So if the Jeep 4.0 likes thicker oil.......

[Chris142]

You guys say that 40wt shows better wear numbers in this engine even though 30wt is recomended. I have 3 cases of 20w-50. Ok for my 02 jeep w/22k on it? Or should I use the last of my 10w-30 I have? Sposed to be 80 degrees tomorrow, summer temps are 110 deg.

 

[SteveD2]

I would wait until summer to use it, although I wouldn't use it at all. It's probably just fine, but it's still a little on the thick side. The 20w is what would worry me most, alot of people are using <b>5w</b>40 in this engine.

 

[JohnBrowning]

IF it is 80F out you have no problems running 20W50. I would save the 10W30 for winter use or use it to top off with. You might also consider the 10W30 for lawn equipment!

 

[Greaser]

What brand name of 20W50 is it?I use 15W50 Mobil in my Cherokee last summer as an experiment to see if the piston slap would be a bit quieter...it worked...and had NO problem running that weight in the 4.0L around here in summer...use 10W30 Mobil in winter but next oil change I'm going to give the Delvac 1 in 5W40 a try...I think it's a more sheer stable oil and might be a bit better in the piston slap area...worth a try anyways..I really like the way the Delvac behaves in my TJ's 4.0L engine so I'll give it a try in the XJ.

 

[97XJ]

How does GC 0w-30 do with this engine?

 

[Pablo]

Apple Valley? You could use up the 20W-50 from now to Nov. Dino, right? I just wouldn't push the OCI much with a viscosity enhancer filled dino 20W-50.

 

[Chris142]

quote:

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Originally posted by Greaser: What brand name of 20W50 is it?

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I know that I have a case of Havoline/Chevron 20w-50 dino and 6 qts of QS dino. Might have more than that but I can only remember so much I have a case of SuperTech 10w-30 dino to.

 

[TheTanSedan]

Rule of thumb is no thicker than necessary. I felt that the DELVAC 5W-40 is likely a "best" overall choice (assuming l-o-n-g o.c.i.), but my numbers have been in favor of 30w in an area a helluva lot hotter than the majority of CA. Though it will be a while, our 2001 Cherokee will be posting some numbers on a new combo under Terry Dysons direction. Mileage will be at least 7500-8000. Here's the link to the last one recorded: http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=3;t=000646 (M1 0W-40 seems to be pretty much a "thick" 30w)

 

[Chris142]

I have a case of Super tech 10w-30. Case of Havoline sae 30. Case of Havoline 20w-50. 6 qts of Napa (valvoline) 20w-50. 6 qts of QS 20w-50. I don't have any long filters for my Jeep. I do have a super tech#16 and a couple of the equivelent Proline ones. Now you guys got me thinkin. Maybe try some Delo 15/40 or Pennz 15/40 since I need to go buy a filter

 

[MNgopher]

FWIW, if this is the 4.0l or 2.5l, my owners manual from my '88 Cherokee approves the use of 20w50 when outside temps will be above 32F. The charts recommend everything from a 5w20 to 20w50 depending on temp. I think the moral to the story is the Jeep will generally run fine so long as it has oil in it.

 

[Bror Jace]

"I think the moral to the story is the Jeep will generally run fine so long as it has oil in it." True ... but that's never good enough for those of us at BITOG who feel that extremism, in the name of exceptional UOAs, is no vice. Chris, if you run a 20W50 for 4,000 or more miles, please post a UOA. I don't think we have one for a Jeep 4.0L running 20W50. I still think Pennzoil's 15W40 is the most cost effective oil for this engine in most climates. The ~180PPM of moly should also help with any piston slap noise. --- Bror Jace

 

[JeepZJ4.0]

For those who run the 40wt in their 4.0L Jeep engines.. does it run better or feel better with the 40wt compared to the 30wt? I'm using that Texaco Synthetic oil that was on sale at Big Lots. I heard it was good but I think it is too thin for the 4.0L. I'm going to use the last 6 quarts next week and change it out in 2000 miles.

