Quote:
Originally Posted by Gorman240
Leak Down test will be your best friend, make sure Cylinder is on TDC. Heres a list of what could be broken with their respective symptoms.
Exhaust Valve- Air coming out of Exhaust Pipe
Intake Valve- Air coming out of Throttle Body
Piston Rings-Air coming out of Oil Cap on Valve Cover
Head Gasket-Air coming out of Radiator
Find your Leak=Find Your Problem! GL
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BOOM! exactly. Make sure the engine is warmed up or your leak down numbers will be crazy. Its done on a percent system. Process goes as follows:
1. warm up engine
2. 27mm socket on crank pulley rotate cylinder in question to TDC (1342 firing order)
3. fire up your air compressor and let it pump up to 120psi
4. close/unscrew your leak down tester and screw it into spark plug hole of TDC cylinder
5. connect air to leak down gauge
6. slowly crank up the pressure with the knob to 100psi on the pressure gauge
7. the other gauge will read a number from 0 to 100psi, this is your leak down percent.
My S14 SR at ~60k leaks down about 97-99% depending on the cylinder. Anything 92% and above is runnable. If it gets below that or is like 50-75psi your motor needs attention.
Gorman240's synopsis is spot on. It may be easier to pull off a crank case return hose to hear that leak as the oil cap is a bit close to the leaky air chuck in the spark plug hole... just making it easier to hear the leak. The intake or exhaust will be obvious and should echo through the exhaust and build up pressure if you cap them with ductape or something similar.
Good luck!