CornerCarver

Hello all.

For those of you that have gone the PPI route when purchasing a 996 TT; did you have a compression/leakdown performed? If so, how many hours were you quoted?


Thanks

Al

LVDell

The only one you really need to get done if you want to do either of them is the leakdown. The compression test is so inconsistent due to operator error and so many variables. And no, I have never had either done except on a race car purchase.

adam_

I did not have this done, however when I purchased the car had 17k miles, single owner and there were zero Type II over-revs. (There were a handful of Type I over-revs (like 20), and when the seller heard this he grumbled "I'll need to speak to my wife").

Is there anything about this car that raises suspicion? You might consider a 'staged' inspection- do everything up to the leakdown, then review results- and make the decision there on pass, accept or leakdown.


Time wise, I've heard 4-6 hours quoted. Since it involves removing each plug, definitely have new plugs put back in- even if you ultimately pass. (Perhaps work out with the seller they pay $x if you pass since they get the plugs done??)

GL

A

larry47us

I didn't do a leakdown when I bought my TT. The reason was the cost and the amount of information I would gain. The car is a 2001, and had 25K miles on it. When my indie drove the car, he pushed it pretty hard, and was pleased with the way it ran. He said that he could do a leakdown, but that on a Turbo, it's an expensive process. They need to drop the rear bumper and pull the turbos to reach the plugs. This involved a few hours of work, and in light of the way the engine ran, I didn't feel it necessary to throw that extra money away.

On air-cooled, early cars, I have ALWAYS done a leakdown. But, this is a different animal.

larry

SY6TTX50

I did not have it done either when I bought mine.

Kevin

If you folks are buying a car over 50 to 60K with multiple owners a LEAKDOWN test is salvation for your wallet. Bent valves and wrecked valvetrain = $15 to 28K repair bill. If you don't want the hassle, buy a aftermarket warranty.

The type 1 and type 2 overRevs will tell you alot. I have seen engines that have maxed out TYPE 2 overRevs!!!

I would also be pulling the oil filter and looking for metal.. Bits in the filter would be a deal breaker for me.

FYI Larry the valves in the GT3 and Turbo are tiny, the valve stem will bend easier than the previous air-cooled valves.

Macster

You have to be careful. In another section here someone posted of the engine logging a misfire error code with the flashing check engine light no less yet a leakdown (or compression) test didn't find anything out of the ordinary.

I know there's some reluctance to let go of these types of tests but with the modern engine controller that constantly checks for under (or over) performing cylinders and if one is found a misfire error code is logged and the check engine light is turned on, compression and leak down tests have dropped in usefullness.

I just spoke with a tech the other day that did a PPI on I believe a 996 GT3 and no compression or leakdown test is done.

However, the car was given a thorough road test by the tech and the tech knows how to drive the car to give the engine controller every chance of detecting any misfires or other error conditions.

Back at the service bay the tech hooks up a computer and reads among other things readings/derived values, test results that are used to make an intelligent decision of the engine's health.

For us laymen, being able to start a cold engine verify the check engine light comes on then goes off as the engine starts then let the engine idle and warm up and listen to it as it does so goes a long way to helping one make a judgement call on an engine's health.

After a substantial warm up during which the engine should emit/manifest normal engine noises -- for instance while a compression test or a leak down test won't ID a noisy lifter or even a broken valve spring your ears can hear the noises these emit -- then the car must be driven some distance (15 miles or so is a good number) -- I recommend the buyer ride along as a passenger during this first test drive so he can more completely focus/concentrate on the engine and the car's behavior -- and driven in such a way a variety of driving conditions are experienced. This gives the engine time to get fully up to temp and the engine controller time to run its longish tests to completion. It also gives the engine time -- if it is going to -- to manifest any misfire or other error conditions that the engine controller will detect.

After the test ride then the buyer takes the car out and following the same route and driving the car the same way more directly experiences the car and the engine. But this added miles driven gives the engine even more time to act up if it is going to and the engine controller more time to detect this and let you know by turning on the check engine light.

After this round of driving then the car needs to be examined from underneath looking for any fresh sign of fluid leaks (along with a bunch of things).

A compression test or leak down test is old school. They have their place in some instances. For instance a leak down test was taught to me as a diagnostic test to when an engine was suspected of being sick to possibly pinpoint where. Was the leaking cylinder leaking compressed air into the adjacent cylinder through a failed headgasket? Or leaking compressed air into the cooling system? Or into the oil system? Or past an intake valve, or exhaust valve. One listened very carefully at various locations to try to hear where the air from the sick cylinder was escaping too. If from a valve then a head job likely. A gasket maybe a head job but the head might be cracked or worse, the block might be cracked.

After the test ride and drive then the buyer (or his PPI rep) can certainly look at the oil filter element. This is better done after the test ride/drive so that if the engine oil was just changed *before* the test ride/drive if the engine is shedding bits of metal these will only appear after the engine is run some time.

