Originally Posted by Gtxxjon
To whom are you referring John.

Are testers NOT allowed to wear make-up??? spank

I've been an engineer mechanic for over forty years and NEVER done a leakdown test... wrench
What does it prove?
Compression is being lost past the rings and valves and/or the head gasket.
A good mechanic would know if there is a problem by the signs?

We always know when an engine is making good power, when its worn out and ready to BLOW! drive
The trick is, knowing when to make the LAST run before this happens... fan


A leak down tester is a great tool to diagnose something before it gets worse. I'll use my small block as an example. Car was running fine, ran a new best of 10.54 just a few weeks before I did a leak down and compression test just as a health test. I found 2 cylinders with leaky exhaust valves that amounted to about a 35% leak down number, the good cylinders averaged 3%. So off with the heads, new hardened exhaust seats and now the whole motor averages 3% leak down. I haven't beat that new best ET yet but I have added about 80lbs of interior back and my MPH has gone up so its making more power. I guess I could have just waited until it was backfiring from trashed exhaust seats but the leak down test seemed like a good idea.

With a marked balancer its about a 10 minute test and can give you some great info to keep you from chasing your tail.

68 Barracuda Formula S 340