Looking at 88 S4 with A/C Issues...questions...
02-14-2010 | 05:43 PM
#16
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If the A/C has leaked out all the freon legally they must check and lind the leak and fix it BEFORE just adding more. Also note it is possible for the compressor to be leaking and need to be replaced. If you are really unlucky the A/C core hidden in the heater box behind the dash might need to be replaced and that is much labor...
02-14-2010 | 05:48 PM
#17
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From: Greensboro, NC
If the A/C has leaked out all the freon legally they must check and lind the leak and fix it BEFORE just adding more. Also note it is possible for the compressor to be leaking and need to be replaced. If you are really unlucky the A/C core hidden in the heater box behind the dash might need to be replaced and that is much labor...
I am dubious to be sure...
Michael
02-14-2010 | 06:15 PM
#18
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From: ft lauderdale
02-14-2010 | 06:43 PM
#20
Drifting
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From: Davidsonville, MD
Most of those "compatible" products are little more then snake oil and many contain propane or some other flammable gas.
When I finally took the time to get my A/C running properly, there was no real difference between R-134A and R-12. But "finally taking the time..." entails more work then many shops and individuals are willing to perform.
Although it's true that an R-134a molecule is smaller then an R-12 molecule, leakage at any joints should not be a concern if the O-rings were replaced. All of the fittings on the 928 are threaded. Go compare them to a modern Ford that uses those quick connect style fittings which allow parts to move and wear each other down and cause leaks.
I think that the main problem area around the compressor is where the hoses attach the fitting blocks on the compressor, or the O-rings that seal the fitting blocks to the compressor (which probably get ignored.) It's difficult to hold the compressor still and get the hose fittings tight enough, and even if they are, unless they're positioned perfectly, the hoses are going to have to move some which can loosen them. The other problem of course is that those fittings are on top of the compressor and not accessible while it's on the car. This problem is amplified because new hoses are incredibly stiff and difficult to manipulate.
One of the perks of Porken's timing belt set-up is that the air pump bracket is nowhere near as bulky as the factory equipment. Air pump removal/installation is much easier as a result. With the air pump out of the way, the hoses on top of the compressor are accessible and you can get a wrench on them to make sure they're tight. I was able to get a few extra turns on mine with the air pump out of the way.
When I finally took the time to get my A/C running properly, there was no real difference between R-134A and R-12. But "finally taking the time..." entails more work then many shops and individuals are willing to perform.
Although it's true that an R-134a molecule is smaller then an R-12 molecule, leakage at any joints should not be a concern if the O-rings were replaced. All of the fittings on the 928 are threaded. Go compare them to a modern Ford that uses those quick connect style fittings which allow parts to move and wear each other down and cause leaks.
I think that the main problem area around the compressor is where the hoses attach the fitting blocks on the compressor, or the O-rings that seal the fitting blocks to the compressor (which probably get ignored.) It's difficult to hold the compressor still and get the hose fittings tight enough, and even if they are, unless they're positioned perfectly, the hoses are going to have to move some which can loosen them. The other problem of course is that those fittings are on top of the compressor and not accessible while it's on the car. This problem is amplified because new hoses are incredibly stiff and difficult to manipulate.
One of the perks of Porken's timing belt set-up is that the air pump bracket is nowhere near as bulky as the factory equipment. Air pump removal/installation is much easier as a result. With the air pump out of the way, the hoses on top of the compressor are accessible and you can get a wrench on them to make sure they're tight. I was able to get a few extra turns on mine with the air pump out of the way.
02-14-2010 | 06:46 PM
#22
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From: Stockton, CA
lots of variables that could cause poor AC function...however the good news for you is you are only 25 miles away from Precision Motorwerks in Anaheim and Greg "Doc" Brown who can fix anything related to 928's....
02-14-2010 | 07:17 PM
#23
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From: Greensboro, NC
I should see if Greg can do a PPI and also diagnosis for the AC.
Thanks!
Michael
02-14-2010 | 07:20 PM
#24
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From: Southern Alberta, Canada
Its a wonder that a company like NAPA would be permitted to sell 'compatible' products if they're going to contaminate commercial service machines. I also read on this forum of a newer product coming to market for new vehicles to add more confusion as to what gas to use.
