What oil for 97 jeep 4.0 ?

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Hey everyone,

I may be picking up a 97 Jeep Cherokee with the 4.0L engine tomorrow. As I understand these are flat tappet engines and oil type is important for engine longevity. Which oil weight and type is best for these engines?

I live in MN and the engine currently has 158K on it. Dino fed it's whole life, they didn't specify oil type or weight.

Also, how about tranny and diff fluid?

Any other Jeep Cherokee owners care to chime in?

Thanks!
 
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I would use any quality namebrand sytnthetic 10w30 or 5w30.
Pennzoil platnium, Castrol, Mobil 1, Valvoline, ect. . .

The 4.0L is one of the best engines out there. I had one in my 97 wrangler.

Take care of it!!
 
i believe he was asking in relation to the flat tappets though. dont they have to have an oil with a certain amount of zddp? or am i just pulling that out of nowhere...
 
In my 4.0 I run Trop-artic 10w30 syn-blend. It is cheap and great for cold weather for you since you live up north. After much inquery, I am convinced that the flat-tappet thing is not an issue since the motor is already broken in and has stock weak valve springs. In a flat-tappet motor, it is important use something like Rotella for breaking in the engine or something like Valvoline VR1 in a flat-tappet high-performance engine with aftermarket stiff valve springs and a high-lift cam.

I hope this helps.
 
Originally Posted By: Klutch9
or am i just pulling that out of nowhere...


Pretty much. A 1997 street engine requiring an API rated oil can use API SM oil with complete confidence.

This engine will do fine on a stout 30, light 40.
 
Originally Posted By: Klutch9
i believe he was asking in relation to the flat tappets though. dont they have to have an oil with a certain amount of zddp? or am i just pulling that out of nowhere...




Rotella has plenty of ZDDP for about anything. A 4.0 with 158K should not have a bunch of spring pressure so just about any oil should work. I like XW40's in my Jeep to keep the hot idle oil pressure up.
 
Note...my '01 4.0 holds 6qt with filter...I would think the '97 would be the same. The trop-artic I use I get at SAM's for 25 bucks a case or something like that.
 
Originally Posted By: KW
Originally Posted By: Klutch9
i believe he was asking in relation to the flat tappets though. dont they have to have an oil with a certain amount of zddp? or am i just pulling that out of nowhere...




Rotella has plenty of ZDDP for about anything. A 4.0 with 158K should not have a bunch of spring pressure so just about any oil should work. I like XW40's in my Jeep to keep the hot idle oil pressure up.


thanks for confirming that. i was going to recommend rotella
 
Originally Posted By: FastSUV
Note...my '01 4.0 holds 6qt with filter...I would think the '97 would be the same. The trop-artic I use I get at SAM's for 25 bucks a case or something like that.


that is correct, my grandpa has a 97 or 96, cant remember... but it holds 6 quarts
 
Use the search feature- the Jeep 4.0 comes up frequently and there's a lot of recommendations and testimonials and maybe a few UOAs, IIRC.

I use Rotella T synthetic 5w40 in mine. But if your not an oil nit-picker, any quality 10w30 or similar oil, conventional or synthetic, will be fine. Heck, mine lived its first 120,000 miles with an owner who let Jiffy Lube take care of it with whatever swamp ooze they had in the bulk barrels. You can't kill a 4.0. Whatever oil you choose, go ahead and run a full-size filter (Purolator L3001 or equivalent) instead of the factory "shorty." More filter area => less pressure drop, less likely for the filter to go into bypass, and about a half quart extra oil capacity.

On to the transmission: you don't say if its the Aisin AW4 automatic or the AX-15 5-speed. The automatic came originally with Dexron III. Chrysler service departments now fill it with ATF+4. Dexron IV would probably work too, but I think its a little thinner than Dexron III or ATF+4. The AX-15 came with GL-3 from 97 to 99, and GL-4 or GL-5 gear oil is incompatible with its synchros. Oddly, the 96-down AX-15 was GL-5 compatible. Thankfully Chrysler ditched the Aisin 5-speed for the NV3550 in 2000 and later models. Chrysler now recommends servicing AX-15s with 10w40 engine oil. Most 5-speed Jeep owners prefer to bite the bullet and pay for Redline MT-90 or an equivalent, although a good synthetic 10w40 will serve just fine. Redline MTL and Royal Purple Synchromax are a bit on the thin side for that transmission, but I've heard of people using them. I'd stick with 10w40 or MT-90, myself.
 
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Originally Posted By: Chris142
My 02 with a 4.0 likes Pennzoil and QS 10w-30.


I had an older 4.0 Wrangler which was the quietest with QS or Pennzoil 10w30/10w40, cant go wrong with either IMHO.
 
Originally Posted By: Huie83
Hey everyone,

I may be picking up a 97 Jeep Cherokee with the 4.0L engine tomorrow. As I understand these are flat tappet engines and oil type is important for engine longevity. Which oil weight and type is best for these engines?

I live in MN and the engine currently has 158K on it. Dino fed it's whole life, they didn't specify oil type or weight.

Also, how about tranny and diff fluid?

Any other Jeep Cherokee owners care to chime in?

Thanks!


You don't have to worry about ZDDP in your XJ. I'm running SM rated GTX 5W30 in my 2.5L Wrangler trail rig for winter. My engine is beaten worse than you can imagine off road and survives just fine on SM oils. I like to run a SAE30 or 10W40 in summer, but if it's operated normally, 10W30 is fine. If it's had dino it's whole life, why change? Get the cheapest dino in the 10W30 or 10W40 flavor and she'll be fine.

Besides, it's a Jeep. You could poop in the engine and it will run.

Tranny fluid: Walmart HM tranny fluid

Gear oil: Supertech 80W90
 
Originally Posted By: Chris142
I have not seen any threads on the Jeep forums about stock engines eating the cam using the SM oil.


Bingo. The folks I wheel with lay the smack down and all of our engines and they haven't blown up (from lower ZDDP SM oil anyway
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I've owned seven I-6 Jeeps 258's and 4.0 L's for 25 years now, have a '04 Rubicon and I would't use anything that is not ACEA A-3 5W-40 in it, as lot of other Rubicon owners. Just my 2 cents.
 
Ok. What would you use, and what wouldn't you use? You obviously have 7 Jeeps of experience Bro., drop the knowledge already!

(Jeep Wave)

-A

Quote: I would't use any thing that is not ACEA A-3 5W-40 in it, as lot of other Rubicon owners. Just my 2 cents.
 
in my jeep 4.0l engine I have run and had great success with;
Motorcraft 15w-40
Mobil 1 10w-30 high mileage
Rotella t 5w-40
amsoil hdd 5w-30

a good solid zddp does perform better in our engines. I have been most happy with the mobil 1 10w-30 high mileage oils.
 
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