I have a 1993 B250 5.2. Runs well after I bought a service manual and realized that my last mechanic wired the spark plugs wires in the wrong order. they were close though, in his defense. Now this guy has 120,000 miles and runs great (van - not mechanic) with new shocks and transmission - smooooooth. I would like to keep it that way. - - Until the next challenge which looks like exhaust system. So for a climate like Northern California - which is mild, what would be the best oil for this van?. I used 20W-50 and 10W-40 and i don't know which to stick with. I have no oil leaks - although I say that in disbelief. But there is 120,000 miles on a US built engine - which reminds me of the 8 cigarette butts I found on top of the fuel tank when I dropped it last year.

I ask you for some good advice.

 

Castrol 10w30 if you dont want to go synthetic. I actually run 10w40 or 15w40 Amsoil. My rig has 160,000+ on it though. 20w50 is mainly a racing weight oil.

 

I run 5W-30 synthetic without any problems.