want to switch over to a synthetic oil jeep has 198k 4.0 five speed was wondering what were some of the best to run and best for the engine

 

with that much mileage on the motor, i wouldnt. anyway, i run rotella T6 5w-40 and love it. switched at just under 90k miles.

 

I run Rotella T5 synthetic blend, 10W-30, on mine. It has 219,000 miles on it and I switched over at around 193,000. Haven't had any issues with it.

That said, I am also a bit paranoid about switching to full synthetic with so many miles on it, which is why I compromised (in my brain, anyway) with the blend.

 

I run motorcraft 10w30 oil and 75-140 in my diffs all synthetic blend I'm happy with it.

 

I run castrol edge full synthetic 10w30 with 192k and love it

 

I heard 4.0s don't respond well to synthetic.

 

School me here if im wrong but isnt rotella for diesel engines? Ive always heard everyone saying rotella, rotella, get rotella! But I always pass it up on the shelf for mobil1 full syn 10w30 and a mopar filter.

Is rotella superior? Im at 92k right now.

 

Rotella is a 15W-40 oil. It will work fine in an older 4.0 or motor. Using it is not much different than using 20W-50 except the Rotella has detergents in it that will help keep the engine clean.

 

Rotella has zinc, which flat tappet cams like the 4.0l need keep from wiping out lobes. The EPA took the zinc out of the oil intended for gas motors to prevent catalytic convertors from plugging up. They figured most cars on the road have the newer hyd roller cams to justify the reduction. Search ZDDP and you'll find tons of info.

 

Wow I never thought you can put oil for a diesel in a gas motor. Ive ran Rottela in my semi for about 5 years before i went back to being a company driver.

 

i switched to full synthetic, now when my engine is warmed up and at idle oil pressure drops to almost nothing, i was thinking it could be the sending unit giving a bad reading but im not 100% sure of anything, anyone have any suggestions?

 

They figured wrong! Im running a modded 71 IH tractor motor.
20W-50 is what I normally use but sometimes a jug of Rotella is cheaper. (14bucks) and I use it instead.

 

I had an old zj with similar miles that I decided to put full synthetic in. Long story short it leaked from every possible gasket. I will never put synthetic in a high mileage vehicle again. I stick to regular good ole earl now.

Hey say synthetic flows better. So that could be your oil pressure issue but im not sure on that.

 

I put synthetic in my jeep last oil change (125k) and my oil pressure acted funny for a couple weeks at first, would drop to nothing sometimes had me nervous. Till I did a little research and waited, sure enough about 1k miles into the oil change everything is running back to normal.

 

Rotella is a brand. It comes in 15-40 Dino, 10-30 blend, and 5-40 full syn.