Which Oil For : 1995 Jeep Cherokee I-6 Cylinder?

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Just picked up a good condition 1995 Jeep Cherokee I-6 Cylinder XJ with 190,000 miles on it . I believe new it called for 5W30 oil ...Mechanic friend I talked to advised the following : * Might want to stay away from synthetic oil if your not sure what the previous owner(s) used ... High mileage Jeep I-6 cylinder engines are prone to real seal oil leaks with synthetic oil. * With 190K miles on the engine you may wish to go up to 5W40 in winter and 10W40 or 15W40 in the summer ... Don't overlook a HD oil like Rotella - will play nice in your high mileage 1995 Jeep I-6 cylinder engine . Your thoughts and advice ? - My knowledge of jeep engines and any engines in general from 1995 is slim .
 

ChrisD46

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PYB 5W30 or 10W30 would definately be on my short list ! I'm completely ignorant regarding HD oils like Delo or Rotello - what series & weights would be a possible good fit for this Jeep engine ?
 
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4.0 will run on almost any decent oil-I have 218K on mine, I run Defy 10W40 (with the extra moly) in summer & have used MaxLife synthetic 5W30 in winter, only light seepage from the rear main & timing cover seals.
 
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Originally Posted By: bullwinkle
4.0 will run on almost any decent oil
^This. I've got three Jeeps that have the 4.0 engine. Of course, they all have the flat tappet lifters. If you were asking about oil to break them in, my advice might be different, but you can run about any name-brand oil in these engines. I'm currently running $2/quart TropArtic in two of them and the other one is running on my last jug of FAR G-Oil. Sleep without worries.
 
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Pm KCJeep or maybe he'll respond. When it comes to jeeps he's one guy who's shown me here on the forum that he knows what he's talking about. Not that the above recommendations aren't sound,it's just that kc has proven himself in my eyes. Personally I'd run a 40 grade in it,with a can of liqui-moly motor oil saver for the potential rear seal issue,and just all the gaskets in general.
 
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I've owned 3 vehicles with that engine. That, plus from readings here on BITOG makes my suggestion Rotella 5w40. But I also had good results with Valvoline dino and ST Synthetic 5w30 at a 5k OCI, with about 60% highway driving. Down in GA though, cold temps won't be an issue so a solid 10w30 wouldn't be a bad choice. Yes at 190k you may get a rear seal leak, but it would have been there eventually no matter what oil you use.
 

ChrisD46

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Thanks for the replies ! Looks like PYB , QS Defy and Rotella Triple T dino oils in 10W30 would work year round ...Anyone drop down to a 5W in their Jeep 4.0L I6 engine for a winter OCI when temps may dip down into the occasional teens at night ?
 
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I have a 2001 Cherokee with 198,000 on it. I've tried several oils but it seems the quietest on 10w-30 High Mileage...Super Tech from Walmart is excellent so are any of the name brand HM 10w-30 oils. I tried 10w-40 I early in the summer but still quietest on 10w-30.
 
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I've owned my 87 4.0 since new. The owners manual specs 10-40, 20-50 above 32f. I run Rotella 15-40 in summer, Mobil 10-40 in the GA "winter". It has a drop or two rear main seal leak. On these engines you also want to check the oil filter adapter o rings and valve cover gaskets for leaks. The way the engine sits, all oil seepage will flow back and might be taken for a RMS leak. I recently added LM MOS2, and it idles and ticks over almost like a sewing machine. Best it's sounded in the 130k miles I've put on it!
 
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Originally Posted By: ChrisD46
Thanks for the replies ! Looks like PYB , QS Defy and Rotella Triple T dino oils in 10W30 would work year round ...Anyone drop down to a 5W in their Jeep 4.0L I6 engine for a winter OCI when temps may dip down into the occasional teens at night ?
You've done some reading! Those are fantastic oil choices right there. Your Jeep was spec'd for 10w30 but probably allows 5w30, I doubt you need it at all in your climate. I am convinced the Jeep 4.0 will do best on a thicker 30 or lighter 40 grade, but as mentioned it'll run near forever on about anything. I'd add 10w40 Maxlife to your list of possibilities as well. If you like quiet save yourself the trouble and just go PYB. I do run 5w30 in the very cold months but that's it, much thicker the rest of the year. Currently running Pennzoil HM which is a thick 30, got my best UOA so far on Pennzoil 10w40 though.
 
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I bought a new one back in '96. Used 10W30 M1 year round for the first 120K miles. My son is driving it now. He's put about another 120K on it. He's been using mostly 0W40 M1. Internals are untouched and it still runs well. Does leak a little, mostly from the rear main.
 
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Originally Posted By: ChrisD46
Thanks for the replies ! Looks like PYB , QS Defy and Rotella Triple T dino oils in 10W30 would work year round ...Anyone drop down to a 5W in their Jeep 4.0L I6 engine for a winter OCI when temps may dip down into the occasional teens at night ?
Like I posted above, 5W30 Maxlife synthetic worked fine in winter in mine, hot (indicated) oil pressure has always been a little low on mine or I would run a 5W30 HM oil year-round. If you search 4.0 UOAs you'll find that the PYB ones have been really good (low iron) & the Mobil 1 ones have been higher in Fe for some reason. Use a filter with a silicone ADBV too, you'll have quieter cold starts.
 
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I've never run any UOA's on the oils I have used in my 96 XJ, but I can say with certainty that the quietest it ran was on Mobil Super HM. The liveliest the motor has felt was on Peak 10w30 conventional. Gulfpride 5w30 also ran great in my 4.0. I have run a lot of Peak 10w40 SN because I got it very cheap. I definitely prefer the way the vehicle runs on 30 weight engine oils.
 

ChrisD46

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Love hearing the Jeep 4.0L XJ owners talk about their oil favorites ! Will add Mobil and Super Tech to the list (WM less than 1 mile from house) . Will add the oil filter will be WIX or NAPA Gold ... Lastly curious about OCI's with the big 4.0L sump (6 qrts) : Is 5,000 miles OCI OK for average suburban driving style ? No manual with the '95 Jeep so no idea what Jeep stated for normal OCI and severe OCI ?
 
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Castrol 10w-30 here on 98 TJ 4.0L w/86K miles. No leaks at all.Motor sounds and runs good. Keep an eye on the upstream Ox sensor though if milage goes down.
 
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