5W-30 - Try Amsoil - in my 1995 Buick Regal my MPG went from 20 to 23 just by changing the oil - Amsoil spec'd I could use 0w30 - stuff is like olive oil - very runny. Used it on every vehicle ever since ( did that in y2k -thats year 2000 for all you youngin's ). Combine that with Amsoils 35k oil changes, 12k filter changes you'll have more time with the welder.
