There is water build up in the Speedaire oil block..

by Jay
(Hawaii)

I have a speedaire 5Z640A compressor and I keep getting water mixed in the oil in the oil block in the pump. I keep changing the oil and after a couple of months, I notice the same thing. What could be the problem?

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Bill answers...

Hi Jay, thanks for writing in.

Compressing air generates water. If you want to understand why, details are here.

That water generally builds up in the compressor tank. Which is why it's good practice to drain your compressor tank after every use.

The oil in your compressor is in an oil sump, and I believe yours is splash lubricated, which means that as the crank turns (driven by the electric motor shaft) and the piston moves up and down, oil splashes up onto the parts to keep them lubricated.

If a lot compressor oil was in your air tank, it usually means that the seals on the piston are badly worn, oil is wicking by the seals, and getting driven into the air tank by the compression stroke of the piston.

Is that the case in your compressor? If oil can move one way past the seals, water vapor can move the other way into the sump. That might be a cause.

To my knowledge there's no connection between the air tank on the compressor and the oil sump. I can't think of any other way water (condensing in the sump from water vapor) could get into your oil sump.

Anyone else have any ideas for Jay?

Cheers,

Bill