PPI with compression & leak-down testing?

I'm considering a '02 C4S that now has about 108500 miles on her. This is the same car that Rennlister ZRoadhouse owned and posted about for a few years after buying it from RocC4S over at 6SpeedOnline. It's still a nice looking car with all the mods (minus the black wheels) that were there in 2009. The car has my interest just as it did in 2014 when it was last for sale so I'm strongly considering coordinating a PPI with the seller. I took her for a drive yesterday evening and to me, everything sounded good, smooth idle, nothing gave me cause for concern. I listened for taps and knocks from the engine and there just weren't any discernable noises to my untrained ear. One of the shops I called today about a PPI asked a couple of questions that I have never been asked when calling other shops here in Austin or anywhere else: how many miles and will this car be a daily driver. Because of my answers, he then suggested that the car was becoming a high-mileage car (true) and he would suggest a compression test and possibly a leak-down test as part of the PPI. That's a first for me in my limited experience. While I heard no sounds from the engine that concerned me, I did note the tailpipes were pretty sooty, black even. I only note this because in the horror threads I've read about scored cylinders and such, I've always seen heavily sooted pipes BUT in combination with noises of concern. Of course, the soot could simply be from lack of cleaning and not indicative of anything mechanically. My questions are: I don't think this is a common set of tests for a PPI, or is it? Is it perhaps a good idea to do compression and leak-down testing on a car with 100k+ miles? Any thoughts on this?

Is a leak down test common for a PPI - no. Is it a good idea? Sure why not, it will give you more information about the engine. If you are about to purchase this car and you don't mind the extra expense, it may give you some additional peace of mind when it comes back normal. It will not guarantee you'll never have a problem. You are purchasing a 16+ year old car, it's a toy that will need regular maintenance (i.e. more money dumped into it)

^x2

Should be mandatory on an engine with that many miles to determine extent of wear to cylinders &/or rings etc.

We hear about scored/cracked cylinders a lot more than worn rings or valves. I think I'd ask for the cylinders to be borescoped before asking for a compression test. But I guess you can do both if you pull the plugs.

It was very common in the pre 96 models but anything after that with OBDII its probably not as common. If it passes the scanner test with no misfires, DTCs or pending fault codes, chances are high that the engine is sound.

For what it's worth I paid extra for those two tests to be added to my PPI and the knowledge that my engine passed with flying colors gives me at least some baseline confidence that if I continue to treat the engine properly I can keep those numbers for a good long while.

Not sure if this is included, but I would also want them to pull the oil filter and check oil, ahhhhhh if only.

@Apachechief: If you have full service history on the car from new, documenting regular oil change and fluid flush intervals, than a compression/leakdown is less critical. If you're at all unsure about how the car was treated, however, I'd recommend a full PPI + one or both of the procedures. Let me know if our Porsche tech in Austin can help. Thanks!

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!st step of a PPI should be pull the oil filter housing, depending on what you find it may be the last step saving a lot of money.

Hi all. Thanks for the replies and thoughts. The shop suggesting the compression and leak down tests is estimating 6 to 8 hours for the complete PPI which is 2x or more than what I'd expected and budgeted. But I get it, $1k, you know get a solid idea of what you're buying and have a baseline condition to move forward from. The other bit that's tripping me up is that the car apparently throws O2 sensor codes every few months, along the lines of the Pelican Parts thread: http://forums.pelicanparts.com/porsc...t-problem.html Now that I think about it, running rich could cause sooty pipes also... @Montychristo128 and @Byprodriver - This shop does pull an oil sample for inspection as a standard part of their PPI. @Butterson - I'm under the impression that the most effective borescope comes by entering the engine from the underside. Can you get a good read from the top of the cylinder? @InspectX - Unfortunately the service records were lost somewhere along the way before the CO took possession. CO does have all of his records. I've been able to piece together some history from forum posts and CarFax. :/

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6 to 8hrs for a PPI?

@ApacheChief: Did you already schedule the PPI + leakdown?

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Leakdown takes time Id rather a through the sump borescope vs leakdown