Motor is straining and belt is squealing and there is oil!

by Michael
(Columbus OH)

So I work at a public shop and our compressor is probably on its last leg. When it starts a cycle it seems to struggle to get up to running speed. It usually squeals like crazy while running, sometimes it phases in and out of squealing. I am not sure if the belt has been changed or if something needs to be tightened. An automatic drain has also been added to the tank due to our oil problem. I believe there is a leak in the motor somewhere. Is there a gasket or a more common issue that would cause this?

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Bill says...

Michael, it always helps to have some idea of what type of air compressor you are asking about.

a typical shop compressor is a reciprocating, 5 HP on a 60 gallon horizontal or vertical tank. Am I close?

Is it oil lubricated? If so, and you say there is no oil in it, then that may be the cause of your problems. Why not add oil?

If you aren't adding oil as the oil won't stay in the sump, but ends up in the tank along with the compressed air, that suggests a major piston seal or ring problem to me.

By the way, draining the tank will remove the oil and water mix, but it won't get all that compressor oil out of the air, and if enough of it gets to your tools, it may attack any Buna N or rubber seals in them.

Cheers,

Bill