0w30 in Jeep 4.0L?

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jeepman3071

jeepman3071

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2000 Jeep Cherokee 4.0L, 106k miles, valvetrain noise only when warmed up. The Jeep is used to commute to college daily, 10 miles there 10 miles back. I live in CT and we've been having a rough winter.

I currently run Rotella 5w40 since I read on here that the UOAs show less iron wear with a 40 weight. I had a friend recommend using 0w30 in the Jeep since it helps with cold weather starting and mpg. Is there any advantage to running a 0w30 or 5w30 over the 5w40 Rotella?
 
Might help just slightly with super cold starting, but I wouldn't expect any MPG improvement. GC is relatively thick with high HT/HS, so it's not energy conserving.

I ran both oils (GC and Rotella 5w-40) in our old Jetta 2.0. MPG was about the same.
 
I'd do one of two things, neither of which is switch to 0w30 in a 4.0.

Most likely, I'd stick with RT6 5w40. The Jeep 4.leaker seems a match made for that oil. I really don't think a 0w30 is going to help much, if any, with cold-start issues.

Are you having any cold-start issues? If you are, then my next pick would be Mobil 1 0w40. Its got almost as much ZDDP as RT6, and almost twice that of most Xw30 oils.
 
I run 5W30 dino in my '89 XJ and 5W30 Quaker State Q-Torquepower 5W30 in my trail Heep. I lead a couple of snow runs the last couple of weeks (off road trips) and the 5W30 has held up fine.
 
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
 
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


Not sure I understand. The 5w40 is a lower viscosity on a cold start, and a 40w when at operating temp. I haven't noticed a difference in mpg when using it in the winter vs. in the summer.

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?
 
Pennzoil Platinum here on a 4.0 2000 XJ sport 4x4.

Currently the wife gets 16-20 mpg mixed driving.

No leaks, No consumption. Around 160k miles on the clock now.

10w-30.

And smooth running thru the whole winter.

Oh I forgot, Purolator P1 Filter.
 
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I ran 4.0 L jeep inlines for years. They do like the Rotella T 5w40. But if you want to go a 30. The oil I found it liked the best is the Amsoil series 3000 5w30 diesel or Mobil 1 10w30 High Mileage. Both of these oils were fantastic in the flat tappet 4.0L, they have a nice dose of zddp. I would run the Mobil if it were mine, I felt the Amsoil to be best but from a convenience perspective I would choose the Mobil HM, the difference is so little in my opinion. And yes I do feel those 30's to be superior to the rotella t.... I hope this helps you sir
 
I ran the Rotella T 5w40 for a time in my 88 Cherokee 4.0l. Since that time, I've switched back to a diet of 5w30/10w30 basic conventional oils.

I switched back after oil pressure started and stayed high, even when "fully warmed up" per the coolant temp, which is decidedly not the same as oil temps. On a 10 mile commute as indicated by the OP, I'd be surprised if that oil gets close to "operating temp" by the end of the commute and thus is thicker.

All that being said, in the 4.0 I never noticed any difference in fuel mileage between 5w40 and 5/10w30. My UOA's also showed virtually no difference in wear either.

The 4.0 is in general not terribly picky when it comes to oil. Millions of units ran lives well into the hundreds of thousands of miles using nothing but conventional 5 and 10w30's.
 
I'd run M1 0w-40 in it, just wait until Auto Zone runs a sale on it. I picked up 5 quarts with an M1 filter for 30 bucks last month.
 
Pablo as much as I hear good things about Amsoil its not real easy to find around here. Don't really want to have it shipped to my house.

123Saab, have you done any UOAs on that pennzoil platinum? I've never tried pennzoil before and I'm curious how it will do in the Jeep. My buddy loves it in his Ranger but he also has a different kind of engine. I could always switch to 10w30 or 5w30 PP and if I don't like it go back to Rotella.
 
Originally Posted By: jeepman3071


123Saab, have you done any UOAs on that pennzoil platinum? I've never tried pennzoil before and I'm curious how it will do in the Jeep. My buddy loves it in his Ranger but he also has a different kind of engine. I could always switch to 10w30 or 5w30 PP and if I don't like it go back to Rotella.


I'm sorry, I really dont do UOA's. (Tho I love to read other peoples UOA's)

I have nothing but good things to say about PP (Pennzoil Platinum) in the 4.0, but as others have stated you could run pretty much molasses in that engine and it wont quit.

In my humble opinion, they do tend to sludge a bit so I prefer PP. Keeps it clean.

There is no way PP will hurt your engine, I say why not run it for 3k and see how you like it
smile.gif
 
I forgot to add, my wife DOES have a lead foot on the hwy, and the truck still purrs like a kitten.
 
I've heard people say that GC is so far on the high side of the 30w they think of it as a 0w37.5w, which might be true but either way its going to work fine in that engine.

I would be interested to see the iron wear with the GC on your UOA after a couple runs, i would be willing to bet its going to be just a hair lower than the 5w40 your running
 
Here's some GREAT oil with "real" ratings/specs. To even meet ACEA spec the oil must pass very strict wear tests, cam wear being one of them. So if the bottle wears the ACEA badge you can rest assured that it will perform. Plus being "High Mileage" it has extra detergent and seal conditioners added along with more anti-wear additives. Does Ames oil meet any of the ACEA? or any spec for that matter?

I use the 10w30 because my rear main leaks a hair. 5w30 would be a great choice if you have no leaks.

http://www.mobil.com/USA-English/Lubes/PDS/NAXXENPVLMOMobil_1_High_Mileage_Oil.aspx
 
If cold start wear concerns you and you want to use a 40 grade oil, M1 0W40 as already mentioned is your ticket. JMO
 
The only problem I might see, is when the jeep cold. If its prone to leaks, as most 4.0's are the 0w30 might find its way out a little easier than a 5w30 Otherwise, at operating temps, I dont see a reason not to use it. It would help out cold starts nicely.
 
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