Air compressor overhaul or replace

10-4 on purge valve. If it's stuck open you wont build air pressure. If it is open, you can close it with a pliers. Check that first before replacing other part.

 

I had this same exact problem and it was leaking out the purge valve. Easy to check. Build up truck air to max then kill engine. Cover the purge with your hand for a minute. Then pull it off you will hear the air escaping. There should not be any air escaping.

 

If you have oil leaking from the compressor, you may only have a gasket that need to be replaced. That is a simple fix. I would check all bolts and hoses to make sure they are tight, first.

 

With that kind off mileage i wouldn't waiste my time and money and replace the whole compressor.
Don't forget that if it just a few dropps off oil gets into your airsystem,they will do damage to all your valves.

 

I once had to rebuild an air compressor on the side of the road. That was interesting.