Elistan

With 100k on both cars, we want to get an idea how healthy they are.
Later will be inspection of the valve retainers, but for now we want to make sure the vales and rings seal okay.

Also, while I certainly understand how each are done, do they tell you different things? I mean, will a leakdown ever come back okay but a compression test show an issue, and vice versa?

davidnyc

When I was purchasing my used '07 from a random used car lot, I just did the PPI at a Honda dealer and asked for a leak down (check valves) and compression (check pistons)... I believe I have that right.

Vanishing Point

Compression test determines the max pressure while cranking (engine moving) while the leak down determines how much cylinder pressure is lost and where, with a static engine.
Good cylinder leak down tests should be in the 5-8% range. The leak down enables the tester to audibly hear any air escaping and hopefully then determine the cause.

Gernby

If you can't find anyone to do it, I might consider buying a leak down tester myself. I just bought a new compression tester a few months ago. If you want to come by, we can check the compression.

Elistan

But what's the point of a compression test if a leak down already tells you if everything is sealing well?

Vanishing Point

The compression test measures how much pressure the engine can produce while cranking by individual cylinder, in contrast to the C.L.T. measures how much pressure is lost in the engine as a whole. Say past the rings, exhaust side or intake. At least that's how I differentiate the two.

davidnyc

Found the following on the web:

http://www.dietersmotorsports.com/Co...akdowntest.htm

>>>>>>

http://www.wcengineering.com/articles/leakdown.html

s2k manic

hi i mentioned that i was looking to get a valve spring tool in your other post you can rent a leakdown tester ti will tell you where the leakage is a compression tester will just tell you if your motor is loose leakdown just gives more info let me know if you need help i work on the cheap