BTW when I replaced my a/c compressor, hoses, rxr/drier, O rings and expansion valve R134a was used to re-fill the system at a commercial GM service centre
It works well.
BTW when I replaced my a/c compressor, hoses, rxr/drier, O rings and expansion valve R134a was used to re-fill the system at a commercial GM service centre
It works well.
02-14-2010 | 07:34 PM
#26
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From: Greensboro, NC
I'm not worried about an R134a conversion from R12. If it's done correctly and the compressor works, it should be a non issue. If it's done incorrectly then it's far worse on the environment than R12...it's all about (as many said) proper o-rings, seals and recovery....
Michael
Michael
02-14-2010 | 09:20 PM
#27
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From: ɹəpun uʍop 'ʎəupʎs
Michael,
If the owner says that it worked fine after a re-gas, then ask him/her to have it re-gassed so you can verify that it does indeed blow cold once the engine has warmed up, *before* you spend money on a PPI.
Otherwise, I'd knock about $3k off the asking price of the car for just the AC issue. That would be a fair assessment of how much it costs to go through the AC system and fix any problems like leaving refrigerant, leaky vacuum actuators, compressor rebuilds, new o-rings etc.
Frankly, if you're paying someone to do the work, it may well cost more than $3k for a full AC system refurb, however with a 928-familiar mechanic, diagnosing the actual problems with the system can bring the cost down (like identifying *which* vac actuators are faulty before needlessly pulling the dash out of the car).
This is the kind of item that you can use as a negotiating point before committing to a PPI.
Don't get into the habit of using PPI's to find all the problems with a car before negotiating price - by then the seller knows you've committed dollars and will be less flexible, as they know that you're a buyer who now has a vested interest in buying the car to "recover" the money spent on a PPI.
Lastly, I know many would disagree with this statement, but from a purchase point of view, I don't care when the TBWP job was last done. Sure, finding a car with a proper service history at all mileage/time intervals is nice from a re-sale point of view, but focussing on the TBWP job is less important than other maintenance items like rubber hoses, seals, filters, fluid changes and other indications that the car has been correctly cared for and won't have excessive engine wear or leaks. As long as the car runs, the timing belt can be replaced by you after purchase.
Instead I prefer to make sure that the TBWP job is done correctly to my satisfaction by a 928-familiar mechanic. As an example, my 87 I bought last year had a TBWP job only 18 months and 10k miles prior. When I checked, belt tension was low, the belt tension warning system had been defeated, the tensioner was empty of oil and had not been rebuilt, and the important plastic bushings on the tensioner arm had not been replaced (one was cracked, and they were the old-style black ones) - most non-specialist mechanics just do not have the knowledge required to do this job properly. I would include Porsche dealers among the "non-specialist mechanics" as very few of them have a 928-trained mechanic on team these days.
If the owner says that it worked fine after a re-gas, then ask him/her to have it re-gassed so you can verify that it does indeed blow cold once the engine has warmed up, *before* you spend money on a PPI.
Otherwise, I'd knock about $3k off the asking price of the car for just the AC issue. That would be a fair assessment of how much it costs to go through the AC system and fix any problems like leaving refrigerant, leaky vacuum actuators, compressor rebuilds, new o-rings etc.
Frankly, if you're paying someone to do the work, it may well cost more than $3k for a full AC system refurb, however with a 928-familiar mechanic, diagnosing the actual problems with the system can bring the cost down (like identifying *which* vac actuators are faulty before needlessly pulling the dash out of the car).
This is the kind of item that you can use as a negotiating point before committing to a PPI.
Don't get into the habit of using PPI's to find all the problems with a car before negotiating price - by then the seller knows you've committed dollars and will be less flexible, as they know that you're a buyer who now has a vested interest in buying the car to "recover" the money spent on a PPI.
Lastly, I know many would disagree with this statement, but from a purchase point of view, I don't care when the TBWP job was last done. Sure, finding a car with a proper service history at all mileage/time intervals is nice from a re-sale point of view, but focussing on the TBWP job is less important than other maintenance items like rubber hoses, seals, filters, fluid changes and other indications that the car has been correctly cared for and won't have excessive engine wear or leaks. As long as the car runs, the timing belt can be replaced by you after purchase.
