I haven't taken it apart to see exactly what the problem is, but its four years old. A full year out of warranty.
An hour or so ago it started making an awful racket. It sounded suspiciously like it threw a rod. I shut it down along with all the machines dependent on it.
Diagnostic step one. I looked at the oil sight glass, and it showed just below center. Figuring to see how much of its guts poured out I cut the top off a soda can to catch the oil and pulled the plug. Nothing came out.
As one of our members would say... Blink!!! Blink!!!
I looked at the sight glass again. The oil level looked the same. I stuck an air nozzle in the drain hole (turned off the compressor, but left the valve open) and blew thinking maybe it was plugged. A very little oil came out and several chunks of metal.
I check the sight glass almost every day when I start up the air for the shop. It never changed. I wonder how long it was running with virtually no oil.
Well, I'm off to buy a new pump for it. I can't run without air.