My 2007 Kobalt K7580v2 80 gal pump model B5900 compressor has a problem. It never reaches the 175 psi to cut off. When the pressure reaches 100 psi it begins a loud POP-POP_POP sound. The sound is coming from a screw-in device on the compressor. Replacing this device might resolve the problem, but I don't know what part to order. I'm attaching a photo of the device. I would appreciate any advice on how to make this compressor work again.

I'm logged into the forum, sir, but did not see any picture?  Could it possibly be a high pressure relief valve that is blowing off below it's designed pressure?

I tried to upload a photo of the compressor, but this site would not accept the photo. Today I found a parts breakdown of the B5900 and the part that is making the POP-POP-POP sound is called a Dipstick Breath Assembly. This unit does not have a dipstick. It has a sight glass.

Sounds like to me that sight glass has a bad seal, but you'd think oil would be blowing out also?

That is an interesting comment. There is a very slight oil leak from somewhere. The sight glass still shows about half full, but there is obvious oil on the platform beneath the B5900. I will look closely.

Close inspection of the sight glass shows oil seeping around the gasket. My modest tool kit doesn't include a 41mm socket to tighten the sight glass. I have ordered a socket.