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Flushing Compressor Crankcase

My IR T-30 compressor has the residue of 40 years in the bottom of the crankcase. It seems to be all liquid, but thick enough so that it doesn't flow very well, and even with the compressor blocked up so the sump is tipped toward the drain there's still a fair amount that won't come out.

Changing the oil several times would likely clear it all out, but there's enough water in the goo that it does make the new oil creamy pretty quickly. What about flushing with ATF or other light oil? I'm not talking about running the compressor this way - just pour in a quart, slosh with a long handled brush or something thru the filler plug, drain, repeat as required.

The advantage I see to using ATF is it's *much* cheaper and much less viscous at room temp than compressor oil. If it was a gearbox I'd flush with kerosene, but don't want to introduce anything that volatile/flammable into a compressor. Any thoughts on this?

Ned Simmons

Reply to
Ned Simmons
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I've used solvent on several units over the years. It's going to clean better than an oil IMHO. If you can get a brush into the case, then you could also get an extension tube attached to a blow gun to get nearly all of the solvent evacuated from the case (tilted with the drain port at a lower level with a rag around the port).

I've used stoddard-type solvents and a paint prep-clean solvent (wax and grease remover) for case flushing with no adverse effects. Any vapors will be forced out as the air is introuced. The solvents will clean and drain more effectively than oils.

If you don't have another source of compressed air, you could use something like one of those foot operated pumps for rafts, or other portable apparatii.

WB .............

Reply to
Wild Bill

Thanks, Bill. I like the idea of blowing the solwent out. Without that step I was little nervous about unintentionally making a diesel engine.

Since it seemed as though the gunk needed thinning rather than dissolving, I started with ATF, holding the solvents in reserve. After flushing about a pint thru and sloshing a bottle brush around I could see that the sump casting was nice and clean, so continued diluting and flushing the goo with about a pint of ATF at a time. Not having another source of air, for the last few cycles I rigged up an aspirator with a little vacuum pump and a peanut butter jar to suck out the little that couldn't make it to the drain. After about 4 flushes the ATF looks almost as good coming out as going in.

I'll refill with compressor oil and run for a short time then change it again and I think all will be well for another 43 years.

Ned Simmons

Reply to
Ned Simmons

After you refill the crankcase with oil, roll it around to get oil on the bearings and cylinders. This will prevent a dry start after the solvent bath.

Reply to
Andy Asberry

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