![]() |
|
|
|
Registered
|
Compression test on '89 3.2 - waste of money?
Dear fellow Pelicans. I'm about to push the buy button on an '89 3.2. Drives flawlessly. No smoke, 100% clean engine, no visible leaks anywhere. Brown exhust pipe.
I've asked for a compression test, but the local mechanic (allegedly experienced porsche mechanic) consider it a waste of money. Do you concur? Edit: I meant leak-down of course! Last edited by Nux; 04-24-2017 at 02:29 AM.. |
||
![]() |
|
Registered
|
You can do a compression test without a leak-down. It's quick and cheaper than a leak-down. Obviously not as thorough, but can give you some data. I would agree with your mechanic, though, based on the fact that there is no smoke and runs smooth, a leak-down is likely not necessary. But have him pull the plugs and look at their burn color. If all consistent brown, it's good. Then checking compression is easy. If those values are consistent across all 6, you should be OK. My $.02. Good luck.
__________________
'87 Carrera (3.4L) w/Turbo, full-bay IC; front bumper aux oil cooler, etc. '07 Boxter |
||
![]() |
|
Registered
Join Date: Oct 2008
Location: Denver, CO
Posts: 3,494
|
You should get a compression test -- some 3.2 carreras (mine included) suffer from premature valve guide wear, which requires a top end overhaul to rectify. Compression test should clarify on this issue and a catalytic converter (if installed) would hide the telltale smoke. This can also be evidenced by excessive oil consumption (over a quart per 1k miles) even if no visible leaks.
|
||
![]() |
|
Registered
|
waste of money. Drive and keep smiling
Oops; failed to read properly. If considering to buy I would advice to do a leak down test. Hard to judge the condition in any other way being new to the car
__________________
80SC (ex California) Last edited by trond; 04-24-2017 at 09:56 AM.. |
||
![]() |
|
Registered
|
If it's just for your own peace of mind, go ahead. Heck, you have your cholesterol checked yearly, right? It's nice to know the numbers. But, yeah, unless you're diagnosing an issue, it's a waste.
__________________
72 911T 2.4 MFI 2017 Escape SE 2.0 turbo 2020 Honda Civic Touring Sport 1.6 turbo 10' Madone 5.2/17' Lynskey ProCross |
||
![]() |
|
Registered
Join Date: Jan 2006
Posts: 174
|
Quote:
An absolute must when buying an older car. If you don't and the engine has issues you have no one to blame but yourself. |
||
![]() |
|
![]() |
Registered
|
Quote:
__________________
72 911T 2.4 MFI 2017 Escape SE 2.0 turbo 2020 Honda Civic Touring Sport 1.6 turbo 10' Madone 5.2/17' Lynskey ProCross |
||
![]() |
|
Registered
|
Thanks for the reply guys - I've requsted the leak down. If it's good I guess I'll be very happy driving it home knowing it's in good working order.
|
||
![]() |
|
Registered User
Join Date: May 2016
Posts: 4
|
Quote:
|
||
![]() |
|
Registered
Join Date: Oct 2013
Location: Prescott, AZ
Posts: 1,062
|
Neither will a compression test. Both the leak down and compression tests can detect worn rings and valves that aren't seating properly.
__________________
1990 964 Coupe 1986 Carrera 3.2 Targa |
||
![]() |
|
Registered
Join Date: Jan 2003
Location: Langley,B.C.
Posts: 12,002
|
Quote:
A compression test will NOT show bad guides or worn valve stems. With bad guides a valve still seats properly, yielding good results. Also, if you have worn guides, your catalytic converter will not hide the smoke. It will still show out the tailpipe on decel. Compression and leakdown tests will show worn rings, worn intake or exhaust valve seat/valve head issues though, as well as bad head/cylinder seal-but you say engine is dry and this issues shows visibly. An engine with good compression and leakdown numbers that consumes excessive amounts of oil likely has bad guides and/or worn stems... Don't "run away" from the mechanic. Ask him why he thinks it is a waste of money. Brown exhaust pipe, not sure what brown looks like, it is very subjective. That said it never hurts to have the tests done because they can yield good information, just not about valve guides... Cheers
__________________
Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 Last edited by Jeff Alton; 04-26-2017 at 09:02 PM.. |
||
![]() |
|
Registered
|
I almost did NOT do a PPI on one of the P-Cars I was intending to buy, which had all the power and torque in the world, but it ended up with almost two dead cylinders, which I did not buy in the end.
|
||
![]() |
|
![]() |