KC_Michael

I'm considering purchase of a 2001 996 TT. Currrent owner is a stand up guy and told me he recently had an oil change done by someone whom, shall we say, was unqualified. The case was drained but guy didn't know about the sump tank or draining turbos. Refilled with around 8 quarts. Engine smoked like crazy, was shut off and car was flat bedded to mechanic. Intake was covered in oil. That was cleaned up as much as possible and MAF was replaced.
Question is: what permenent damage could have been done in the short time the engine was running with around 5 or 6 quarts overfilled? Is there anything I can do to get reassurance that there is no lasting effect from this maintenance misstep?
Drove the car yesterday and it seems fine. It's a really beautiful car but I don't want to buy a load of problems.
Thanks in advance for your thought on this matter

Michael

Macster

The effects from severe overfilling can be well, severe. One risk is the engine hydraulically locks up. If this happens you generally know about it right now. The engine suddenly stops running and usually to the accompaniment of what will prove to be very expensive sounds of engine parts breaking.

That the engine didn't suffer lock up is I think well, obvious.

Another risk is the 02 sensors or converters are damaged from the heavy dose of oil.

It may be just a coincidence but shortly (just hundreds) of miles after my 02 Boxster had its AOS go bad and in doing so practically flooded the engine with oil -- I might add I was told the engine suffered a mild (no damage) lock up while the tech was doing a compression test, a test I would have never authorized simply because of the risk it presented to the engine. After the AOS was replaced the engine ran fine save for the CEL. I after some effort traced this down to at least one bad (#1) O2 sensor.

However, the converters didn't exhibit any signs of trouble afterwards though one has now started to (well for the last 2 years or so) signaling a problem once in a while that indicates the thing is just wearing out. Understandable I guess given the car has over 250K miles on the original converters. And the other side has never once caused a CEL.

If the oil level has been corrected and the oil is of course an approved oil, or at least you know what oil was used and are ok with that, you can drive the car and see if there are any aftereffects from the overfiliing.

You must be thorough in this though. The process is the same as if the engine had not been overfilled with oil.

Briefly, visit the car with the engine cold. Be sure the A/C is off. Turn on the key, be sure all warning lights (including the CEL!) come on then go off when you start the engine.

You need to know what a healthy (or sick) Turbo engine sounds like as you let the engine idle and warm up.

Let it warm up as much as you can at idle. One sign of being warm enough is if you can check the oil level. (When I take my Turbo in for an oil change if the tech can't get to the car right away I see the engine has idled sometimes 15 minutes before the oil's hot enough to check and drain. How do I see this? Well, I have a data logger installed, one in each of my cars. The techs BTW know they're there and do not object.)

After the engine has idled a while then have the seller take you on a test ride. Teh route distance should be 15 miles or so and the route selected should give the driver a chance to demo the car doing what you will expect the car to do if you own it. Idle in traffic, tolerate stop/start traffic, cruise smoothly at blvd. and highway speeds; accelerate smoothly and strongly from idle to red line and then with a fast shift continue to pull good until the driver runs out well road. Obey all traffic laws!

Keep an eye on the gages: voltage, oil pressure, boost; for anything out the ordinary.

Back at the starting point you then take the car out as a driver. Follow the same route. Drive the car the same way.

What you want to do is give the engine time to manifest any problems, related to the oil overfill or something else. The DME constantly checks for misfires (under or over performing cylinders) and will turn on the CEL if it detect any misfires of note. This also gives the DME time to complete (maybe two times) all the readiness monitor tests that confirm (to the DME's satisfaction) the O2 sensors, the conveters, the misfire monitoring, knock sensing, fuel tank vent/vapor recovery systems (and maybe a few more) are all working and no problems were found.

Of course back after the now 30+ mile test ride/drive you once again listen to the engine, check that oil level, check the hot oil idle pressure and battery voltage and so on.

Also, this test drive gives any leaks a chance to make themselves known so a PPI with the car in the air can spot any leaks.

Chances are, based on what you wrote, the engine suffered no harm from the oil overfilling. But you need to be as sure as you can be. And you need to be sure the rest of the engine, its complement of sensors, and the car, all are in good working order.

Sincerely,

Macster.

