Another compressor problem

[Scott Donley]

I have an oil lubed compressor. Last week I started getting a fine mist of oil out of the unloader valve when it shuts down. I'm thinking rings maybe although it has no problem reaching pressure Also considered a plugged air filter . Makes no odd noise and oil level has not gone down, also no oil out of the air outlet. Any other Ideas ? Thanks

[Bruce Wrenn]

When was the last oil change? Check breather port for crank case isn't stopped up. It's often a little hole on crankshaft end of case, that looks like an oil cup.

[Scott Donley]

Thanks for the Idea Bruce. I will check it out in the morning. I did not even know it had a breather port .

[Scott Donley]

Well, no go on the breather port, could not find one. I am at a loss :( Anyone else ?

[Tim Howell]

There is a breather somewhere for the crankcase. Your saw dust probly has it clogged up.

[Scott Donley]

There is a breather somewhere for the crankcase. Your saw dust probly has it clogged up.Heck if I can find it :confused: I looked again after your post, flashlight, on my knees, kind of looking. I am about t give up and use it till it dies. Real shame is I just replace the drain valve with a Ball Cock last week, at least it no longer leaks air :o

[Ronald Blue]

What brand/size is it? Maybe more specific information will help.

[Scott Donley]

It is here (http://www.searspartsdirect.com/partsdirect/part-model/Craftsman-Parts/Air-compressor-Parts/Model-919195413/0247/0703000/50036493/00002?blt=06&prst=0&shdMod=919195413). A wild idea, what could I break if I drained the oil then ran about 80 pounds of compressed air through the oil filler hole. Should blow out any plugged breather, but what else ?

[Ronald Blue]

Possibly seals around crankshaft or the gaskets where crankcase joins together. I wouldn't pressurize the crankcase with pressure like that . It does show a vent filter in the parts break down but it isn't clear where it is. It is possible it draws any "vented" air back into the intake. There should be some type of vent. I agree the vent is the first place to check. All pistons leak a small amount past the rings. If it can't vent it could cause issues like you are having.

[Scott Donley]

Thanks, I am at a loss "cause I can't find it. Dang it all .

[Larry Whitlow]

Perhaps the breather is built into the crankcase oil plug? Shooting from the hip here.

[Scott Donley]

Nope, solid, no vent.

[Ronald Blue]

I am guessing it is going to be higher up on the crankcase. It looks like your fill plug is down low. For trouble shooting purposes possibly screw a pipe nipple in its place. I don't know if it will force anything out or not. Maybe 4 inches long? If it will run without making a mess see if it stops the problem. It make take several cycles to clear any residue out of the unloader if this is the culprit.

[Tim Howell]

Any lines connected to the air filter/ down pipe/ manifold all the way down to the valve intake? Can the down pipe between the filter and the head be removed? Any small lines connected to the head? It should be above the oil level but below the cylinder. Look for any strange shapes, clean the top of all cylinder to crankcase bolts - one might have a hole in it as the breather. Does the oil cap have a pin hole in it? Look under the cap and seal, some 2 cycles have a breather built into the fuel cap that way. Have you drained the tank lately to empty from full pressure? Is the discharge all water or is the a lot of oil in the discharge. Water only small amount of milky goo = rings ok. You do something wrong when you changed the ball valve. Water and oil will settle at the bottom of the tank, if it gets gummed it want drain and builds up in the tank. There anyway the drain valve you changed is wrong and tank pressure is forcing that water and oil in the bottom of the tank back up the drain line and then it blows out at shut down. You diddle with the drain line any? Did you leave the drain line open a little. Last ditch effert pump it up some, shut it down, make sure the pressure is relieved, the remove the oil fill cap, pressurize the crankcase - NO MORE THAN 10 LBS (your 80 number will blow the seals) and listen for air movement. After the above :) keep looking for a vent. The rings always let a little air past - even in the best conditions and that air MUST have a way to escape or you would build pressure until you blow all the seals - so there has to be a vent. I'm thinking you did something when you changed the ball cock valve - you had no problem before - a week later oil accumulates and starts to blow out the valve - what you say - beat your head against the door yet:).

[Larry Whitlow]

Nope, solid, no vent.

Sorry, I didn't mean the oil plug. I meant the cap where you add oil (the dipstick). That is where the breather on my compressor is.

[Rich Engelhardt]

A wild idea, what could I break if I drained the oil then ran about 80 pounds of compressed air through the oil filler hole
You can easily force more oil past the rings by doing that....

A little oil lowing past the rings and into the tank isn't anything unusual on an older compressor.
They sell a seperator you can plumb into your air line to remove it.
It also happens to a lot of portables if/when they get tipped over on their sides during transport.

Just keep a sharp eye on the oil level and watch for traces of oil/water mix (white gunk) when you drain the tank.

[Scott Donley]

Thanks for the ideas, I don't think installing the ball valve had anything to do with it as I was able to do it without having to turn it on it side just role it a few feet from the wall. It might have been going on for a while and just noticed it. I never change the line pressure and the unloader vents over the line psi gauge and noticed it when I adjusted the line pressure after changing the valve. No noticeable oil in the line or tank. I will give your ideas a try and if those don't work I will just have to live with it for now as a new compressor is not in my budget.

[Scott Donley]

Just to end this thread ( I hope ) and help any other that might have the problem. I took off the air filter and ran it through a few charges, Guess what, no more oil spray ! Guess I will order a new filter (3.29 + 9.00 shipping, that hurts ) > Thanks again for all the suggestions, I will remember them for the future.
PS: I did try the filter first but only through one charging cycle. :(