Water In Compressor Pump
 

About a month ago I noticed the oil in the sight glass of my compressor had the water in oil chocolate milk color. I changed the oil but in less than a month the chocolate milk is back. I removed the sight glass and can see that about all the oil is not draining out of the bottom of the crankcase. What can I use to flush the crankcase and is there anything do to prevent the condensation? The compressor is an Eaton 80 Gallon 7.5 HP.

I would do a mix of kerosene and 30W motor oil.. fill it up a couple times with that mix and drain it out, but then just flush it with more 30w until your comfortable that the kero is gone

Only thing I know of to control moisture in an air tank is drain the air daily.
You might find a pop off valve similar to what is on a compressor on a semi truck. Not only does it control the air pressure in the tanks because the compressor always runs as the engine does, but it blows moisture out in the process. I'm no expert on this subject but if I had your problem I think that is the first thing I would look into. I do know that all air compressed from the atmosphere has water in it which separate's when compressed and will find it's way to the lowest point in a system. I felt the need to reply as no one else has yet. Hang in there and maybe someone else with your problem will help out. Good luck. :D

if i read his post right, the water is in the compressor motors' oil, not the tank.

i would say just change it again. maybee twice.

Since you are getting moisture from condensation in your compressor crankcase the piston rings have to be worn to let the moisture get past them . The water should all be in the tank. And to comment on sqzbox post . Having been a heavy equipment mechanic for over 25 years I can tell you that how the system works is that the air governor contols the air pressure . When the air pressure reaches the adjusted setting air is sent to the air compressor unloader valve which then holds the intake valves on the compressor open and also sends air to the air dryer dump valve which discharges all the water from the bottom of the air dryer . A check valve on the output of the air dryer keeps the air in the air tank. When air pressure from the airtank to the air governor drops to the kick on pressure, the governor closes and discharges the air pressure to the unloader valve and air dryer dump and the compressor starts making pressure again. Hey, how about we put an air drier from a semi-tractor on our air systems ? It would work, but they are expensive. If I was still in the body shop business I would do it though .

We have a few semi truck bone yards around here whats inside the semi air dryer????

It certainly could be excessive blow-by which would not be good but another likely cause is simply the crankcase ventilation clogged. Are you finding an oily residue on the outside of the crankcase anywhere? A compressor pump crankcase needs to be ventilated just like a gas engine and if completely clogged, or nearly so, will start blowing oil out the crankcase in various areas. However if only partially clogged it may only blow little if any oil out but may pick up condensation from normal blow-by (even a new pump does not have a 100% seal on the rings) which will result in water in the oil, how old is this pump?

There is a cannister inside of the dryer that has dessicant and a filter to catch debris . Air comes in the bottom and out the top. Best feature is that it blows out the water at each cycle of the compressor. It could be plumbed in parallel with the moisture ejector on the bottom of your air tank. You do have one of those, I assume. The dessicant and filter can be bought in a kit to be replaced periodically as needed . Very easily serviced and seldom needs done unless you have a lot of oil pumping out of your compressor which plugs up the dessicant . Also a hose can be attached to the air dump valve to direct it wherever you want . If I wasn't retired, I'd get one from one of our out of service pieces of equipment for myself. Wish I would have thought of it a year and a half ago. Hindsight is always 20/20 . Hope this helps ...Allan

Thanks for the replies. I should add the compressor is three years old and in and in my garage that is unheated most of the time. I am going to call Eaton today. I the crankcase doesn't appear to be vented. I'll let you know what they say.

Here's the link to the Midland air dryer commonly used . I just found one on ebay for $259.99 . Like I said, they are expensive . But I seem to remember the service kit being about $35.oo. BTW , the heater on them is only to keep the discharge port from icing . Not a problem in a garage.


http://www.myvirtualpaper.com/doc/ca...91001/480.html

That price is about the same as a body shop decisent filter....For the life of me I cant figure out why they want so much for a canister that holds the little decisent balls...the service kits(for the body shop filters) contain more decisent balls thats about it..That water blow off is a neat little feature I'll check out a bone yard and see what they have ,That is a good idea...

I bought my compressor new in '83 but I only ran the bodyshop for two years until I moved due to a depressed economy . The point is my compressor crankcase is not vented either. It is a four cylinder single stage 17 cfm @ 100 psi. Never had a water problem in the crankcase, but have had the pump literally smoking hot when I've been doing sandblasting. I think I may have taken the temper out of the rings . Time for a rebuild .

One thing nice about the Midland is you don't have to buy the whole inside cannister if you don't need it . The kit has a sealed bag with the dessicant and the filter and a new check ball and all the o-rings needed to service the cannister . Allan

Your crankcase is surely vented, all compressor pumps are vented otherwise very high pressure would build up inside the crankcase. Different makers use different methods but rest assured it will be vented in one fashion or another.

I called Eaton. They recommend cleaning out the sludge with mineral spirits and using heat tape to warm up the crankcase. They also told me where to look for the vent.