what to run in the i6 4.0

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I bought a 98 jeep Cherokee in pretty good shape has 225,000 miles in It but doesn't run like that at all. What have you jeep guys had success running in them? Conventional recommendations only please with the miles on it I am not interested in synthetics. Thanks everyone.
 
A High Mileage 10W-40 should satisfy your engine nicely, with a 5W-30 HM as an option in the winter. SuperTech HM for a well-worn 18 year old engine is plenty capable.
 
A lot of the jeep guys on the forums like to use Rotella. You may want to get on one of those forums and talk to them.
 
I've run lots of Castrol GTX HM in my grandfather's 96' and my brother has too in his 213k mile 91'.

I'd flip a coin for either Pennzoil HM, GTX HM, or MaxLife HM.

I've been unable to tell the difference when running 10w30 GTX HM to 10w40 MaxLife in either one.

I'd pick a 5w30 in your climate
 
I use hdeo. It will run on milk and cookies (for a filter) if you let it. Can not go wrong with this engine..
 
I have a 2000 4.0 JGC and the best results (in FL) have been with 10W30 Valvoline MaxLife Blend and Castrol GTX High Mileage (a blend). I have tried many other brands, but these 2 have had no startup rattle and best highway mileage.

I tried a 10W40, but it was too thick, and affected mileage. The 10W30 has been best. This engine now has 140M on it. Started with M1 for about 4 years, then PP for a couple years. After 100M it started leaking a little, so I went to HM oils. They have reduced the drips to just a couple per night. Great engine, but I have a good mechanic who knows them well...

VW
 
I've ran a lot of different oils in the old 4.0...

Favorite so far has been Pennzoil Platinum and Yellow Bottle 5W-30 grade. Low wear numbers with both and they don't drop your fuel economy like the heavier XW-40 oils do.
 
Ive ran alot more differnet oils in Jeep 4.0s(have 5 Cherokees with the 4.0 right now), Moms 2001 XJ has 4.0 i take care of as does Girlfriends 2003 WJ, that currently burns the Castrol EDGE 10w-30 its filled with. I can say that if Your 4.0 is in good mechanical shape, a 10w-30 is ideal, and what Crysler recommended from the factory, not 5w-30. Not that 5w-30 is bad for the 4.0, in sub 20 degree temps, i think the 4.0 prefers a 5w-30, but above freezing, I use 10w-30. Plain old, current PYB (conventional Pennzoil) in a 10w-30 weight is hard to beat, maby one of the best oils for the Jeep 4.0(my 87 XJs 298,421 mile 1st year 4.0 was run on PYB until i bought it at 269,??? miles, and still very strong and smooth, no ticks, oil burning, just a little rear main seepage) its just so plain jane for me.
 
I've used Chevron Supreme, PYB, Rotella T5 and now Defy and honestly couldn't tell much difference at all between them. I will say that my last change on Defy has quieted it down just a bit. Not that it was very loud but it is noticeably quieter.
 
I had good success with Max Life 10w-30 in the Jeep my daughter used to own. Good UOA's considering it had over 150k on it. I tried Rotella Syn Blend 10w-30 once and it burned that stuff like crazy.
 
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I had a '96 ZJ with the 4.0L and ~210k miles on the odometer, lifted on 31s, I ran SuperTech HM 10W40, sold it about 18 months ago to a guy at work he's still driving it daily.

I am pretty sure I could have used Wesson or store brand Canola oil. I wouldn't use EVOO, too expensive and smoke temp is too low.
 
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Would I see any difference running a 5w30 vs a 10w30. I was kinda considering vwb or maybe mobil super how do jeeps like those choices?
 
For cold weather I would prefer the 5w30, but only run it 2500-3000 miles. The 4.0 can shear it down to a 20 weight in that time.
 
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