discomikey, I put normal cv lithium grease,NLGI2, for temperatures from -30 to +130 degree. The compressor takes very hot, you cant touch it too much time. Now I have dismounted the compresor, and find grease over the head from 1 piston, and some balls from some piston rods moves very hard...I try again with another compressor when I have time, and I think I gonna put compressor oil into...sorry again for my poor english, Im spanish...