96/7 Jeep 4.0 Oil and filter.

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Originally Posted By: GT Mike
x2 on the oil caps being a pain sometimes. Put a little bit of Sil-Glyde or similar lubricant on the cap's O-ring and it'll come off a little easier. Eventually it'll be time for a new cap though...The plastic ratchets in them only seem to last so long before they're junk and the cap comes off in 2 pieces.


I'm probably going to replace it when I replace the leaking valve cover gasket this summer.

I was excited to use an oversized filter on the last oil change, but I'm going back to the Mopar filters after this. Engine just seems to run more quietly with them (probably all placebo, but whatever).
 
i have had a few jeeps with the awesome 4.0 inline 6 and i have been over 200k miles with a wrangler and she got ABUSED. used nothing but 5w and 10w30 dinos in it. change it every 3-4k miles and call it a day. they are very sold motors!! blows my mind why the quit making them bc everything else in a dodge chrystler jeep sucks monkey [censored]. that is one [censored] company
 
Best HM oil for 4.0 Jeep I have tried is Pennzoil HM 10w30...I have less than 100k on my 4.0L and I use it right now; although I plan to try max-life too
 
Originally Posted By: SL2
Guys, well my Sl2 the transmission blew, Im looking for another car, found a 96/7 Jeep 4Wd automatic. Went from 35Mpg to under 20.
shocked2.gif
Well anyways, It has around 140K miles, I really want to use some kind of synthetic, but being it has so many miles, do not think i will, only because i guess there are know to have to rear main seal leaks...

Anyways, this is the first time i have a suv, and have no idea what wt oil to put in it, I dont think its not 5-20/30 as they seem a little thin, How would 10-30/5-40/10-40 do?? again, i may use like ST synthetic, but it takes around 6Qts total.. What is the correct filter size? I dont think i need to worry about an over sized one, and again what would be a good OCI? 3-4K miles on dino 5K on synthetic? Ok so all in all

-Best oil, Dino or syn
-Best Oil Wt summer/winter
-Oil Filter size/number
-OCI's

Thanks!!



Don't fear synthetics. Jeep 4.0s seem to *love* Rotella T synthetic 5w40. I posted a ~5000 mile oil analysis on mine recently, and it was very, very good:

http://bobistheoilguy.com/forums/ubbthre...rue#Post1437776

We just changed that fill out yesterday at about 5500 miles. It could easily have made 6000+, but I'm not going to have a chance to do the work again for a while. My Jeep has just under 130k miles- just getting broken in for a Jeep 4.0! Don't call a 4.0 "high mileage" unless its got well over 200k on it. If you prefer an Xw30 oil, that's fine too. Factory recommendation is 5w30 or 10w30, but the new 0w30s would be even better. I plan to try a fill of M1 0w30 AFE in the fall to compare to this current fill Rotella, which is the first batch I've run that is the new SM rated formulation.

If you worry about the idea that PAO synthetics will cause old seals to leak (I don't believe it nor have I experienced it personally) then you still shouldn't worry because Rotella T Synthetic is a petroleum-derived group III+ synthetic (Shell XVHI base stock), not PAO.

I've already forgotten what the "correct" filter for a 4.0 is, because there's plenty of room to use a full-size (Purolator L3001, PL3001 or equivalent) and get more filtration area and an extra half-quart of capacity.

And I'll echo the comments about the silly oil cap being hard to remove. When my daughter and I changed the oil in the Jeep just yesterday (it'll be hers when she gets her license in the fall) and she couldn't get the cap off. I darn near couldn't either, so I coated the O-ring with silicone grease. Helps a lot.

Enjoy your "new" Jeep!
 
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I sprayed mine with brake clean as a rapid refrigerant. That thing began to worry me. It just kept spinning and clicking. Firmed up the tabs well, returning it to the one way clutch action it had, instead of the folding over torque limiting mechanism that heat turned it into.
 
I have a '96 Cherokee with 70K miles and have been using Syntec 10w-30. Getting the oil filter off is a semi-ball buster. I have just switched last week to PP 10w-30. I go 6 months between changes which equates to 5K miles or less.
 
Doesn't your Chero have a right angle mount? My son's '00 XJ does and quite a few others ..or is yours a Grand? He can fit a MEGA filter on there if he wants to. Much easier than the TJ's for filter service. Not that they're overly complicated compared to some.
 
Hi all, this is my 1st post and I was waiting for the right topic to respond to. I am also the proud owner of a Jeep Cherokee (2000) with the 4.0 6 banger and I have to agree with some of the posters on this thread, these motors don't seem to care what kind of oil you run in them. I am currently at 180,000 miles and for the last 9 years I have run every brand of oil and filter that you could think of on this rig. I drained the factory fill at 3,000 miles and have exclusively run synthetic since that time with oil changes anywhere between 6000-7,500 miles.

