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Reply To: Compression leaks on compression check

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here Compression leaks on compression check Reply To: Compression leaks on compression check

#963914
Nightflyr *
Richard Kirshy
Participant

I think it would be wise to perform a leak down test on each cylinder
The results are pretty straight forward:
With both valves in the closed position (TDC) for each cylinder tested …
If it shows good on the gauge all is well
If it shows lower and its loosing air
There are basically 4 paths it will go.
If you hear air coming out the throttle body, you have a bent intake valve or damaged valve seat
If you hear air coming out the tail pipe, you have a bent exhaust valve or damaged valve seat
If you heat air coming out of the oil fill spigot on the valve cover, you have blow-by of the piston rings into the crank case.
If you see bubbles forming in the radiator with the cap off, you have a bad head gasket at best or a cracked head or engine block.
If you hear air escaping from between the head and block ( soapy water will help pin point the area) your looking at the same issue(s) as the one above.

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