Leak down results, I was afraid of this!

[Skip Newsom]

I got the use of a leak down tool and here is what I found:
#1 20%
#2 6%
#3 8%
#4 7%
#5 6%
#6 7%

I knew something was up with #1, when I pull the plugs its always much darker than the rest... the car runs pretty well, a little bit of a miss at lower RPMs, but it seems to pull to redline happily. This is my first 911 so I don't have anything to compare it to...

The instructions with the tool say to perform the test on a cold engine due to dangers of injecting cold air into a hot engine (seems like when one is running at high RPMs that would be going on quite a bit anyway), Wayne's engine rebuild book says to perform the test with the engine warm.

Do you think I should check it warm too, is there really a risk???

[Rot 911]

I've always done my checks with the engine warm. I would recheck it warm. I would also do a compression test while you are at it. Also with the engine warm.

[Elombard]

I have a similar thing going on for a year. I try not to think about it. Runs great? I figure if I really tare it up before I get a chance to fix it 3.0 core motors are getting cheap enough to justify my laziness/cheap ness.

[ChrisBennet]

A leakdown test is not a definative test - good engines can have bad leakdowns and vice versa. You use it with other tests to get a true picture of what is going on. I would listen to find where the leaking air is going - out the valves or past the rings.
-Chris

[rcwaldo]

Test with a warm engine, not hot, but warm. Injecting cold air, especially 'wet' air from a compressor without a dryer installed, wont do the exhaust valve any good..

[Skip Newsom]

Thanks for the replies!!
I bought a Gunson Gastester a few weeks ago that I've wanted to use too, so looks like I have my projects for the day set!

It's clear, nearly dry and about 29 degrees in the Pacific Northwest this morning, looks like I get to go for a "warm up" drive... excellent!

I'll set the CO levels at 3K and idle, do a compression test, and leakdown while warm. I'll post the results...

[svandamme]

heat expands components, so you might get a better result on #1 once things have warmed up

if it runs good, i wouldn't worry to much about it, it's not like all cyllinders have 20% or more....
if you average your's , you have 9% which is not bad according to the book