I've recently acquired a second hand oil-type cast iron belt driven
compressor. Is it normal for there to be some oil in the water
drained from the tank? Also, the oil site glass has no markings on
it--should the oil level be half-way up, all the way up, or what?
yes, it is common for piston-type compressors to pass a little oil. I
believe the oil should be to the bottom of the sight glass but check
your owner's manual to be sure. If you don't have one I bet you could
find a .pdf online. I'd change the oil anyway, it requires the same
sort of maintenance as your car would (as it is a very similar mechanism.)
replace "fly" with "com" to reply.
Some oil in the air is normal. Worn piston rings, wrong or too much oil in
the crankcase, or oil needing changed can increase the amount. Don't worry
about it unless you have trouble keeping the crankcase level up.
The correct level for most sight glasses is half-way. A straight 30W
non-detergent oil is usually satisfactory if you can not find the
Most compressors will pass some oil. If there is a lot, it means the
compressor is wearing out. Most air systems have some sort of filtering
system on them. Commercial and industrial systems can have rather elaborate
dryers, oil separators, etc. If you plan to spray paint, look into a
filtering system. Keep the tank drained as well.
If you keep the oil level visible in the sight glass you are good to go.
Don't overfill it either.
Some of the old cast iron compressors just keep on running for years. They
are quiet compared to most of the oilless models too.
OK, as you mention for spraying paint, this oil needs to be filtered
out. What about for air tools? Is the compressor oil comparable to
the air tool oil, so its presence in the air stream is a benefit?
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.