Instead I prefer to make sure that the TBWP job is done correctly to my satisfaction by a 928-familiar mechanic. As an example, my 87 I bought last year had a TBWP job only 18 months and 10k miles prior. When I checked, belt tension was low, the belt tension warning system had been defeated, the tensioner was empty of oil and had not been rebuilt, and the important plastic bushings on the tensioner arm had not been replaced (one was cracked, and they were the old-style black ones) - most non-specialist mechanics just do not have the knowledge required to do this job properly. I would include Porsche dealers among the "non-specialist mechanics" as very few of them have a 928-trained mechanic on team these days.
I've scoured through the threads on A/C and on PPI and in the FAQs and there is a lot to digest...
The car I'm looking at has had all recent service and has 70K. The steering rack has been replaced; the TB/WP was done 3 years ago at about 63K Miles. Checking on motor mounts and also fuel lines.
Unfortunately the current owner stated that the AC does not blow cold at the moment. For the last few years he has recharged it as it got warmer in LA (spring) and it was fine through the summer then would go warm the following spring.
When the car was checked he was told the compressor is fine and sounds to me like a leak somewhere in the AC lines. Not sure if there is rear air (checking the car next week).
Realistically I know this is a very common problem and not an easy one. How much should I budget (and negotiate) to have the AC fixed? Is it R12 or R134? If R12 should I also have the system converted or stay with R12?
Thanks in advance,
Michael
The car I'm looking at has had all recent service and has 70K. The steering rack has been replaced; the TB/WP was done 3 years ago at about 63K Miles. Checking on motor mounts and also fuel lines.
Unfortunately the current owner stated that the AC does not blow cold at the moment. For the last few years he has recharged it as it got warmer in LA (spring) and it was fine through the summer then would go warm the following spring.
When the car was checked he was told the compressor is fine and sounds to me like a leak somewhere in the AC lines. Not sure if there is rear air (checking the car next week).
Realistically I know this is a very common problem and not an easy one. How much should I budget (and negotiate) to have the AC fixed? Is it R12 or R134? If R12 should I also have the system converted or stay with R12?
Thanks in advance,
Michael
02-14-2010 | 09:53 PM
#28
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From: Greensboro, NC
Michael,
If the owner says that it worked fine after a re-gas, then ask him/her to have it re-gassed so you can verify that it does indeed blow cold once the engine has warmed up, *before* you spend money on a PPI.
Otherwise, I'd knock about $3k off the asking price of the car for just the AC issue. That would be a fair assessment of how much it costs to go through the AC system and fix any problems like leaving refrigerant, leaky vacuum actuators, compressor rebuilds, new o-rings etc.
Frankly, if you're paying someone to do the work, it may well cost more than $3k for a full AC system refurb, however with a 928-familiar mechanic, diagnosing the actual problems with the system can bring the cost down (like identifying *which* vac actuators are faulty before needlessly pulling the dash out of the car).
This is the kind of item that you can use as a negotiating point before committing to a PPI.
Don't get into the habit of using PPI's to find all the problems with a car before negotiating price - by then the seller knows you've committed dollars and will be less flexible, as they know that you're a buyer who now has a vested interest in buying the car to "recover" the money spent on a PPI.
Lastly, I know many would disagree with this statement, but from a purchase point of view, I don't care when the TBWP job was last done. Sure, finding a car with a proper service history at all mileage/time intervals is nice from a re-sale point of view, but focussing on the TBWP job is less important than other maintenance items like rubber hoses, seals, filters, fluid changes and other indications that the car has been correctly cared for and won't have excessive engine wear or leaks. As long as the car runs, the timing belt can be replaced by you after purchase.
Instead I prefer to make sure that the TBWP job is done correctly to my satisfaction by a 928-familiar mechanic. As an example, my 87 I bought last year had a TBWP job only 18 months and 10k miles prior. When I checked, belt tension was low, the belt tension warning system had been defeated, the tensioner was empty of oil and had not been rebuilt, and the important plastic bushings on the tensioner arm had not been replaced (one was cracked, and they were the old-style black ones) - most non-specialist mechanics just do not have the knowledge required to do this job properly. I would include Porsche dealers among the "non-specialist mechanics" as very few of them have a 928-trained mechanic on team these days.
If the owner says that it worked fine after a re-gas, then ask him/her to have it re-gassed so you can verify that it does indeed blow cold once the engine has warmed up, *before* you spend money on a PPI.
