should explain what he needs performed and on what year and model of car. Both the cost and scope of the inspection should be described by the representative of the facility. The buyer may ask to see a copy of the inspection checklist that is used by the facility. Any additional information, especially tips that are volunteered, should be considered by the prospective buyer in making his decision, although it is wise to consider these tips and possibly even to verify them by reference to other recognized sources, such as PML or the buyer's own personal database. Sometimes a representative of a repair facility may be aware of a customer who has the correct model available for sale. If the sale is to be handled through the facility, however, the buyer would want to consider having a different facility perform the inspection, unless the car is certified or has a proper warranty.
Once the decision regarding a facility has been made, an appointment for the inspection should be obtained and the car taken to the facility. The car should have at least one-fourth of a tank of fuel to permit sufficient road testing. In order to properly accomplish the inspection, the car should be available for a minimum of four hours to allow time for the inspection itself, the paperwork, to fit the car into the facility's workflow, and to discuss any discrepancies found during the inspection.
It is preferable for the seller to not be present during the inspection and especially during the discussion of discrepancies, as this may lead to a negative reaction on their part, with the seller and the representative of the facility possibly trading insults. Although the buyer is free to share the results of the inspection with the seller, repair facilities feel that their relationship is with the prospective buyer, and would prefer to not be put in the middle of buyer and seller. Because of this possibility, some repair facilities do not perform pre-purchase inspections as a matter of policy.
Once the repair order is completed, the car will be assigned to a technician, who should be journeyman level with special training and experience for the specific model at hand. This technician should use an inspection checklist with all of the major and minor items on it that will be checked during the inspection, a checklist that has been developed by him, the repair facility, or the manufacturer itself. The checklist may be the same one developed for use on a major maintenance service, such as the 30,000-mile service, with additional checks for accident and cosmetic damage as well as for corrosion.
The inspection will begin with the technician mentally reviewing the problem areas for this type of car. A road test of the vehicle performed by the technician will be the next step, although as he approaches the vehicle, the technician will "walk around" the vehicle and note any external items that would be cause for concern. As he sits in the vehicle, the tech will notice the condition of the interior: is it clean, well kept, and free from excessive wear and tear. Although it is difficult to generalize, a car that shows obvious signs of cosmetic care may also have been well cared for mechanically. Some buyers have even been known to turn the radio on to see to what stations the presets are on, with the theory being that classical musical listeners are easier on their car than are those who choose heavy metal. Others prefer cars that have not been smoked in for similar reasons. It is doubtful if the technician would go so far as to check the radio and the ashtray, and one hopes he would look for more tangible indicators of the car's condition.
As with the buyer, the tech will check that all of the warning lights are operating. Some cars with low oil pressure have been found with the oil pressure warning light disconnected because it was flickering when the engine idled. Although all 911's have very low oil pressure at idle, the warning light should still work with the engine off, as should the alternator warning light. On some Porsche models, the alternator warning light not working can signal an electrical fault in the alternator.
Satisfied that the lights are working, the tech will next press on the brake pedal to insure hydraulic pressure in the brake system. On cars equipped with power brakes, he will maintain that pressure while starting the engine. If the pedal gradually moves down or becomes "softer" as the engine starts, this will verify operation of the brake power booster.
Once the engine is started, the tech will spend a minute or two listening to the engine, checking the engine gauges, and allowing the engine oil to circulate. He will also check clutch operation and adjustment. In all manual transmission-equipped Porsches and 911's built prior to 1987, the clutch should be held in for five seconds and then reverse gear selected. Any grinding then would be cause for concern that there is a clutch or transmission problem. The forward gears cannot be used for this test since they are synchronized and will not grind, although they will be more difficult to engage if the clutch is dragging, as would be the case were it out of adjustment or in need of replacement. 911's built from the 1987 model year are equipped with the G-50 transaxle, which employs a synchronized reverse gear, so the grinding test is not possible, although it is recommended to check for higher than normal shifting effort, something which could best be done by someone who had driven a number of these cars.
