0w30 in Jeep 4.0L?

Pennzoil motor oil
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Originally Posted By: Bluestream
Originally Posted By: jeepman3071
Is there any advantage to running a 0w30 or 5w30 over the 5w40 Rotella?


I would not run the 40W in the winter. Thick as [censored]=poor MPG


You need to understand... this is a Jeep 4.0- therefore gas mileage sucks, period. Mileage the Jeep gets is not dominated by oil thickness, and in fact its so far down on the list of effects that it really doesn't matter. I notice NO change in mpg WHATSOEVER in switching from an Xw30 to RT6 5w40. What DID change was the wear metals in the UOA.
 
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Originally Posted By: jeepman3071

440Magnum: I'm not having any cold start issues yet. The Jeep does get parked outside but doesn't have any issues starting (also thanks to a yellow top optima). I know most wear occurs at start up so wasn't sure if there was something better for it than Rotella 5w40. Is there something I can do about the valvetrain noise? I know its normal but seems more audible when the engine is at operating temp. Would this have anything to do with the oil viscosity?


Hmm.. I'm hard pressed to think of any oil that would be better than RT6, Mobil 1TDT, or Mobil 1 0w40 for quietness and longevity of a 4.0. If you want to experiment to see if something helps the valvetrain noise, I'd try the 0w40. As others have said, a 4.0 isn't going to roll over and die even if you put the worlds worst over-the-counter oil in it- they're tough and not terribly picky. But in frequenting both the Jeep forums and this forum, most people report better UOA numbers and lower NVH (noise, vibration, harshness) with Xw40s in their 4.leakers. The 4.0 is a notoriously noisy engine, although smooth as silk vibration-wise and VERY long-lived. AMC and Chrysler built it like a tank (especially the post-96 ones with main-cap girdles), but never really bothered to put a lot of noise-deadening in it- no fancy multi-layer laminated valve cover and oil pan on that one. I always think of it as performing like a miniature Cummins diesel, and that's indeed about the shape of its torque curve.

If you want to see if thinner helps, I'd probably go with a high-mileage oil as others have recommended rather than, say, Mobil 1 Advanced Fuel Economy 0w30, simply to keep the higher additive levels. But if you want to try 0w30AFE, you're not going to hurt anything at all in the short term.



By the way, since your 4.0 is a 2000 model the thing I would REALLY watch for is coolant contamination in the oil. The "331" head casting used on 2000 and early 2001 4.0s is prone to cracking and allowing coolant into the oil, ESPECIALLY if it ever gets overheated. "Prone" is probably too strong a word- thousands and thousands have gone their whole lives without cracking, but a lot more of them do crack than earlier or later heads. If you ever notice the coolant level slowly dropping for no obvious reason, check the oil for contamination. most people just keep adding coolant and never notice the problem until their oil pressure gets down to nothing because the bearings are wiped out... and the engine still runs and sounds fine. :-/
 
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If it's not hard to turn over in the cold, I don't see a reason to go thinner. My mom's 4.0 has done fine in the cold (down to 15*, not sure if she's started it colder than that) with T6 in it. My Jeep cranked fine at 5* with T6. I didn't try it at -8* when I had a chance, but that's due to it having trouble vaporizing the fuel when it's very cold, so it probably wouldn't have started.
 
Thanks everyone for the great advice! I might try a xw30 just to see how it does. Pardon my lack of oil acronym knowledge but what is GC?

440Magnum:

I am a member over on Jeepforum as well as NAXJA and actually replaced my 0331 with a new Alabama cylinder head as a preventative measure, since two of my friends had theirs crack. This is my third Cherokee and want to have it a long time. My previous ones I just threw in whatever 10w30 I could find. The more I learn about my Jeep the more anal about maintaining it I seem to become, haha. My previous Jeeps leaked a bit but I've replaced most of the seals on this one so its just about leak free except for the oil filter adapter which weeps oil every so often.

I'll always think of Rotella 5w40 as the main oil to use, I just wanted to experiment with something different. The WalMart near me only seems to have one gallon bottle of Rotella everytime I'm there (if they aren't out of stock) so its kind of a pain to have to drive to several different places. For some reason the Rotella at Advance is about twice the price of WalMart...
 
Originally Posted By: jeepman3071
Thanks everyone for the great advice! I might try a xw30 just to see how it does. Pardon my lack of oil acronym knowledge but what is GC?

440Magnum:

I am a member over on Jeepforum as well as NAXJA and actually replaced my 0331 with a new Alabama cylinder head as a preventative measure, since two of my friends had theirs crack. This is my third Cherokee and want to have it a long time.


Awesome... sorry I was "preaching to the choir" as they say :-)

I've given some serious thought to popping an Alabama head on my 2001 for the same reason, but instead I'm taking the "watch it closely" approach. Its not my only transportation, so if I have to park it and wait to do the head, its not that big a deal.

Experimenting with oils is probably a good idea, and like I said a 0w30 won't hurt it. Let us know how it does, in fact.

As for finding Rotella for a good price- do you have a Pep Boys near you? They seem to have RT6 for the same price +/- a buck or two as Mall Wart all the time in my area. I don't buy *parts* from Pep Boys, but in my area at least they're an OK source of oil and filters.

Oh, and "GC" on here is "German Castrol." Its actually Castrol Syntec 0w30- if you look on the label its the only Syntec that says "made in Germany". Its a pretty robust and thickish 0w30 that was the darling of this forum a couple of years ago.
 
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GC = German Castrol, gotcha. Unfortunately there isn't a Pep Boys that close to me, the nearest one is 45 minutes away and they seem to have wierd hours. I'm limited to Advance Auto, WalMart, and NAPA. NAPA seems to be more expensive than Advance. I know I've seen Pennzoil so I'll give the platinum a try and let everyone know how it goes.

