how can you tell if its the rings, valve seals, headgasket ect from a leakdown tester? thanks

 

Based on where you hear the air escaping from.

Rings = Oil Dipstick
Valves, Seals = Valve Cover, Intake & Exhaust
Headgasket = Oil Dipstick, Bubbles in Radiator

Any questions?

 

ohh, so you just listen for the air leaking? then whats the gauges for? thanks

 

Yes,

One gauge tells you you have supplied 100psi to the source.
The other gauge tells you how much air is escaping.

So if the second gauge reads 85psi you know you have 15% leakage somewhere, now you listen for air.