Anyone ever run M1 0w40 in a 4.0 Jeep?

[53' Stude]

So with all this talk about how good M1 0w40 is; have any of you run this oil in a 4.0 engine? I am using QSGB 5w30 in my 97' 2dr Cherokee. Just curious is all and NO I have not thought of using 0w40 in mine

 

[zach1900]

You haven't thought of running it in yours? Lol

 

[53' Stude]

Nah, I havent

 

[derweed]

Never used Mobil 1 0-40 but I have some Castrol 0-40 I picked up for $5 per five quart jug during the Autozone end of year clearance that is going in my Jeep this week.

 

[bullwinkle]

I'm sure it would work-but it's extreme overkill, the 4.0 can run on just about any halfway decent PCMO or HDEO you put in it, from 0W30 to 20W50, & everything in between. If you search in the UOA section, some people have had high iron readings in a 4.0, not sure if the oil is just cleaning, or if something else is happening.

 

[53' Stude]

Thanks Bullwinkle and yeah I think the 0w40 would be a tad thick for even a 4.0 That's just me

 

[KCJeep]

On paper the M1 0w40 is a great match for the 4.0 IMO. In reality, the Jeep 4.0 has shown a consistent dislike for Mobil 1 in the past, and additionally the best UOA's have NOT been obtained with fancy full synthetics of any brand.

If you want a full syn for the 4.0 Rotella T6 is the way to go. Otherwise you'd be better off with something like PYB in my experience.

 

[Brian Barnhart]

My son is running it in his '96 Cherokee. I bought it new and ran 10W30 M1 for the first 12 years or so. Since then he's run mostly the 0W40 M1. Has over 250k on it now. Still runs pretty good but the rear main leaks very badly.