The clutch should be engaged and the car reversed at least one hundred feet in order to check for abnormal noises in reverse gear. Then the car should be driven away normally or, if anything, at a slower than normal speed. The tech should be experienced enough as a driver (competition experience is helpful) to be able to completely relax in the car so that his senses are all HEIGHTened and thus more alert to abnormal sounds and other sensory inputs.
An owner of a 1987 911 learned the value of this kind of experience recently when he took his car in for an oil change to a repair facility operated by a technician with a racing background. Twice in the previous few months the owner had felt a slight roughness in the accelerator pedal when lifting off the throttle, but because it had been so intermittent he didn't mention it to the technician. The tech, however, noted it during his routine test drive and decided to pursue the problem. When the owner picked the car up the technician informed him that a broken cruise control fitting had been threatening to jam the throttle wide open, and that the technician had been able to repair it. A less experienced, less sensitive tech would probably have not even felt the problem, which was one with the potential to cause a considerable amount of damage.
Proceeding with the road test, the tech will check the operation of all of the forward gears while noting the clutch action, being especially alert for chattering (vibration, usually most noticeable when starting from rest) or slipping. A conventionally used test for clutch slippage, accelerating in first and then shifting directly into the highest gear to see if the clutch slips, is not recommended, especially for 911 models. Porsche clutches are sized to be the best compromise between weight and clamping pressure for road- and not drag-racing, and generally will not tolerate this kind of abuse.
Although second gear will usually be the first to show signs of synchronizer failure (grinding), it is also necessary to select first gear while rolling at five mph to ensure that this gear's synchronizer or sliding sleeve has not been damaged, either of which will be costly to repair. All of the gears should be quiet in operation as should be the differential gears, which, if worn, may produce noise beginning at 30 mph and increasing with tire rpm. If the clutch release bearing has failed, it will produce noise with the clutch pushed all the way down. A clunking noise that occurs whenever the clutch is let out in a 924/944/968 series car would be considered normal unless it is accompanied by excessive driveline play when accelerating or decelerating, which may be a sign of a failed rubber clutch disc or a worn transaxle.
Steering should be checked for ease of effort, centering of the wheel, and for any tendency to pull to one side or the other. To check for this last item, the wheel should be lightly held between the fingers or the car even allowed to run without any hand contact on the wheel. It should also be noted if there is any steering wheel shake, vibration, or shimmy. Braking should occur without any pulling or any abnormal noise or vibration, which may indicate a warped brake rotor. The brake pedal should remain firm when pressure is applied, indicating a good brake master cylinder and no hydraulic leaks.
During this time, the tech will be aware of not only the transmission, clutch and brake operation, but of the engine sound and performance as well. Are all of the sounds coming from the engine normal? Is there any roughness, hesitation or indication that the engine is not performing properly? Is there any sign of smoke in the rear view mirrors? The tech will have noted in his walk-around if there was any sign of blown oil on the rear of the car, which can emanate from either engine oil leaks or from the exhaust of an engine with worn rings or valve guides.
Assuming that all of these tests have not revealed any major mechanical problems, the tech will proceed with a full throttle acceleration run, at least through the first two or three gears, depending upon the car's performance potential. Depending upon the age and condition of the car, the engine will be taken very close to the redline. Experienced Porsche techs will use caution, however, particularly with a type 356 or 912, where it is known that crankshafts can and have broken. An early 911 can also be more vulnerable to high rpm damage than, say, a 1978 or newer car, so some techs advocate a cushion of ten per cent (or more) below the redline. It simply is not necessary to test the rev limiter, and, on some models, it may well have been removed.
As a final test, the tech will operate the heating and ventilating system through its range, particularly if the car is equipped with air conditioning. He will also check the sunroof, power window and power mirror and lock operation, as well as the operation of the power seats.
Notes regarding any problem areas will be made and the car will be returned to the repair facility for the rest of the inspection. The return trip will be made as was the outbound one: at reduced speed so as to more effectively note any problems which may have cropped up during the road test or because the car is now fully at operating temp. These problems may include engine, transmission, or clutch performance, smoking, or abnormal noises.
