Some Recommendations for jeep 4.0

[unclethumbtack]

I have been poking around this sight doing some research. I have two 4.0 jeeps.

1. 2000 Cherokee-96000 miles currently running 10w30 maxlife synthetic blend. Microguard filter. I was running conventional valvoline or castrol gtx before. So far I really like the maxlife. But I have read that these do better with a 40 weight oil, just wondering if I should go to a 10w40 next time round. I ordered a UOA from blackstone and will be doing an analysis I will post on here after it is back.


2. 1996 cherokee- 149,000 miles trail only rig, currently has ST 10w30 with a microguard filter, slight lifter noise. I acquired this jeep only 6 months ago, so I am not sure about the proper care of it before I took ownership. I am wanting to run a solid detergent oil to clean up whatever is built up over the years, I am wrestling between going with maxlife in this one too since it seems to get high marks and I have personal experience with it or go with the tropartic blend because it is reasonably price, or just stick with old dead dino's. I would like to get rid of the lifter noise if possible.

I know this is a lot to process but I would rather get others input than just shooting in the dark.

 

[MGregoir]

10W-30 HDEO. Thick end of a 30 weight, SJ/SL rated, loads of detergent. Good enough in colder temperatures. Oh, and cheap. Real, real cheap.

 

[bmwtechguy]

Several ways to try to get rid of lifter noise, but my first choice would be auto-rx. Check it out at their website or over on the oil additives forum here. You will find that some oils will do some light cleaning, but for the most part, oils are just good at lubrication. If you want to do some serious cleaning, Auto-rx is the ticket. I have also used Amsoil engine flush for a quick cleanup, and Schaeffers Neutra to do some serious engine cleaning over a 500-1000 mile run. I would have to say that the best results were obtained with the auto-rx stuff. Use it with the Super tech oil or trop-arctic, then when done with the cleaning, use Maxlife 10W-30 or 10W-40, depending on what works best in your particular 4.0

 

[MarkC]

My 96 has had only 10w30, either Castrol, Havoline, or Chevron, and it's thriving. Very good UOA's and no issues.
I think these will run on Wesson oil if they have too.
Just want to make sure you keep fuel dilution under control. Keep the air filter changed out no longer than 10k miles, keep the plugs and wires in good shape. Make sure the thermostat is the right one--195F, and that it's working properly.

 

[mpersell]

I've run my 2001 on 10w-30 Amsoil for its entire life. Keep in mind its a straight 6 and you'll never completely quiet it down.

 

[dave1251]

I use Pennzoil Long Life 15W-40 in my sister-in-laws 95 4.0 Cherokee. But since you live MO you may want to give shell rotella syn or M-1 Delvac 5W-40 a try.

 

[Brett Miller]

Jeep 4.0's will run for forever on good, old 10W-30.

 

[My442]

My son has a 1994 Grand Cherokee with 170,000 miles.

I use Exxon 10w-30 and whatever filter is on sale.

It still has over 50 PSI of oil pressure at cruise.

 

[Greaser]

Go to the UOA's section and search for Jeep 4.0L engine...have fun reading!

 

[unclethumbtack]

Well I went to store tonight I picked up 7 quarts of 15w40 rotella t, for my trail rig. I figure I will run it in the warmer months and go with a lighter weight when it gets back to the winter months. I am also going with the bigger filter (FL-1A) so I can run an extra 1/2 a quart.

 

[Challenger71]

Uncle 'T', I am using Royal Purple 5w=30 and I absolutely love it as does the 4.0 after testing with numerous oils and viscosities (all synthetics). While the engine is running, with the exception of blipping the throttle on occassion, I in fact do not hear any audible engine noise. I actually just hear the road/tire noise over the engine througout most of the useable rpm band. If RP can fit in your budget and you can get it locally then give it a try for an oil change cycle or two and take note of any perceived engine noise reduction.

 

[99]

HDEO is the only oil I'd ever use in a Jeep 4.0/2.5 simply for the fact these engines use a flat tappet cam/lifters. These parts need the extra ZDDP HDEOs have to stay alive in the long run.

I use Rotella 10W30 in my 97 4.0 and in the summer I use Mobil Delvac 1300 15W40 in it.

 

[Greaser]

HDEO is what I
ve been using in my Jeeps for years.I have the UOA's to show my Fe is very low so my valve train wear is great with the HDEO's.