3.2 compression & leakdown question
 

What do these numbers mean?

compression 170 - 180 in all cylinders

leak down 30-38%

car smokes on start up and when cold if driven infrequently.

Thanks

Leak down done cold or Hot? Where was leak audible ... intake, exhaust, or breather?

If the tech or mgr didn't tell you, you didn't get your money's worth, and they are just after your wallet!

Smoking on startup is unrelated to engine general condition or wear!

The numbers you have quoted are incomplete and not compatible.
First leakdown is quoted per cylinder. The same as a compression test.
This leakdown test is used to determine where the engine is losing compression and make it part of the report to the customer.
If the compression test did indeed show 170 to 180 psi in all cylinders, there would be no need for a leakdown test.
170 to 180 is a healthy street engine.
You simply don't get a test with these numbers.

Yes, there were specific compressions for each cylinder in that range. The leak down is designated CLT which I assume is cold leakdown test. I'm wondering what leakdown is normal for say new/rebuilt, acceptable, or worn... I'm assuming that cold leakdowns in the 30-38 for all cylinders indicates moderate to significant wear. Maybe a valve job is in the near future for this car?

Brent,

Please see this thread for further discussion on the same question:

http://forums.pelicanparts.com/porsche-911-technical-forum/361181-compression-leak-down-give-very-different-results.html