racemechanic

I have just performed a leakdown test on an '86 944 engine with approx. 90,000 miles that I just purchased. Everything that I have seen says to do a leakdown test on a warmed up engine. Since this engine is out of the car, I can't warm it up. Does anyone have an idea of how much the cold engine will affect the results as opposed to a warm engine? They were pretty low, from 12% to 23% with the leakage going past the rings (air escaping from oil fill <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> er). Looks like a rebuild!
Thanks for any input,
Jeff

bryantch

First I must say that I am not a mechanic, nor do I play one on television. However, I recently talked to my local neighborhood mechanic about doing a leakdown on my 3.0 motor because someone was interested in purchasing it and wanted the numbers. The mechanic told me that leakdown tests are all but worthless if the motor is out of the car. The oil is no longer in the places in the motor that it would be immediately after shutting down warm, ie around the piston skirts/rings, valve seals, etc. and therefore it is impossible, in his opinion, to get a usable number. A compression test is possible albiet difficult with the motor out.

Good luck

Ian

pjc

Really needs to be a hot engine - typical results on a good engine are 5 to 10% Cold engine means the tolerances are greater which suggests your engine may be OK but it is difficult to tell. My 2.7 has done 104,000 miles and the readings were 6, 5, 8, 5, 5, 7% on cylinders 1 to 6 - so hey ho everything OK, if it ain't broke don't fix it!

pjc

racemechanic

Thanks for the replies. I think I'll throw the readings to the owner and let him decide on new rings, bearings, etc.

jeff

Schuey

this place helps

racemechanic

Yes, it does!
Just out of curiosity, I performed a leakdown test on my mower before mowing. It had a leakdown of 35%!! Then I mowed the yard and let it cool down just a bit. I then retested it and it only had a 15% leakdown then! Quite suprising.
Jeff

PCA Member 10yrs
1965 911 #300468!
1974 914 2.0
1987 944
and a bunch of junk!
Oh yea, the 1988 Celebrity Wagon for the snow!

ZCAT3

I like to see less than 10% leakdown in normal residential mowers -

racemechanic

Guess there comes another rebuild! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />
Jeff