quote:Originally posted by Captain Kirk:
5w-20 vs 30.........quote....
"5W-20 is used PURELY for gas milage for Ford. The Ford Explorer calls for 5w-20 yet the Mountaineer that uses the EXACT same motor, all parts are interchangable and has the same engine code, calls for 5w-30. My S10 uses 5w-30 or 10w-30 I've gone to amsoil15W-40 desiel oil with out a problem. The reason for doing so was for higher oil pressure during cold days."
AFAIK Ford doesn't recommend 5W20 in their 4.0L Explorer, it was one of the engines not back spec'd from 5W30 to 5W20 because of the oil pump the engine uses.
Ford as extensively tested 5W20 in desert heat towing, then there are several fleets across the USA using 5W20 with great results. This topic has been beaten to death all over the internet. This is turning into the classic which is better Ford or Chevy debates.
5W20 has been in use for several years now and many Ford products have logged over 250,000-300,000 miles without issue.
I would use it in an application that calls for it, having said that if my engine calls for 5W30 I would not use 5W20.