what oil are you using in your Jeep 4.0L

[cauto]

I have a GC 4.0L that has that annoying first start in the morning ticking noise (lifter I beleive). I would like to know any good oils that folks have been using that quite this beast a bit.
My jeep is driven 70% short trips around town. At the moment I'm using 10w-30 synthetic blend from Gulf ie Brad Penn but it's on the thin side. Any suggestions would be great.

 

[addyguy]

Lot of Jeep owners 'seem' to like/recommend a 5W40 for the 4.0, to cover all bases.....try something cheap, like RTS 5W-40, and see how it works, to start with.....

 

[MarkC]

I use Havoline 10W30 in my 96 and the UOA's are great. Very low Fe wear.

 

[retsaky]

Amsoil 10W30 in my '98 XJ 4.0. No problems so far and runs great @ 122,000 miles

 

[sw99]

I do 95% short trips so I always run 5w30. I have had zero problems and the Jeep is close to 90K.

 

[ThirdeYe]

I know a lot of people that use Quaker State 10W-30, and I've also seen some using Valvoline Synpower (unsure of the grade though). They've all gone plenty of miles with no problems, they're pretty robust motors.

 

[Gary Allan]

Use any weight you want. It doesn't care. Try a better filter to eliminate the lifter tick at start up. If it's lingering lifter noise until warm up, use Auto-Rx as directed. Keep the air filtration and injector cleanliness up to par and look forward to 200k or the equivalent in fuel expended.

The HDEO's are good. You don't have to worry about fuel economy. An economical jeep is an oxymoron.

 

[cauto]

sw99
I'm still confused about how Chrysler only says to use 5w-30 only up to 30f...thats crazy and 10w-30 for almost all temps. there are both 30w oil.

 

[cauto]

I'm actually in the rinse phase now. The air filter is only 3 months old and and used a few bottles of injector cleaner but it ticks away until warm up. But I have noticed that the tick does not last as long as it did before going into the ARX rinse phase.
I also used to application of Chrysler combustion chamber cleaner before chnaging the oil for the ARX rinse phase. you have to love watching the large cloud of smoke when first starting up the jeep with comb. chamber clearner in there, its like a crop duster.

 

[brian]

My Jeep 4.0 has seen Mobil 1 10w-30, Delvac 5w-40, and GC 0w-30. I usually change the oil every 10-12Kmi. It has 165Kmi on it now. The valve cover has never even been off until this month. The mechanic wondered if it was the original engine with all those miles. It has exhaust valve seat and guide problems but the bottom end was in such good shape I'm having the head rebuilt.

-brian

 

[sw99]

My manual says I can use 5w30 up to 100*. I really don't mind continuing to use it in warmer temps either. I have run 5w30 in several 4.0's and had zero problems, many of which had over 100K.

 

[Johnny]

Originally Posted By: Gary Allan
You don't have to worry about fuel economy. An economical jeep is an oxymoron.


I know that's right.

 

[MGregoir]

The 10W-30 is based on that old 5W-30 oils would shear down to a 20 weight quite badly and quite quickly. 10W-30 is more stable than 5W-30, so the odds of that 10W-30 still being a 30 after 5,000 miles is much greater than a 5W-30.

Newer oils are more shear stable in the 5W-30 grades. The Jeep 4.0 seems to like thicker oil, so 5W-40 or 10W-40 might be viable options as well.

 

[Brett Miller]

Mine runs well on 10W-30 Pennzoil Yellow Bottle.

 

[cauto]

MGregoir I tend to agree with your post. I don't to what extent a 5w-30 would shear in the GC with 70-80% local short trip driving but it my concern when trying to pick a good grade of oil. I posted earlier that I wondered why Chrysler would only recommend 5w-30 up to 30F but I suspect back in 2003 and early 04 when the truck was built that grade was not as stable as it is today, only a few years later. I'm hoping to try a thinker 10w-30 like maxlife syn blend.

The 5w-40 seems like a possibility.

 

[widman]

I would be inclined to think that if it says 30F it is a misprint. Sort of like the manual I saw the other day that said "SEA" instead of SAE. It happens.

And actually, my 4.0 Grand Cherokee was very economical as long as it was cruising at 60 mph at 14,000 ft above sea level. No wind resistance.

 

[cauto]

interesting that you say that because my Chiltons car manual suggets using either 10w-30 and 5w-30 past 100*F. Maybe it is a misprint. ugh

 

[MatrixMulisha]

I had a 95 cherokee that had the same lifter noise at start up. Changed to rotella 5w40 and man...what a diff. Much quieter and the temperature gauge seemed to be running a bit cooler too (dont know if it was just a placebo effect or not). Good stuff. I would go with a 40wt.

 

[N5XL]

While thousands of Jeep 4.0L have racked up millions of miles with regular and synthetic PCMO's, I personally run 5w40 Delo 400 Synthetic in mine. The flat faced lifters and valve train will appreciate the CI-4 level of additives. The potential for the converter clogging in a 4.0 is a non-issue with most 4.0's anyway as they are hard on exhaust systems, typically rotting out long before a converter issue can surface.

FYI, Jeep 4.0's are notorious for lifter noise....

 

[Raceman]

4.0's are bullet proof as long as they have oil. I have 2 4L Jeeps and together they have run 190k (130 and 60)on Valvoline conventional 10-30. Zero oil consumption on either one. Any good quality 10-30 dino oil is fine.