Otherwise, I'd knock about $3k off the asking price of the car for just the AC issue. That would be a fair assessment of how much it costs to go through the AC system and fix any problems like leaving refrigerant, leaky vacuum actuators, compressor rebuilds, new o-rings etc.
Frankly, if you're paying someone to do the work, it may well cost more than $3k for a full AC system refurb, however with a 928-familiar mechanic, diagnosing the actual problems with the system can bring the cost down (like identifying *which* vac actuators are faulty before needlessly pulling the dash out of the car).
This is the kind of item that you can use as a negotiating point before committing to a PPI.
Don't get into the habit of using PPI's to find all the problems with a car before negotiating price - by then the seller knows you've committed dollars and will be less flexible, as they know that you're a buyer who now has a vested interest in buying the car to "recover" the money spent on a PPI.
Lastly, I know many would disagree with this statement, but from a purchase point of view, I don't care when the TBWP job was last done. Sure, finding a car with a proper service history at all mileage/time intervals is nice from a re-sale point of view, but focussing on the TBWP job is less important than other maintenance items like rubber hoses, seals, filters, fluid changes and other indications that the car has been correctly cared for and won't have excessive engine wear or leaks. As long as the car runs, the timing belt can be replaced by you after purchase.
Instead I prefer to make sure that the TBWP job is done correctly to my satisfaction by a 928-familiar mechanic. As an example, my 87 I bought last year had a TBWP job only 18 months and 10k miles prior. When I checked, belt tension was low, the belt tension warning system had been defeated, the tensioner was empty of oil and had not been rebuilt, and the important plastic bushings on the tensioner arm had not been replaced (one was cracked, and they were the old-style black ones) - most non-specialist mechanics just do not have the knowledge required to do this job properly. I would include Porsche dealers among the "non-specialist mechanics" as very few of them have a 928-trained mechanic on team these days.
I think another key also in the TBWP "equation" is WHO did the job and did they follow up with the retension...
Michael
02-14-2010 | 10:23 PM
#29
Burning Brakes
Joined: Oct 2008
Posts: 972
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From: Palo Alto, CA
Actually don't, but "freeze 12" is propane. Literally. Put that in and the next time your A/C leaks, kaboom, nice knowing you.
The rest of this post may be recap, I just skimmed the thread.
Stick with R-12, it can still be had. Alternatively, you can go 134a. Later model cars work fine with either, I think pre-85 cars have weaker fans that don't pull air as well through the A/C condenser, so some are dissatisfied with 134a in the earlier cars. Debate rages on the cause, but ultimately it probably comes down to how dry the system is before it is charged. A good strong vacuum pump on it for a day prior will leave you with a system that is dry as a bone. Then you can load whatever you want into the system.
A second piece of advice (if you DIY) is to do the conversion to 134a. You will have all new o-rings and easier fittings to work with, and then if you get a tap for the refrigerant can that comes out the side rather than the factory fitting at the top, you can tap r12 and run it into your system despite the 134a fittings. Be aware that this could cause confusion to any future owner, so point out if you have done this, and I don't believe the refrigerants are compatible in large amounts. If you don't plan to ever sell the car, then don't worry about it and make yourself happy.
If you go professional, good luck. I tried to find people to work on it, noone would touch it, though that was in MD, not in CA. CA is a place more used to exotics, so it may be easier out here. If you do find someone, be prepared to be separated from your bank account. Also pray that the guy knows what he is doing with the 928, or you will be paying even more when you have to redo it yourself.
Good luck!
02-14-2010 | 10:45 PM
#30
Thread Starter
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Joined: Jan 2010
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From: Greensboro, NC
GOOD GOD KILL IT WITH FIRE!!!!!
If you go professional, good luck. I tried to find people to work on it, noone would touch it, though that was in MD, not in CA. CA is a place more used to exotics, so it may be easier out here. If you do find someone, be prepared to be separated from your bank account. Also pray that the guy knows what he is doing with the 928, or you will be paying even more when you have to redo it yourself.
Good luck!
If you go professional, good luck. I tried to find people to work on it, noone would touch it, though that was in MD, not in CA. CA is a place more used to exotics, so it may be easier out here. If you do find someone, be prepared to be separated from your bank account. Also pray that the guy knows what he is doing with the 928, or you will be paying even more when you have to redo it yourself.
Good luck!
