Originally Posted by Cab_Burge
Originally Posted by cudadoug
What is the difference that you have seen on a cold vs. warm leak down test?

Discuss.

Thanks!
15% cold after sitting for several days and then warmed up to hot scope
Let us know your results thumbs
Try rocking the crankshaft a tiny bit each way with pressure on it both cold an hot wrench No more than 2 to 4 degree from TDC, be careful while moving IT! twocents


I bar the engine around while doing a leak down.

Pull all the plugs, plug the tester into a hole which will likely push the piston down the bore if the valves are closed. Quickly rotate the engine around with a long bar until the valves close and pressure starts to increase. Continue to try to rotate the engine against the pressure until you can't go any further. Give it a few seconds to normalize and take a reading.

Consistent from hole to hole. Doesn't require any disassembly beyond pulling the plugs. Been doing it like this for years.

If the results don't match the theory, change the theory.