 

[Chris142]

quote:

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Originally posted by Bror Jace: "I think the moral to the story is the Jeep will generally run fine so long as it has oil in it." True ... but that's never good enough for those of us at BITOG who feel that extremism, in the name of exceptional UOAs, is no vice. Chris, if you run a 20W50 for 4,000 or more miles, please post a UOA. I don't think we have one for a Jeep 4.0L running 20W50. I still think Pennzoil's 15W40 is the most cost effective oil for this engine in most climates. The ~180PPM of moly should also help with any piston slap noise. --- Bror Jace

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Mine only has 22k on it....No piston slap yet. I did lots of shopping in an attempt to find a decient filter. I ended up at Napa with a 1515. In my travels I found QS oil on sale. I bought 10w-40. I know that it will break down quick and thin out. I'll drain it around 2500-3k and send of a sample. That way we will get a QS UOA, we don't have many here and I'm curious as to wheather it has lots of good stuff in it.

 

[MNgopher]

I honestly have not noticed a difference in engine noises or performance since switching from 5 or 10w30 to Rotella 5w40. Of course, my 4.0 slaps a bit anyways... Not that it matters... Cold starts (and I mean -20 F or so) have been more strained than when using 5w30 in the winter.

 

[Chris142]

quote:

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Originally posted by MNgopher: Cold starts (and I mean -20 F or so) have been more strained than when using 5w30 in the winter.

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I don't have that problem.....I live in the southern tip of Death Valley!

 

[Calvin]

Chris142, I work very close to an auto pars store that I have been buying from here in the Bay Area since the early 70's..so I know these guys.We got to talking about oils and they looked up thier sales history.... 20W-50 is thier 3rd best seller.It's not that they sell it... people buy it. Alot of people live in the Central Valley where it often gets to 110 or higher and commute in the cooler Bay Area so they need an oil that can work deciently from a summer range of say 60 to 115 deg F. Personally I have never used 20W-50 or any 50 weight oil so I cant say anything but I know several people who use nothing but 20W-50. I cant recall anyone ever talking about problems useing that oil in this climate....and with your climate being even worse than the Central Valley I would think you shouldnt have a problem.

 

[Bror Jace]

"20W50 is their 3rd best seller." I don't doubt that for a second. I know 10W40 is up there too. It's just that the people buying most of these weights don't really need that viscosity and their engine(s) would be better off with something thinner and more stable. But as has been said before, most engines are robust enough to put up with a less-than-ideal weight of oil. But BITOG folks are a superior breed and that sort of misapplication is rarely acceptable. --- Bror Jace

 

[Calvin]

quote:

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Originally posted by Bror Jace: "20W50 is their 3rd best seller." I don't doubt that for a second. I know 10W40 is up there too. It's just that the people buying most of these weights don't really need that viscosity and their engine(s) would be better off with something thinner and more stable. But as has been said before, most engines are robust enough to put up with a less-than-ideal weight of oil. But BITOG folks are a superior breed and that sort of misapplication is rarely acceptable. --- Bror Jace

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I certinally agree with you.The majority of people who use 20W-50 ...could certinally use a lighter oil.... no question.... Even I who used straight 30 weight oils for over 30 years here never gave a thought to a 50 weight... not in the Bay Area at least... Even with straight 30 weight cold starts were never ever a problem and contrary to popular belief ( at least with SBC and BBC engines ) it only takes a couple of seconds to fully circulate oil... I dont know what it takes for a Jeep engine tho. But the Calif deserts can be down right brutal at times.I used to live in Southern Calif and in some area's it can get to 120 degF . But again I agree that for most non desert type use 20W-50 is abit much.

 

[MNgopher]

Interesting to see what grades sell best where. Based on what I've been seeing lately, I don't think anyone moves much 10w40 anymore around here. Two stores I was at tonight still had SJ 10w40 Purebase Pennzoil on the shelves (in cases with Steve Park driving the Pennzoil Nascar car). The Diesel oils in 15w40 and 5w40 move well though. Both stores turn over 5w30 and 10w30 faster than one would believe (and I'm talking pallets here - not a case here and there!).

 

[Santo Fontana]

You might as well use all that oil. I say mix it and adjust your ratio according to vis on the uoas. I would do 4:3 10w30:20w50 at first.