Oh, when I bought my 03 Turbo I didn't have a PPI done. The car only had 10K miles on it and was in pristine condition. I confirmed the car's condition and did some more research on my own and found the car had had reasonable servicing by the first owner.

Also, the car was CPO'd and the dealer's service department peformed a pretty comprehensive inspection of the vehicle. The CPO paper work is several pages long and there are many checks/tests that are done to confirm the car meets with the CPO standards. Sure the dealer could have instructed the tech to skimp on this, even to lie. But if I thought I had any reason to suspect this instead of worrying about where to take the car to get a PPI done to ease my suspicions about the car's true condition, I would not have been at that dealer looking at cars in the first place.

Anyhow, as I said my check out of the car confirmed the car's condition and when it came time to check out the engine and see how the car drove, the engine sounded healthy from the get go and the car drove just fine.

It is your money and if you want a PPI to include a compression test or a leak down test, fine. But do give the car and the engine a thorogh road test both as a passenger and as a driver just in case.

Sincerely,

Macster.

Kevin

Alot of folks are buying the cars out of state.

A CPO does not indicate a car that the car has lived a sterile life. I have many customers that have purchased a CPO'd car that has been flashed. Adam (on this forum) can vouch about a dealer that sold a CPO'd car in his area that had a full blown engine kit.. You can't put all your eggs in the basket with the CPO'd vehicles. Disclaimer I bought my wifes 996TT CPO'd and there were some issues>>clutch related.

With that said, asking when the plugs were changed, if they don't know do the leakdown test and replace the plugs while your at it. If the car is high on the list you will sleep better with the leakdown test and new plugs. The fault that we are trying to catch is a bent valve from a missed shift. Usually 95% of the time it is a exhaust valve ( 2 per cylinder) Last year I can confirm a engine that had ZERO misfire issues, but later developed a camshaft deviation code. The engine had 2 cylinders that had bent valves.. Chicken or the egg?? The car was a recent purchase with not CEL history. The car had a PPI with no leakdown test done. As these cars age, and as they miles rack up, a leakdown test, plugs at a minimum is a sound investment.

If you are looking to buy a car from a private party ask him not to change the oil, or ask him how many miles is on the car. Guys with the threads about sick engines >> do you trust all the sellers and used car dealers?? Some of these engines are sick and are being passed to the impulse buyer. Installing 20W oil can mask a failing intake lifter for a PPI. Clearing the engine codes before a PPI will fool unwise tech of buyer that HOPES and believes that the tech is looking for out for his best interest. You see what you see when you do a PPI, you report on what you see.

CornerCarver

Thanks for everyone's thoughts. The seller went back on his word and gentlemen's handshake after we agreed on a price and took another offer in the midst of me scheduling a PPI. I believe I scared him with the fact that I wanted to have a thorough PPI performed, not just a once over at dealership while he waited in the lobby. I am not following how anyone purchasing a $40 to $50k used TT would even think twice about not investing in a thorough PPI.

Dock

I completely agree.

Hoosier_Daddy

Unfortunate you see it like that…

I understand you had some hardship; however, you first e-mailed me on 4/21 and didn’t see the car until 5/21. You were asked for a deposit on Sat 5/21 if you wanted the car for the price I agreed to sell if for... you wanted additional time… you still seemed somewhat reluctant to commit... I said okay - what else was I to do? You drove the car for 20 minutes and had every opportunity to place a deposit with me for the car – you choose not to do that.

As a side note… you were also somewhat slow to reply to my e-mails the day or two following regarding the car and your time-line which didn’t instill confidence in you as a buyer. I understand, it’s a big decision, however, the car was for sale and frankly, I am not involved in your decision making process. I also understand you were burned in the past, but I did not deserve your mistrust. (Evident by your false accusation in the above post)

Someone came out to see my car that was for sale and had money for deposit, made up their mind and agreed to by the car – that’s generally how it works; I am sorry you have sour grapes. Maybe next time you will be lucky enough to know what you want in a timelier manner. I don’t know whether you are trying to justify your indecision or not, but be that as it may -- your above post is poor form in anyone’s book.

The new owner will be very happy with the car and I wish you luck with your search.

Kevinmacd

There's always two sides to every story! Based on the response from the seller, I don't blame the seller for taking the deposit and selling. I think anyone would have done the samething.

CornerCarver

I apologize. I guess I am the anomaly as I've bought and sold over 20 cars throughout the years and have never asked when selling or provided a deposit when purchasing and I purchased all but one due to an unacceptable PPI. I did not mean to attack your character and I apologize, if my post came across as such. Yes, sour grapes were in effect for sure. I am sure the new owner will be very happy with the car and I look forward to seeing it at the local tracks. Good luck with your new car.