Part III - The Professional Mechanical Inspection
After completion of the road test portion of his inspection, the technician will want to continue with the in-depth, mechanical portion. Prior to switching the engine off the tech will check for correct operation of the heating and ventilating controls, including checking that the air conditioning outlet temperatures are correct for the current ambient temperature. A 30-degree drop from ambient is considered normal. Although warning lights will have already been checked, the tech will now verify correct operation of the exterior lights, wipers, and horn. Prior to operating the wipers, he will spray windshield solvent on the windshield (from a bottle and not the car's own washer system) so as not to damage a dry glass. The handbrake should be checked for correct extension when applied. More than five to seven clicks, depending upon the model, may indicate the need for adjustment or replacement of the emergency brake linings.
Operation and condition of the windows whether power or manual, the rear view mirrors, and the door handles and locks will all be checked, as will be the seats, seat belts, sun visors, and sun visor retaining clips. Door hinges and door check mechanisms will be inspected, and the hood and trunk release mechanisms will be exercised and their correct operation verified. The spare tire should be removed and both the front and rear internal structure of the car inspected for the presence of repaired accident damage. The condition of the spare as well as the presence of a tire air compressor and factory tool kit should also be noted. The battery area should be inspected for corrosion, particularly 914's and all 356, 911 and 912 models, especially those where a vented battery has been installed without the vent hose being installed and/or connected. The level and state of charge of battery electrolyte should be checked, as should the output of the alternator under load.
While in the trunk compartment of models so equipped (356, 911, 912, 914), brake fluid level and condition should be checked, as should any signs of leakage, particularly on the brake booster. Dirty brake fluid may be taken as a sign that the vehicle has been under-maintained, and test kits are available to chemically determine if there is moisture present in the brake fluid which can cause internal damage to brake hydraulic components.
Although the road test will have given the tech an idea of the condition of the suspension components, a so-called bounce test of the shock absorbers will be performed prior to placing the vehicle on a hoist. The bumper or a fender (not recommended on the aluminum-fendered 928 series) is depressed with the hands and the vehicle is allowed to return to its normal HEIGHT, with the oscillation being dampened out in no more than one or one-and-one half cycles, and the freedom of movement of the suspension not being interfered with by a "frozen" shock. On many Porsche models, the bounce test may not be conclusive, except to reveal a frozen shock, so the road test and later visual inspection for signs of leakage become more critical in locating a bad shock. In some cases, it is not unusual for original equipment Porsche shocks to last 100,000 miles, so mileage since the shock was last changed is a consideration as well.
When the car is placed on a hoist, wheel bearing play at all four wheels should be checked. The wheels and tires should be inspected for condition and tread depth, which should be noted on the inspection report. Tire wear patterns should be checked for signs of imbalance, alignment, or suspension problems. All four wheels should then be removed. The percentage of brake lining remaining should be noted, as should the condition and thickness of the brake rotors. Uneven pad wear on the same axle may indicate a frozen, inoperative, or incorrectly assembled brake caliper. On models equipped with a brake proportioning valve (914, 928) the valve should be inspected for signs of leakage. Brake hydraulic hoses and metal lines should be inspected for condition along with any vacuum hoses connected to the brake booster. "Stainless steel" type brake hoses should be noted for replacement unless the date of installation is known, since it is not possible to visually inspect this type of hose. For this reason, many techs recommend against their use on anything but cars that are driven exclusively on the track and where the lines are replaced on a regular basis.
Any protective undertrays should be removed and steering rack leakage or boot deterioration should be noted, as should ball joint or, -- on the 356, king and link pin, -- wear. Broken ball joint or tie-rod end dust boots should be noted, as should any signs of wear or looseness in the suspension or steering linkage. Stabilizer bar bushings and mounts should be inspected., particularly the rear stabilizer bar mounts on the 911 series, which are prone to cracking.
