I recently did a Pre Purchase Inspection for a local car the other day. Last time I did a PPI for this seller (on a previous 993TT that he owned), I swore I would raise my prices as the leakdown and compression tests take a long time on the turbo cars, lol…..of course I forgot about that until after I had set up the PPI. Oh well 🙂

A beautiful example of a 993TT. A PPI consists of a full inspection of every aspect of the car. Buyers love me, and sellers tend to hate me when I do a PPI, as I spend about 6 hours average on the cars and compile a written report along with about 50-60 pictures of the car. Typically you have 2 types of PPI. A basic PPI consists of the entire inspection, and the in depth PPI adds leakdown and compression tests to determine the health of the engine. Unfortunately, while you can give your undivided attention to a PPI to reduce risk of buying a used car and something failing, there is no super secret x-ray vision, nor can you predict the future of what might fail on the car.

In the air, a fairly clean underside 🙂 If this car has ever been driven in the rain, it really doesn’t show.

An example of a leakdown test. This test checks the condition of the valve’s ability to seal in the cylinder head. A bad leakdown would likely suggest worn valve guides or need for a valve job. 100psi of air is injected into the cylinder with it at TDC. An excellent engine will range from 2%-10% leakdown, a good engine 10-20%, and an engine in ok shape or needing a rebuild above that. Here you can see that this cylinder in particular is at 4% which is excellent.

Along with checking the car itself, other things you look for are: Complete tool kits, air compressors, spare tire, and a complete set of manuals.


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David Lessmann

June 10, 2011 at 7:12 PM

Looks like the pictures disappeared.


June 12, 2011 at 8:14 AM

Thanks David, should be working now!

David Lessmann

June 12, 2011 at 9:25 AM

Yep. They’re back. I passed the URL to this page to a friend of mine who’s looking to buy a used Porsche, and strongly suggested he call you up for a PPI.

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