Cactus

I had a PPI done on a car I am about to purchase and the dealer (Fred Lavery Porsche in MI) and they did not do the compression check and appraisal like I asked for. Before everyone flames me for having it done at the dealer I did so because the mechanic is the only person that works on this car and I spoke to him in length about it andd i trust the seller is not hiding anything because I researched a previous car he sold. By the way the car is a 95 Carrera with 25,000miles and everything is bone dry. Just wondering how many times problems turn up compression related?

Martin S.

Mileage is so low...the car is dry, you trust the mechanic and the dealer....roll the dice. Chances are good that you'll roll a 7 on the first roll.

I bought my 993 with 17,000 miles...dry, ran swell, no smoke...I did NOT do the leak down and compression test. Almost 60,000 miles later, the car still runs strong. Just so you don't get flamed, just don't tell anyone that you did this. Right now only 20 people have viewed the post...quick, delete it while you still have a some reputation left!

TheOtherEric

Hard to say. Let me give you my experience. I bought a 993 despite poor compression numbers. One cylinder read 10% low, and there was a lot of variance in general. I later dyno'd the car, and it had the worst numbers I've ever heard of from a 993. While I can't say for certain that the compression CAUSED the low power, them's the facts.

My current 993 had solid compression numbers when tested. Based on some data logged runs, I also know the engine is stronger than that former 993.

YMMV.

Bearclaw

After paying for failed PPI's on THREE cars, I bought my current one without. You would think that after having findings on three previous attempts, that I would be more likely to have a PPI, but I was jaded. I saw this one at a Chicago Porsche dealer, they showed me 10 yrs. worth of service recs, told me what issues they cleaned up on it when they got it, and I bought it. It runs smooth and strong with great oil pressure, and I'm happy. They wanted about $900 for a PPI, and I felt like if I had farted around with inspections too much, they would have sold it to somebody else. That would have been too bad, because it's a great car and just what I wanted. "Roll the dice" is exactly what I told myself, sometimes you just go with your gut.

Cactus

I'm thinking a pampered car with 25,000 miles that still has 35% of the original front pad material hasn't been thrashed too bad right!

TheOtherEric

Oh, I forgot to mention, my car that had poor compression and low hp? It only had 35k miles!

Black930

PPI veeeeeeeeeeeeeeeeeeeeeery important.

Cactus

I think I got a half assed PPI that they just looked over things almost like a vehicle inspection. Fred Lavery Porsche sucks!

ientre9y11

I think the compression test and leakdown are the two most important things to do. They indicate whether there is a problem with the inside of the engine which is the most expensive thing to fix.

lthatch

If you cannot afford a PPI with a compression/leakdown, buy an aftermarket warranty for $3k, retain a lawyer for $1k to fight with the warranty company about your claims, or just buy a 2007.
My cranky 2 cents.

Terry Adams

I thought I saw Steve Weiner opine here (can't find his post), that a compression and leak down test would not identify worn valve guides or blocked SAI ports.

jimhsu

I am seeing folks talking about PPIs just this past week in terms of extra $500 or more just for the compression/leak down portion. I have not seen this kind of prices from the reputable shops around the country. Most of the ones have quoted an additional $1-200 for the compression/leak down, with PPIs totaling $2-400. Seems like it's mostly the dealers with the big prices.

mechanics I've talked to have all mentioned that they do one or the other, but not both compression and leak down. They all have personal biases for one or the other, citing their own experiences as the reasons.

My advice is to look for good independent shops that are Porsche specialists. A good reason to use the "Search" function on this forum: "inspection [fill in city name]" or PPI [fill in blank for city]" will usually pull up multiple links with folks who have asked the exact same question as you, and you can find shop recommendations without having to wait for days for all the answers to trickle in. (Man.... I sound so much like Ray S here....)

Svaha

Tony Callas demonstrated at his tech session last year a method by which the blockage of SAI ports could be easily detected. It involved monitoring the O2 sensor readings while turning on and off the secondary air pump. The SAI issue, while annoying, is less important than the condition of the valve guides.

Bearclaw

Something along the lines of "Certified PreOwned", another load of horsedump that the car co.'s whipped up to squeeze more dough out of used cars. Low compression and accident damage? Oh, that's not on the "CPO" checklist. But I digress...

TCallas

I usually don't expect much wrong with the PPI compression and leak down tests on a 993 but it is still a very, very important part of the whole picture. Just 3 weeks ago we located 2 bent valves on a 993 because the current owner had over revved the engine and failed to remember it during a PPI. Just as a general rule of thumb I would always perform a compression and leak down test on a PPI. Also a quick note that you normally cannot check the valve guide wear with a compression or leak down test and by the way, let's not forget that the SAI (Secondary Air Injection) problem IS from worn out valve guides so when you get a not so pleasing SAI test result at the oxygen sensors then chances are you have worn out valve guides.