I recommend the Alabama Head. It seems well built and they shipped it very fast. I was doing the "watch the coolant level like a hawk" thing for awhile but I need my jeep to get to classes. I figured it was worth fixing it when I had time over break since with my luck it would probably crack at a really bad time.
 
Honestly, the 0331 heads, while more prone to cracking than the others, are far from guaranteed to crack. As long as they don't get overheated, most of them will be fine, only some will crack.
 
Originally Posted By: rslifkin
Honestly, the 0331 heads, while more prone to cracking than the others, are far from guaranteed to crack. As long as they don't get overheated, most of them will be fine, only some will crack.


...Says the guy with a 5.9 in his Jeep :-p

Seriously, I agree completely. On the other hand, if an XJ with a 331 head were my ONLY transportation, I'd probably do the Alabama cylinder head. They're amazingly cheap and have a very good reputation. Especially since a head swap on a 4.0 is one-Saturday job.
 
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Jeepman3071, I have a 2004 GC, same engine, with around 97k. I had a lot of lifter tick develop here in VA starting last November. Previously I'd used 10w30 year round, but this year it's been comparatively cold - 20's for a couple of weeks in November, and that's when the lifter tick developed. I changed to 0w30, and the lifter tick has all but gone away, even though we've had teens for 3 continuous weeks in Dec/Jan.

As far as the 10w40, I've always used Xw30, never saw a need to go thicker - and every bit I've seen online about it says the 4.0 likes 30 weight.
 
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Originally Posted By: Kuato
Jeepman3071, I have a 2004 GC, same engine, with around 97k. I had a lot of lifter tick develop here in VA starting last November. Previously I'd used 10w30 year round, but this year it's been comparatively cold - 20's for a couple of weeks in November, and that's when the lifter tick developed. I changed to 0w30, and the lifter tick has all but gone away, even though we've had teens for 3 continuous weeks in Dec/Jan.

As far as the 10w40, I've always used Xw30, never saw a need to go thicker - and every bit I've seen online about it says the 4.0 likes 30 weight.


I hear most Jeep 4.0 owners discussing a lifter tick on start up. Mine is actually pretty quiet on start up and seems to make more valvetrain noise once its warmed up a little. Once in overdrive it is perfectly quiet but seems to make the noise around 1800 RPM, then again between 2000 and 2500 RPM. Sometimes it doesn't make the noise at all. I know these motors are noisey and I'm probably just anal about noises, considering I could hear my cam position sensor ticking when it was going bad. The jeep mechanic was impressed I could even hear it.
 
440 - I've still got an interest in Jeeps with the 0331 head. My mom's 99 Grand Cherokee 4.0 has an 0331.

Jeep 4.0s do simply make some noise at times. How much and when seems to vary based on the particular engine though. My mom's has very little valvetrain noise (just a tiny bit of clatter for a couple minutes in very cold weather), but it has some mild piston slap during warmup. My friend Matt's 4.0 is actually pretty quiet, I haven't heard any strange noises out of it yet.
 
I'll add my $0.02 since I'm also a 4.0L owner in the form of a '99 XJ. I've had mine since 53k miles (now at 90k) and the PO ran Mobil 1 10w30. I've ran MaxLife 10w30, Rotella T5 10w30, and currently Pennzoil High Mileage 5w30.

I'm not really a believer that the 4.0L requires a 40 weight oil or extra ZDDP. While it does have a flat tappet cam, the spring pressures and lift amounts are pretty mild. I do think that a thicker 30 weight is probably a decent idea. I'm not against 40 weight oils, as I do run 15w40 in my AMC 360 powered Grand Wagoneer, but just not convinced its necessary in a 4.0L.

I had the Rotella T5 in it this winter when temps got down to near 0 degrees in the morning. The Jeep cranked and started, but I did have a rattle for about a second that I didn't love. I also had a piston slap (or lifter knock, hard to tell) until the first time I accelerated. I decided to go for a 5w30 this change because of the temperature. I will say that with Pennzoil High Mileage 5w30 that I haven't gotten any start-up rattle and the piston slap seems to be reduced.

I think High Mileage oils are a good choice in this engine, even if it isn't high mileage. They tend to be on the thicker end of the viscosity range, and that's what this engine seems to like.
 
When I swapped my mom's over from 10w30 to T6 5W-40 it definitely got a bit quieter in terms of winter starts. The 40 isn't needed, but it doesn't hurt, and these engines couldn't care less about the extra thickness once warmed up. It doesn't feel sluggish or anything.
 
Just to add to the 'experiences'....I worked with a guy for a year at a Walmart Tire and Lube Express that had a 2002 Wrangler 4.0.

It was his DD during the week, and on weekends, he did heavy-duty off-roading with it - deep mud trails in the bush. He was also the guy who pulled out others who got stuck. Needless to say, that Jeep got run HARD.

I asked him about oil and changing it on his Jeep, and he just used whatever conventional 10w30 oil was cheapest when he needed a change, and changed it ever 3-4k miles. He gave me a ride to work in it on several occassions, and I'll tell you, it was a very quiet engine. I was suprised, b/c I though with the use, it would be noisy, but it was really quiet and smooth.
 
Originally Posted By: 47HO

Have you tried a different oil filter to see if that helps quite the noise?


I've tried a few different filters. Mopar, NAPA silver, Purolator Pure One, and Mobil 1. The noise seemed to be the same.
 
To be quite honest, these engines last usually longer than the Truck they are in.

Thousands of them are still on the streets/trails today and not that many are even maintained all that well.

I'm glad that the OP chooses to baby it, I sure baby the one we have, They are the last of their kind.
 
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