95 Jeep Grand Cherokee

Gary Allan · Jun 28, 2004

The 4.0 appears to like a heavier oil in general. My UOAs found substantially reduced wear with a 5w-40 over xw-30..but I'm into extended drains and am commited to synthetics. One member appeared to have good results with Amsoil 5w-30

Do a search in UOA using 4.0 or jeep as the term. I'd like to get back to a xw-30 ..but I've got some other oils in stock that I'd like to check out before I do this.

JonS · Jun 28, 2004

I have a 95 GC with the 4.0 and it seems to like the 5w-30 best. With a heavy 10w-30 (like castrol GTX) my pressures would be at 70-80 psi at startup and driving cold. too much for me. I did put in a new pressure sendor, so the pressures are correct. 15w-40 would be to thick.

KW · Jun 29, 2004

I've run Rotella 15W40, Mobil 1 5W30, Mobil 1 5W30/15W50 mix, Mobil 1 0W40, and Amsoil 5W30. Currently I am using Amsoil 10W30. In my 4.0 everything worked well but the M1 5W30 which seemed to be to thin for the motor. It made the motor very rattley and rough feeling.

If you go with your favorite brand (Mobil 1) I'd pick the new 5W40 that is out now and run it for 5 or 6K and see hoe it does.

Brian Barnhart · Jun 29, 2004

The '95 could be different, but in the case of my '96 Cherokee the owners manual recommends 5W30 for 60F and below, and 10W30 for 0F and above for the 4.0L. Mine has had 10W30 M1 for most of it's life (92K miles). Right now it's in the middle of an AutoRX treatment and has Havoline 10W30 dino in the pan. The engine seems a little quieter with the 10W30 Havoline than with the 10W30 M1.

SteveD2 · Jun 29, 2004

quote:

Originally posted by Brian Barnhart:
The '95 could be different, but in the case of my '96 Cherokee the owners manual recommends 5W30 for 60F and below, and 10W30 for 0F and above for the 4.0L. Mine has had 10W30 M1 for most of it's life (92K miles). Right now it's in the middle of an AutoRX treatment and has Havoline 10W30 dino in the pan. The engine seems a little quieter with the 10W30 Havoline than with the 10W30 M1.

Newer ones recommend only 30 weight, because as allways, the EPA has to stick their nose where it doesn't belong. The 4.0 is a big old hunk of iron designed in the 60s. Basically the only changes since then is fuel injection. Thicker oils are best. The manual for my old '90 said to use 5w30, 10w30, or 10w40. Nothing in the engine has changed since then. Only the EPA requirements have changed. Either way, this engine will last at least 300,000 miles no matter what weight you use, as long as you keep it relatively clean.

guitarrocks · Jun 29, 2004

thanks, just talked to owner in Montana and they said Castrol GTX 10w-30 was used. Hope the engine lasts.

guitarrocks · Jun 29, 2004

Just bought a well used one with 144,000 miles. I have no experience with this line of product (always been in the small foreign car with Mobil1). From the previous owner they changed the dino oil every 3000 miles but gave no rec on the oil type/vis. What would be the best oil? I would guess staying with dino would also be a recommendation? thanks, guitar

Bror Jace · Jun 30, 2004

"... just talked to owner in Montana and they said Castrol GTX 10W30 was used."

Don't let that make you think you need to stick with that oil permanently (brand and/or weight). The old wives tale which says that once you start using a particular oil you should stick with it is just that ... an old wives tale.

--- Bror Jace

Greaser · Jun 30, 2004

Yep the 4.0L Jeep engine is a low revving,low compression "tractor engine" from the old days that needs minimal care to live.May-be a little engine flush from the recommended brand around here...I think it's Auto RX....then a good quality dino or synthetic oil/ filter combo afterwards.Personally I use Napa Gold/Wix oil filters in the Ford oversize (#15151) and Delvac 1 5W-40 in both my Jeeps 4.0's.

MNgopher · Jul 1, 2004

As others have pointed out, the origins of this motor go to well before Chrysler slapped the generic 10w30/5w30 recommendation on this motor.

On my '88 Cherokee, the owners manual (still all AMC, not Chrysler at this point) allows the use of anything from 5w20 to 20w50 depending on outside temps in the 4.0l.

Honestly though, a 10w30 regularly changed will last a long, long time. There seems to be some sucess using 5w40's, although my usage hasn't supported that yet.

My '88 runs 60 psi startup cold, runs a solid 60 psi hot on 5w40, whereas it fades on a 5w30 or 10w30 back to around 45 psi or so on 5w30's or 10w30's. Hot idle is 20 psi regradless of weight.

JeepZJ4.0 · Jul 1, 2004

I own a 95 Grand Cherokee as well. Does your GC have the 4.0L I6 or the 5.2L V8?

guitarrocks · Jul 1, 2004

Mine is the 4.0. Appears to be taken care of with 3k oil changes with Castrol GTX 10w-30. Everything else I have is in the Nissan/Toyota stable....so I see in the long run.

Bror Jace · Jul 1, 2004

There is a lot of discussion about Jeeps in this and other sections of the forum. Might want to do a search under "Jeep" and/or "4.0" here and look at all the threads that come up ... paying special attention to the ones in the Used Oil Analysis (UOA) sub-section.

--- Bror Jace

JohnnyG · Jul 2, 2004

GC = GC I don't see how you could go wrong.

safarikick · Jul 2, 2004

do you thing that 540 will be ok in a 2003 Grand Cherokee with 8000 miles on it

4.0 l

[ July 02, 2004, 11:24 PM: Message edited by: safarikick ]

JeepZJ4.0 · Jul 2, 2004

I'm using Delo 400 right now and its great stuff! It's 15w40. The pressure difference isn't that much. I changed the pressure sensor not too long ago so it somewhat accurate.

KW · Jul 2, 2004

quote:

Originally posted by safarikick:
do you thing that 540 will be ok in a 2003 Grand Cherokee with 8000 miles on it 4.0 l

Yes 5W40 would work very well in your 2003 4.0.

fasty · Jul 3, 2004

I am running 5w-40 on 1996 XJ 4.0L. It pretty runs good and much smooth.

My mom has 1995 ZJ and she running 5w-40 same setup as mine. I do maintence for my mom's jeep.

95 Jeep Grand Cherokee

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