air leaking out the oil filler cap

air is leaking out of the oil filler cap


______________________
Bill says....

The oil filler cap is vented to allow air exchange between atmosphere and sump, as conditions in the oil sump change.

There is not supposed to be air leaking out continuously.

Is it constant, is it happening when the compressor is running, stopped, or both?

If it is happening while the compressor is running, it suggests some leaking in the piston seal. That being the case, you would be getting quite a bit of oil into the tank along with the air.

Give me a bit more info as a comment here, please.

Cheers,

Bill


Comments for air leaking out the oil filler cap

Click here to add your own comments

Sep 21, 2015
Air leaking from oil fill cap
by: Anonymous

it seems like air only leaks out after it shuts off but might be during too. leaks air through oil fill tube and will drain the tank completely down. when it starts to kick back on it just hums, have to let it cool down then it will pump up fine then start leaking again.

Jun 11, 2014
oil filler vent plug
by: Anonymous

what is wrong when oil shoots out of the oil filler cap, a big steam of oil shoots about 3 feet
____________
Same as answer on similar question, and, if the oil sump is really overfilled, and you have signficant piston blowby, then you'll get a lot of oil blowing out the vent cap.

Bill

Dec 03, 2011
compressor
by: Anonymous

just started letting air out of oil fill cap, only when system is running

__________________

If compressed air is coming out the oil filler cap, then I suspect blow by the piston seals.


Click here to add your own comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Kobalt Air Compressor Issues.

how to put oil in air compressor

Can't find my manual. Can you tell me how and when I should add oil? It's a 5.5 gallon, 1 hp.

____________________
Bill says....

I expect you either have a sight glass or an oil dipstick to give you an indication of the oil fill level in your air compressor.

Ensure that the oil level in the sump is always as the "full" level, but don't overfill it.

Essentially, since all reciprocating air compressors consume oil, watch the fill level, and don't let it get below the "add" spot. And, it is normal to change the compressor oil every 200 hours or once a year.

If you need specific details, please add a new post, and include closeup photos of all side of your air compressor pump.

Cheers,

Bill


Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Kobalt Air Compressor Issues.

Oil leak 60 gallon compressor?

by Eric Fowler
(Ocean Springs, MS USA)

Kobalt 60 gallon air compressor (Photo:www.lowes.com)

Kobalt 60 gallon air compressor (Photo:www.lowes.com)

I have to fill with oil every time I use it. it leaks oil everywhere it can on the pump, even into the tank.

If I fill with oil, use the compressor, and empty the tank it will leak all the oil within couple of days.
___________________
Eric, a couple of things come to mind.

After you have cleaning off the pump housing and oil sump housing, can you see where the oil is exiting the sump? If not, that might let out a pump sump seal.

What I suspect, from your post, is that you have worn piston seals and you are getting a lot of oil bypassing the piston/cylinder seals, getting into the cylinder compression area, and that oil is blowing down into the tank while the compressor is running.

At the same time, you are apparently getting a lot of compressed air wicking by the seals into the sump. If the sump is full, it is possible that this air is pressurizing the sump a bit, and forcing oil up the fill tube, out, and onto your compressor.

You need to identify if the oil is coming out via a worn seal on the pump sump, or is it coming out of the oil fill tube?

The first will mean a gasket replacement. The second will likely mean a pump tear down, piston seal replacement, and while you are in there, I suggest a valve and gasket replacement too.

Cheers,

Bill

Click here to post comments

Add your own question or comment. It's easy to do. How? Simply click here to return to Kobalt Air Compressor Issues.