Rev-x that i was using before was a monograde (not sure if it is the term) SAE-30. The engine never gave us problems and i never thought may sludge build-up, pero nung pumutok yung pressurized hose dun sa alternator running at high speed, it was knocking everywhere. After 18 years, pagbukas ng engine for overhauling, dun daming sludge sa crankcase and dun sa camshaft areas.

I was thinking of going synthetic pairing it with a baldwin filter. So ok lng yung 5w-40?