A leak down test puts air into the cylinder then the guage shows if there is a pressure loss and if so, how much pressure is lost during a set time. All cylinders are going to leak some though. You can sometimes hear the air escaping through various parts though. Through the intake then probably an intake valve and same with the exhaust. If you can hear air coming through the oil filler cap then it is most likely worn out rings, if you get bubbling in the radiator, well that pretty much shows a gasket problem and if you can hear air coming out the sparkplug hole next to the pressurized one then it is again the gasket.
I'm sure more out there have more info, but probably a shop that you trust and would let you see what's going on would be best as the guages might be expensive.
Russ
|