Kevin

Michael, my suggestion is to pull the pressure hoses from the "Y" pipes and look for oil. If you have oil in them you need to clean all the hoses and intake ducting to the turbochargers. You would need to service the throttle body/clean the plenum. I would also pull and replace the spark plugs. If you have oil in the inlet pipes you have it in the intercoolers.

Don't be alarmed if you go to the 993TT forum, it is a FREQUENT event.. It is a BAD thing if the car is driven without correction but you wrote that the car was flatbedded. The only question that I would ask is why is the seller, using questionable service "wrenches" other repairs that should have been done???

uschoice

Macster,
Are you saying that the compression test was risky only because of the excessive oil, or just in general? Thanks

KC_Michael

Thanks very much to Macster and Kevin for your replies. A few follow up questions:
1) If inlet pipes have oil in them, should the intercoolers be removed and flushed out?
2) Would an emissions test tell me if the cats were damaged?
3) If either of the O2 sensors is damaged wouldn't a CEL appear?
4) Could I have one plug pulled to check for fouling and assume the other 5 are in similar condition? New plugs were just put in prior to this event and I hate to unnecessarily replace all six (if I buy the car).
5) On an unrelated issue, would you bother to do a leak-down test on a 2001 996TT with around 30,xxx miles? Mechanic doing the PPI said it was probably unnecessary.
Thanks in advance for your comments.
Michael

Kevin

Look, if you change the plugs you can do the LEAKDOWN right then and there. 5 extra minutes per cylinder. If the car doesn't have the updated 997TT coil packs they need it!

You will most likely be back in there IF you buy the car. Double labor and dollars spent on parts.

If you have oil in the inlet pipes >> ALL pipes and hoses and intercoolers need to be cleaned with DAWN dish soap and water.

Secondly, IF you are replacing the MAF and see all the oil, I would replace at a minimum the WIDEBAND O2's... You took 8 of the 9 lives out of them..

Macster

In the case of my '02 Boxster suffering from a bad AOS the compression test was not only risky but useless.

I didn't mention it in the the post but after I had given up on diagnosing the problem -- AOS failures were a bit rare then, circa early 2004, but I had nearly 80K miles on the car by then -- I called the service manager and detailed the symptoms. He said "AOS" and avoid running the engine.

So I called a flat bed tow truck -- from a company the dealer used -- and the car was picked up.

However, the two truck operator was next to clueless and unable or unwilling to park his truck to help get the car on it with a minimum of fuss so I had to start the engine to back the car out of the garage and then it got stuck in the snow and I had to rock the car to free it, all the while the engine was smoking like crazy.

Anyhow, with a pounding heart I got the car positioned then shut off the engine and the car was wenched up on the truck.

Then to learn than after doing this the tech then attempted a compression test with the risk to the engine really got me upset.

And the test in this case was unnecessary. With all that oil in the engine's cylinders the compression would have probably read good had the rings not even been present.

About all the compression test would have done is highlighted severe engine damage, cracked cylinder, head or piston or bent valves. However, the engine in spite of smoking heavily and running a bit rough wasn't running like it had anything seriously wrong internally.

I was never asked for permission to do the compression test. I dropped the car off with the request the AOS be replaced.

When I went to pick up the car and found the compression test had been done I objected to the charge and was told it was SOP or something, but I escalated to the service manager and he had the charge (over $300) removed from the bill.

The second time the AOS failed -- it just so happens near this same dealer -- when I dropped the car off -- had it flat bedded again this time from over 90 miles away -- I wrote on the envelop that I put the key into and then into the drop box "DO NOT START/RUN ENGINE!" and took pics of the thing. I also put a sign in the window and took pics. I wanted to take no chances this time.

When I called the next day about the car the service manager told me the techs had used some powered lift to pick up the car by its wheels (rear or front I do not know) and moved the car into the service bay without having to start the engine. I've seen these gizmos they're handy to have if a car won't or can't start/run. Saves risking your mechanics getting hernias from having to push a heavy old car around.

Sincerely,

Macster.

PorscheDoc

Is this the 996TT up in St Joe?

Macster

If you have not bought the car I'd insist all possible collateral damage from the oil overfilling be taken care of.

The problem is the owner/seller is very unlikely to wan to do this.

But this includes having the intake system thoroughly cleaned.

I would have the plugs replaced. Whether to have the coils done at this time...

