Leak down on a cold engine

[jwakil]

I know that the procedure for a leak down test is to do it on a warm engine. However, I will have the engine partially out, and obviously not warm. Should there be a big difference in leak down results? Should I expect better or worse results when cold?

[Justin@Athens]

Worse when cold. But probably not by a huge margin. What you really want to look for, just as when hot, are large deviations between cylinders vs. the overall leakdown %. From what I have seen, less than 8% is great. 10-12% when cold might be a what I would consider acceptable. I am no expert in this matter though--interested to see what other have to say.

[manbridge 74]

Consider removing plug for each cyl AFTER it is at TDC so as not to get any carbon between exh valve and seat skewing numbers.

I like to do leakdown cold and comp test hot and compare numbers afterwards, noting any inconsistency in results.