The floor pan itself should be carefully inspected for signs of corrosion, accident damage, or repairs. Many buyers, for example, would prefer not to acquire a car and then discover that it had been "sectioned", or made out of two or even three other cars whose pans have been welded together. While pan replacement is not unusual, particularly on the older models that were built prior to the introduction of corrosion-resistant steel in 1975, the quality of the repair can be a major factor in determining resale value.
The fuel tank, pump, and hoses should be checked for condition and any signs of leakage. The tank should be inspected for any damage such as might occur if something had been run over. The exhaust system should likewise be checked for any signs of damage, leakage, or corrosion. Heat shields, mufflers, manifolds, heat exchangers, pipes, hoses and all other exhaust system components should be inspected. The absence of any required emission control equipment should be noted, as should the condition of exhaust clamps, brackets, and hangers. Heater valves, hoses, and cables should also be checked.
The transmission fluid level should be checked, as should the transmission itself for any signs of leakage. Failed constant velocity joint boots and shift rod boots should be noted. The underside of the engine should be checked for any signs of fluid leakage and the type of fluid noted. Engine and transmission rubber mounts should be inspected for sagging or cracking. 944 and 924S series engine mounts should be checked for the proper HEIGHT dimension to insure that they have not failed internally. The oil pan and crankcase should be checked for any signs of accident damage.
Engine oil level and appearance should be checked, although with modern detergent oils it is difficult to visually gauge condition since the oil becomes "dirty" very quickly; this only indicates that the oil is doing its job by suspending contaminants rather than allowing them to remain in the lubricating system. The engine compartment should be inspected for any signs of fuel, oil, or coolant leakage, and for any deteriorated or missing rubber parts, including the engine compartment seal which runs around the perimeter of the compartment in air-cooled models. If this seal has been omitted, engine overheating and damage can occur. If the car is liquid-cooled, coolant level and condition should be checked. Using a hydrometer for the purpose, it is possible to tell to what temperature the coolant will offer freezing protection. A high number or the presence of contamination may indicate that the coolant is in need of changing. Severe contamination, commonly referred to as sludge or mud, in a 944 may indicate a failed oil-water intercooler seal.
The oil reservoir in air-cooled 911 models should be inspected for condition and signs of leakage, particularly around the oil level sending unit and on all of the oil lines leading to the reservoir. On models without self-adjusting valves, the valve covers may be inspected for any indication that they have been removed in the recent past, and for signs of leakage. If the valve covers do not appear to have been off in quite some time, this, too, may be taken as a sign that the car's maintenance has been neglected. Both air- and liquid-cooled models of Porsches have numerous places from which oil can leak, so in the case of an engine which is covered with oil it is wise to clean the engine and run it for a period of time prior to verifying the location of any leaks.
The wheels should now be reinstalled in their original positions and properly torqued, the undertrays reinstalled, and the car lowered to the ground. The engine air filter element should be removed and inspected, as this will provide an indication of when the car was last serviced. One spark plug or a distributor cap may be removed for another indication. Of course, if the client has requested a compression test, all of the spark plugs will be removed.
The necessity for a compression test during a pre-purchase inspection is a subject on which experts may rightfully disagree. Because additional expense over that for the inspection is involved, some buyers like to reserve it only for cars which have passed their other tests, or if there is a question generated by sluggish performance, a rough idle, or uneven cranking when the engine is being motored by the starter. When a weak cylinder comes up, the starter will noticeably speed up, except in the case of a 944 that has sheared a timing belt, where the starter turns faster on every cylinder. Even in that case, the difference in sound is noticeable to an experienced tech, although here the problem is more obvious since the engine also won't run. A less expensive alternative to the dynamic compression test, where a gauge is used to actually measure the compression in each cylinder, is a relative compression test which uses an engine analyzer to electronically establish relative compression values for the cylinders or which shorts out one cylinder at a time in what is known as a cylinder balance test and measures the rpm lost for each cylinder. What these tests will not reveal, however, is an engine in which all of the cylinders are worn equally and which have low compression across the board.