The current owner/seller is unlikely to want to replace the coils absent any signs (CEL and misfire error codes) the coils are bad. Now maybe the tech doing the plug change will inspect the coils and based on their condition advise replacement. Hopefully this work will not be done at the same place that did the oil change...

However, I note Kevin says the original coil packs should be replaced with the new 997 coil packs, that's worth something. But to get the seller to agree to pay for this absent any clear signs the coils need replacing...

For the sensors, the Turbo has wide-band O2 sensors and they may be more at risk of damage from being doused with oil from a severe overfilling.

To replace or not?

That is the question.

The problem is if they are not replaced you risk having to replace them after you buy the car should they signal they need replacing.

But if there is no sign from the engine (DME) the sensors are acting up again the owner/seller is not going to spring for new ones...

As for the converters, the DME monitors the converters continuously for proper operation (ability to store oxygen) and in fact continuously checks for proper operation of the O2 sensors, and other systems.

If you subject the car to a thorough test ride/drive -- and I covered this in an earlier post -- if after the test ride/drive if the CEL remains off the odds are very high the the sensors/et al are ok.

For now.

There is the possibility the sensors/converters have suffered some degradation that can lead to premature failure.

It is unlikely absent any clear signs the sensors/converters are bad the seller will pay to replace these. THe sensors are expensive enough, the converters are even more expensive. (For my 02 Boxster a new factory sourced converter costs over $1000 and there's a couple of hours labor to remove the old one and install the new one.)

If the vehicle must comply with some emissions tests/requirements in your area having the car tested *before* buying the car to ensure that not only did your test drive turn up nothing amiss the car/engine actually passes emissions is a very good idea. The vapor recovery/tank vent system may be screwy.

My tech friends tell me a compression/leak down test is not needed. While the engine is running the DME constantly monitors each cylinder's contribution to the engine's total output and if it finds an under (or over) performing cylinder the DME will flag an error (misfire), turn on the CEL, and store one or more appropriate error codes.

A compression test may not be able to tell you if a valve spring is broken, or there's a collapsed lifter or something like that.

The engine needs to be run, the car driven, subjected to a thorough test ride/drive to give the engine from a cold start, through idle, warmup, steady state running, hard acceleration, coast down, and so on to manifest any problems. This also subjects all sensors from the coolant, intake air temp, knock sensors, and MAF and other systems like the throttle, injectors, fuel pump and so on to a variety of operating conditions which if there's a problem will have the CEL on or the engine acting abnormally, smoking, ticking, or in other ways showing it is unhealthy or there's a problem.

This test drive/ride also gives the engine and any fluid containing systems a chance to show any leaks.

It also gives you a chance to check the steering, braking, handling, and so on.

Now I can't recall if anyone brought this up, but that fact the owner had the car serviced at a place that totally screwed up something as simple and yet as important as an oil change... What other sub-par servicing has this car been subjected to...what other corners has this owner cut with this car?

I hate to say it, but maybe you need to consider another car?

Sincerely,

Macster.

iJeremy

Karl - Car just came to me for PPI, spoke with Michael about the need to remove and thouroughly clean intercooler's, pipes, etc. MAF was already replaced, PIWIS shows O2's reading correctly as of now, no misfires, etc - spoke to original owner about the need to pull plugs and investigate. Not sure how long she was actually driven after the over-fill but was told it was extremely brief before being flatbedded to my shop. This isn't the St Joe twin. Car is on the rack now being looked over.

Kevinmacd

Where does 6 extra quarts go. The tank can't hold the 8 left and the 6 new.. If they drained the crankcase that's not much more then a quart!

Dock

Good question.

Macster

The times I've changed my Turbo's oil there was more than a quart of oil in the crankcase. Not 6 quarts though, I grant you. Roughly I'd estimate between 2 and 3 quarts came out of the crankcase.

The extra oil fills up the free space in the oil tank which probably interferes with the vapor removal/crankcase ventilation process.

It probably also increases the amount of oil vapor in the crankcase fumes.

This vapor, or even some oil in liquid form (at least in this case), of course got routed to the engine.

Sincerely,

Macster.

jpflip

There are too many TT on the market today to stop your choice on a car that can be , on a long or short term, a problem. Look around, Ebay, cars.com etc, it is amazing the prices you can found....

jeffrh

i know someone had the same thing happen (didn't drain turbos). Lots of smoke. Had to clean it up and o2 sensors had to be replaced. Ran fine otherwise.