Leakdown Test on a Cold Engine - Seller Says this is Useless?
10-06-2011, 10:14 AM
#1
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Leakdown Test on a Cold Engine - Seller Says this is Useless?
So I bought a motor off Sonshine Autoparts and had my shop do a leakdown test on this engine.
The results: 88% leakage on cylinders 1 and 2, 55% leak on cylinder 3, 20% leak on cylinder 4.
Obviously this is terrible so the shop advised me to send it back, which I did.
Ultimately, here was Sonshine Autoparts' reply after they received it back. I'm not sure what to make of it, can you guys comment?
The results: 88% leakage on cylinders 1 and 2, 55% leak on cylinder 3, 20% leak on cylinder 4.
Obviously this is terrible so the shop advised me to send it back, which I did.
Ultimately, here was Sonshine Autoparts' reply after they received it back. I'm not sure what to make of it, can you guys comment?
I won't go into a pissing match with your mechanics but after assisting in the diagnostics of this engine,right off the bat my guys questioned a leak down test on a cold engine ,they explained to me that engine cylinders are never perfectly round but oblong to compensate for heat expansion therefore you would never be able to get a properly sealed engine when its cold.
Feel free to contact me for further explanations
Thank you
Don Laniel
dlaniel@sonshineautoparts.com
Feel free to contact me for further explanations
Thank you
Don Laniel
dlaniel@sonshineautoparts.com
10-06-2011, 10:48 AM
#2
He is correct. If the engine was in fact cold, a leakdown test will not be accurate. The pistons expand as they heat so they will "fit" the cylinder better. This is why you don't want to rev high until the car is warmed up.
Those readings are terrible. So terrible that you would have noticed it driving. Actually I doubt it would even go anywhere with 88% on 2 cyls and 55% in another.
Those readings are terrible. So terrible that you would have noticed it driving. Actually I doubt it would even go anywhere with 88% on 2 cyls and 55% in another.
10-06-2011, 11:15 AM
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The motor was never installed, I asked the shop to test the motor to make sure it was ok before they put it in.
Should the leak be completely different between all the cylinders? I would expect more leak than usual but I would not have expected 88% in one and 20% in another, that's quite a difference.
Should the leak be completely different between all the cylinders? I would expect more leak than usual but I would not have expected 88% in one and 20% in another, that's quite a difference.
10-06-2011, 11:30 AM
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i dont think that it matters that the piston is at TDC. it matters that the valves are closed.
and yes, a cold leak down test isnt the greatest but an 88% leakage is not even close.
to me these numbers sound like either one of two things, a test that was performed with a valve half open or a reallllly bad motor. was a compression test performed?
and yes, a cold leak down test isnt the greatest but an 88% leakage is not even close.
to me these numbers sound like either one of two things, a test that was performed with a valve half open or a reallllly bad motor. was a compression test performed?
10-06-2011, 11:48 AM
#7
i dont think that it matters that the piston is at TDC. it matters that the valves are closed.
and yes, a cold leak down test isnt the greatest but an 88% leakage is not even close.
to me these numbers sound like either one of two things, a test that was performed with a valve half open or a reallllly bad motor. was a compression test performed?
and yes, a cold leak down test isnt the greatest but an 88% leakage is not even close.
to me these numbers sound like either one of two things, a test that was performed with a valve half open or a reallllly bad motor. was a compression test performed?
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10-06-2011, 11:59 AM
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10-07-2011, 02:40 PM
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It doesn't matter if it's at tdc or not. As long as the valves are closed like street ruler said. Or just loosen the rockers so they won't open the valves. Which would be easy on a motor on a stand.