AIR IS BUILDING UP IN THE CRANK CASE

I DO NOT KNOW IF, THERE IS A VALVE LEAKING THROUGH, CAUSING THIS CRANK CASE AIR PRESSURE TO BUILD UP AND THEN IT LEAKS OFF, AND THE COMPRESSOR KICKS ON, BECAUSE IT LEAKS PRESSURE OFF, IT IS A 5 HORSE POWER 2 STAGE OLDER AIR CPOMPRESSOR THAT I CANNOT FIND ANY INFORMATION BECAUSE THEY SAY THEY DO NOT MAKE THIS PARTICULAR AIR COMPRESSOR ANY MORE, IT IS A 1986 INGERSOL RAND, THE COMPANY HAS NO PARTS NOR INFORMATION ON IT ANY MORE , ANY INFORMATION WILL BE APPRECIAATED. THANK YOU

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Bill says...

Air should not build up in the crankcase. If air is wicking by the piston seals and getting into the oil sump, that oil sump should be vented, so that pressure can't build up.

It is common for the oil fill port to be vented. If that vent gets block, then pressure could build up in the sump.

If there is lots of air, this could indicate that you have excessive wear of the piston seals, and this, too, would result in a longer fill time to cut out pressure.

Cheers,

Bill