My 99 F350 v-10 owners manual calls for 5w-30 oil. The newer vehicles call for 5w-20. I don't imagine that they changed the engine any for the lighter oil, but I don't know.

Can I switch to 5w-20 and be OK?

 

Pete,

There is very little difference in the drivetrain design between the 99-04 2v v-10's. The only difference (upgrade) was mainly to the exhaust flow/intake system in early 02 to get more HP and torque out of the beast. The engine is basically the same, and 5w20 Motorcraft synthetic blend would be what I would suggest going to to make the swap. You will probably find your engine running a bit smoother with the change. You will be alright running 5w20 in your 99 2 valver....


-Casey

 

I switched to it in mine and actually bumped up the gas mileage a couple MPG!
I know it is contrary to what the manual says, but use it with cinfidence. I also highly recommend Motorcraft synth-blend and the Motorvraft filter(available at wally world) . Don't do ORANGE!

 

Thanks. I have been using Motorcraft oil and filter for a while now. Dropped ORANGE many years (20?) ago!