groovzilla

all,

sold my C4 4 months ago because of health reasons...will explain later..

i had surgery and am healing up...since i must have a 993 in my life i found a good car - '95 polar silver/black..99K miles, service records/new clutch/brakes/etc...very meticulous owner.

** i am having the PPI done at a porsche dealer in northen calif. next week...when i told the service tech i wanted a leakdown test, he said he would recomend doing a compression test instead on the 993.

...the cost is an additional $250 for the compression test bringing the total PPI cost to $500

do you guys think the compression test is sufficient?...if i went with leakdown should the cost be about the same as a compression test??

thanks,
william

MarkD

I would ask him why he thinks a comp is better than a leakdown. And perhaps look for another shop to do the PPI... Personally, I would not go to the dealer for a PPI or much else on these cars.

Leakdown can pinpoint an issue if there is one. If you are going to do a PPI, both comp and leakdown should be done. My .02c
The same holes are used to do both tests.

Good luck with the purchase and post pics when you get it!

matt777

If I had to choose one I would go with the leak down test. I would think that a compression test would be another hour of work max. so I don't understand where the extra $250 comes from.

mkimber

I agree with Mark and Matt--leakdown over compression test, and I also don't know why there is a $250 bump. Seems high to me.

groovzilla

the cost of PPI is $250...the compression test is an additional $250 which will bring the total cost of PPI to $500

i have not asked the dealer what the difference in cost would be to have a leakdown INSTEAD of the compression test but i assume the leakdown would be a bit more expensive.

was wondering how much more time is involved to do a leakdown vs. a compression test so i know what type of cost to expect from the dealer

william

matt777

There shouldn't be much difference in cost between the two. With the leakdown you have to turn the engine by hand to get the piston at TDC for each cylinder test. With the compression test you're just cranking the engine over with the starter for each cylinder. What takes the most time is removing the wires and plugs and threading the tester in and out of each spark plug hole.

Steve Weiner-Rennsport Systems

William,

Glad to hear that you are on the mend and ready for another 993,...

I'd concur with the others: a leakdown test (if properly done) is FAR more useful than a compression test which tells me nothing.

I'd ask for a leakdown to be performed and the source of all leakage noted on the work order. The latter is really the key to this diagnostic procedure.