Originally Posted by JjCoDeX75
The test was done with the cylinder set so both the exhaust and the inlet valves were closed. So as such, any escape would either have to be due to a poorly seated valve (unlikely as car runs reasonably well), or running past the piston.
That sounds right, however, the leak could be diagnosed as an exhaust valve leak by listening for air flowing out into ex. manifold, inlet valve leak by listening on the inlet side.
If no sound from either it's either HG or rings.
I *think* it's possible to know if it's HG by watching for bubbles or something like that in coolant, but I am not 100% sure.
The reason for doing a leak down instead of straight forward compression test is that it allows you to find where the leak is, rather than just state "compression" is low, which could have nothing to do with rings if you see what I mean.
By opening the inlets and somehow sealing the inlet manifold, I guess you'd know how much the guides are leaking.
I am only trying to use common sense here, I have never done this sort of thing before
