I was reading several of the threads here in the tool shed and reading one about an air compressor made remember when mine locked up. Maybe this little story will help someone down the road.
I bought this compressor several years ago for the tools that required air in my woodworking business. My employee came to work one morning and found the shop full of smoke, with the compressor motor running, and the compressor wasn't. We had let the oil run low and it had seized up. The smoke was from the belt getting burned to a crisp.
I took the compressor off, removed the bolts, and pulled the block up but didn't let the piston rings out. That gave me just enough room to work. It didn't have rod bearings; just aluminum, one piece rods on a steel crank. I heated the rods with a propane torch until I could turn the crank, then sprayed WD40 while turning it.
After turning it for about 5 minutes the WD40 had washed out all the loose aluminum particles and I started dripping ATF on it while turning. After 5 more minutes I switched to 50 WT trans oil. 5 more minutes and I switched to Lucas hub oil (thicker than regular gear oil). I dripped and turned for about 10 minutes to make sure that thick stuff had gotten in between the rod and crank. I wiped everything clean, put it back together and filled the crankcase with Lucas hub oil.
I suppose just about everyone would say you can't run oil that thick in there, but it has been running like that for a few years now and the crankcase doesn't leak anymore.