When I bought my truck it had 3000 miles on it. The guy that had it before me had already changed the oil four times in it. I changed it at 6000 and put in Motorcraft 5w20, when I cranked it it made a knocking noise (piston slap/rough bearing?). So I put in AMSOIL 0w30 but it did'nt help much. Is 0w30 to heavy for this motor? Do I need to go back to the Motorcraft or just stick with AMSOIL? Thanks!

 

i have seen 5W-30 recommended many times on the boards, and one of the guys that recommends it (Superfords) is a ford technician, so he knows what he's talkin about.