On models equipped with a toothed rubber timing belt, a visual inspection of both the belt and the oil seals behind it is recommended. If the belt has been recently replaced but the oil seals have not, the life of the belt will be drastically shortened, possibly even leading to belt failure significantly before the normally expected service interval. Any cracking or deterioration anywhere on the belt is cause for replacement, as would be a belt that has not been operating under the proper tension. While checking belts, the engine accessory drive belts should also be inspected, as should the water and power steering pumps for any signs of leakage. In some models, it is not possible to see the water pump without significant disassembly, so, as with the compression test, the cost will have to be weighed along with other factors.
Overall engine compartment cleanliness should be noted, with the theory being that a clean engine may be taken as a sign that the previous owner and his repair facility have taken some pride in the car. Unfortunately, this can also be a sign of an unscrupulous individual or business, especially if the engine has been sprayed with clear lacquer to give it a "like new" appearance, although even here appearances can be deceiving and the entire picture must be taken into consideration, including, but not limited to, the results of the inspection we have now completed.
When the inspection has been completed, the buyer should expect to see a written report of any mechanical discrepancies that were noted during the course of the inspection. The repair facility should also be able to provide estimated costs of repair for these items along with additional information on both the vehicle's overall condition and on how it compares to other similar vehicles with which they are familiar. The Porsche specialist can become, especially to the first-time Porsche buyer, the single most important source of information that is available.
Potential buyers need to remind themselves to not be discouraged by an apparently unfavorable inspection report, but to view it as a necessary part of "doing their homework" prior to making what is a major investment. All cars have problems, even brand new ones. In the case of used vehicles, some will definitely have fewer problems than others, and the idea is always to purchase the best vehicle (in overall condition) that your budget will allow, since repair costs, unlike the cost of the vehicle, are always paid in current dollars and are not depreciated. Many buyers use the inspection report as a negotiating tool to successfully effect a reduction in the vehicle's price or, in some cases, to aide in making the decision to reject a particular vehicle as not being suitable for their needs. Buyers who proceed with a purchase of an inspected vehicle do so with a far greater knowledge of what they have and are not subject to nearly so many "surprises" as is the individual who purchases a car at the swap meet on Sunday only to be told by his technician on Monday that the cost of the needed repairs exceeds the cost of the vehicle, not to mention what it will be worth after it is repaired.
On the other hand, if the needed repairs are known, in most cases they can be easily prioritized so that the costs can be spread out over a year or more, during which time the vehicle can still be driven and enjoyed while it is returned to optimum condition. This way, instead of taking away from the excitement of obtaining a new toy, the inspection report can be seen more as an agenda for returning one example of driving in its finest form to, well, its finest form. And, as is the case with the older Porsche models, many repairs can even be performed by the owner, thus resulting in additional savings.
12-19-2007, 07:41 PM
#3
Guru
Lifetime Rennlist
Member
Rennlist Small
Business Sponsor
Lifetime Rennlist
Member
Rennlist Small
Business Sponsor
The above list, while quite comprehensive, may need to be modified some as I believe this PPI is for a 996.
One aspect I would like to touch upon for the later cars is to have the oil filter removed and cut-open. This is to look for any swarf or debris that may be a sign of things to come. It would be well worth the cost of an oil filter and a little oil.
One aspect I would like to touch upon for the later cars is to have the oil filter removed and cut-open. This is to look for any swarf or debris that may be a sign of things to come. It would be well worth the cost of an oil filter and a little oil.
12-20-2007, 03:45 PM
#4
Drifting
Join Date: Apr 2003
Location: la la land | comin' back soon nyc
Posts: 3,351
Likes: 0
Received 2 Likes
on
2 Posts
The above list, while quite comprehensive, may need to be modified some as I believe this PPI is for a 996.
One aspect I would like to touch upon for the later cars is to have the oil filter removed and cut-open. This is to look for any swarf or debris that may be a sign of things to come. It would be well worth the cost of an oil filter and a little oil.
One aspect I would like to touch upon for the later cars is to have the oil filter removed and cut-open. This is to look for any swarf or debris that may be a sign of things to come. It would be well worth the cost of an oil filter and a little oil.
chris....
