01 Jeep Grand Cherokee 4.0 engine, Rotella T6 5W40

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Originally Posted By: Zaedock
I agree with Gokhan, Don. I've settled on using 5W30 SOPUS grpIII syns in my Jeeps and it seems to work well. Much more free revving than a 40 wt, which is important when pushing 600+lbs of off road tires.





But my UOAs when I was using 10W30 PU were not as good as Rotella T. Maybe it was more late break-in wear than the oil.

I do not do a lot of free revving and have stock tire size in a M&S.
 
Originally Posted By: Donald
Originally Posted By: Zaedock
I agree with Gokhan, Don. I've settled on using 5W30 SOPUS grpIII syns in my Jeeps and it seems to work well. Much more free revving than a 40 wt, which is important when pushing 600+lbs of off road tires.

But my UOAs when I was using 10W30 PU were not as good as Rotella T. Maybe it was more late break-in wear than the oil.

I do not do a lot of free revving and have stock tire size in a M&S.

That was just the break-in effect as you said.

xW-40 is unnecessarily too thick and CJ-4 HDEO seems to be corroding your copper -- again, you're using a CJ-4 HDEO unnecessarily for a gasoline engine. Note that "unnecessarily" means "harmfully" in this context.

The right oil for your engine is a fully synthetic SN/GF-5 5W-30 (not even 10W-30 in your climate). Just pick up your favorite brand and line of fully synthetic SN/GF-5 5W-30.

PS: Old owner's manuals recommended 10W-30 but not 5W-30, but this is only because SAE J300 revisions didn't put HTHSV minimums on oils back then. SAE J300 has been revised for quite long to include HTHSV minimums (2.9 cP for xW-30) and all xW-30s should perform similarly in demanding conditions now. So, 10W-30 instead of 5W-30 or 0W-30 is an obsolete consideration. Moreover, a fully synthetic 5W-30 often gives you some added degree of confidence with respect to permanent oil shear (viscosity loss) in comparison to a conventional 5W-30. You can try both conventional and fully synthetic 5W-30 to see if your UOAs show any difference with respect wear and permanent oil shear.

Here is a completely obsolete -- thanks to revisions in SAE J300 -- oil-viscosity-recommendation chart for 1997 - 2000 Chrysler full-size trucks:

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I am not in a position to dispute your statement about Rotella T6 and copper, but it would seem that Rotella T6 is used in many engines with oil coolers that have a lot of copper in them. Wouldn't they have the same issue.
 
I email Shell - their response below:

Dear Sir,

There is noithing in the Rotella T6 additive package that would cause an increase in the level of copper in the oil . I would recommend talking to the engine rebuilder about possible sources of copper contamination.

Regards,

Shell Technical
 
Well, oil coolers don't experience wear. Shell tech support will say anything. My recommendation for you is to go back to 5W-30. You'll not only get better UOAs but also have a much smoother-running engine, which is even more important.
 
Thinner oils are not the answer in the Jeep 4.0 but Donald already knows that.

I find the engine builder's process and Shell's answer much more plausible, been far too many stellar UOA's with T6 on here to think it is suddenly eating up this engine.
 
Originally Posted By: KCJeep
Thinner oils are not the answer in the Jeep 4.0 but Donald already knows that.

I find the engine builder's process and Shell's answer much more plausible, been far too many stellar UOA's with T6 on here to think it is suddenly eating up this engine.


+1

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So what is the verdict for the next change beyond the Rotella T6 thats in there now? To add some spice to the topic I added a 12 oz container of the older Auto-Rx to the current oil.
 
You could try a conventional and a shorter OCI, PYB or Defy would both be great choices. You might be surprised!

I am going through some Edge I bought on BOGO but I can't wait to get back to good old PYB in mine.
 
Originally Posted By: Donald
So what is the verdict for the next change beyond the Rotella T6 thats in there now?

Personally, I can't see any problems with the T6 in the first place.
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Originally Posted By: Donald
So what is the verdict for the next change beyond the Rotella T6 thats in there now? To add some spice to the topic I added a 12 oz container of the older Auto-Rx to the current oil.

My recommendation:

(1) You don't need Auto-Rx -- especially for a newly rebuilt engine, it will do more harm than good.

(2) Drain and refill with M1 5W-30 SN, PP 5W-30 SN, or similar high-quality 5W-30 SN next time.
 
Originally Posted By: Donald
So what is the verdict for the next change beyond the Rotella T6 thats in there now? To add some spice to the topic I added a 12 oz container of the older Auto-Rx to the current oil.


I'm not sure how a product meant for cleaning will improve wear. Unless you figure your brand new engine already has deposits.

Personally I'd do whatever kcjeep suggests. He's got used oil analysis to confirm his plan,so absent of any other data I'd go with his plan of attack.
 
Don,

I have been using synthetic HDEO 5w-40/15w-40 or 10w-40 oil in my 2001 Jeep Cherokee for 218,000 miles. The original owner used Mobil 1 10w-30 for the first 42,000 miles. Between 100,000-160,000 miles I used Castrol GC 0w-30. My oil changes have been between 9,000-20,000 miles, average about 13,000 miles. When the mechanic pulled the head at 160,000 miles he asked me if it was the original motor will all those miles because there wasn't much wear. My advise is to continue to use whatever engine oil you like. I prefer xw-40 or a thick xw-30 in mine as it seems to keep the (iron) wear down. I dismiss the arguments that HDEO should not be used in a gas engine.

Brian
 
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I don't think for a second it is the oil. HDEO's work very well in the old-school Jeep 4.0L, which has more in common with an AMC I-6 than even Chryco would like to admit.

Probably a sealant/grease of some kind washing out. It can take a while.

Auto-Rx won't hurt either - no, the engine doesn't need cleaning, but the stuff adds esters to the oil mix, which helps with oiliness and metal cling.
 
Originally Posted By: brian
I prefer xw-40 or a thick xw-30 in mine as it seems to keep the (iron) wear down. I dismiss the arguments that HDEO should not be used in a gas engine.


My preference as well. IMO Donald is already running one of the best oil possible choices, this engine just seems to generate higher "wear" numbers than most.
 
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