quote:Thats a 10k mile oil in the right engines/driving conditions
Originally posted by TallPaul:quote:Citgo Ultralife (high mileage) 10w30 lists a 100C viscosity of 12 cSt.
Originally posted by MarkC: Maybe I'll just try one of the heavier 10W30's.
quote:The mid 90s Jeep oil pressure spec for the 4.0 is 37 psi @ 1600 rpm. Don't know what the '88 spec is, but perhaps you were fine with a 10w30.
Originally posted by MNgopher: The 5w40 stays right at 60 psi, even during an 8 hour run in 95 degree weather.