Since I am not loyal to any particular brand I use what is on sale and my latest (28th oil change) being Quaker State 5w-30 synthetic. While putting this latest entry into my oil journal I looked at previous entrys and over the last 9 years I have run the following synthetic oils: Havoline 10w-30; Mobil 1 5w-30, 10w-30 and 10w-40; Castrol Syntec 5w-50 and 10w-30; Quaker State 5w-30, 5w-40 and 10w-30; Pennzoil Platinum 5w-30 and 10w-30; Valvoline 5w-30 and Supertech 10w-30. Oil Filters used: Mopar, Fram, STP, Purolator, Mobil 1, WIX. Sorry for being long winded, I wasn't trying to hijack this post I just wanted to get my point across that these are great motors and will probably run half a million miles if they are maintained properly. If you are interested, here are a couple of links to Jeep Cherokee forums that have tons of useful info. Jeep Forums
#2 #3
 
SL2 -

You really have nothing to worry about; these 4.0 engines are pretty tough. Too bad C/D phased them out.

I raised my 1991 Cherokee (now with 145k miles) on Valvoline regular blend. Never any problems. Rear main seals on these (and many) inline-six motors require a frequent change; i.e. every 20-40,000 miles. Just the way they were designed.


Recently, I went to Pennzoil Platnium & it was even better (smooth, quieter, better gas milage, & temps were about 8-10 degrees cooler).

I run 10w-30 in winter and 10w40 in summer. Dump it in and go....no worries.


GL
 
I too have a Cherokee, 2001. 127K. There are some engines where a person really needs to think about what oil and filter to use on them. The Jeep 4.0 isn't one of them.

Find a good deal, and go with that oil. Run thinner in the winter and use a decent filter. You will be fine.

Sorry about the MPG, but congratulations on the Jeep.
 
Originally Posted By: HawkeyeScott
Find a good deal, and go with that oil. Run thinner in the winter and use a decent filter. You will be fine.


+1 on thinner in the winter. I ran 10W-30 last winter, and it never even got below 0*, but on a few of the colder mornings she made some very not nice metal-on-metal noises for the first few seconds.
 
Originally Posted By: Greg L
SL2 -

...Rear main seals on these (and many) inline-six motors require a frequent change; i.e. every 20-40,000 miles. Just the way they were designed. ...


GL


20-40,000 miles for the rear main? Sounds a bit much. I've more commonly heard the usual is more like 80,000 miles. My '88 XJ is on its second (currently at 112,000miles), but it was replaced after the Jeep sat nearly three years without being driven and suffered as a result (along with several other seals on the transmission, transfer case, and axles, which all were quickly weeded out...)

The usual statement is: My Jeep doesn't leak - it's just marking its territory. (BTW, mine does not leak at all!)
 
My rear main is original at 176K, but has been leaking since I bought it with 155K. I plan to replace it in the next few weeks.
 
My wife's has been seeping since near new. Always a dip ..never a drop (puddle). I'll have it replaced when I either do a trans/t-case swap/clutch ..or do a stroker mod. (need to fatten wallet first).
 
Originally Posted By: Greg L
Rear main seals on these (and many) inline-six motors require a frequent change; i.e. every 20-40,000 miles. Just the way they were designed.


20-40K? If your rear main needed seals that early, then either a)there is a groove worn into the crank or b) it wasn't installed correctly.

Every seal I've ever done on mine or friends has gone the distance.
 
I have about 130K on my 4.0. Right after I got it I tried 10W30 and the motor was noisy, then I went to 10W40 and it quieted it down a lot. I use Amsoil 10W40 and change it every October and it seems to be working well for me since 2001.
 
Originally Posted By: KW
I have about 130K on my 4.0. Right after I got it I tried 10W30 and the motor was noisy, then I went to 10W40 and it quieted it down a lot. I use Amsoil 10W40 and change it every October and it seems to be working well for me since 2001.


man i sure do wish jeeps were of more quality other than their motors. i would still own one today. my 01 grand cherokee had to be one of the worst vehicles as far as quality and reliability i have ever had. 85k miles on her and had to take that to a shop every 3 months like clock work.. my tacoma? [censored] perfect.
 
Originally Posted By: mikeg5
man i sure do wish jeeps were of more quality other than their motors. i would still own one today. my 01 grand cherokee had to be one of the worst vehicles as far as quality and reliability i have ever had. 85k miles on her and had to take that to a shop every 3 months like clock work.. my tacoma? [censored] perfect.


The early WJ's (particularly the '99) had some issues, mostly with all the electrical convenience stuff they stuffed in them. In particular, the heated seat elements tend to break, as does the A/C mixer door, very inconveniently located behind the dash. Brakes were also poor until mid-2002, when they changed to the Akebono style dual-piston calipers. The calipers are easily retrofitted to an older WJ, though. Chrysler sells a kit, it's about $300.

I'm not aware of too much else.
 
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