2000 Jeep Cherokee 4.0L, PYB 5w30, 3500 miles

[jeepman3071]

2000 Jeep Cherokee 4.0L with 132k miles (currently).

Oil was Pennzoil Yellow Bottle 5w30 run for 3,500 miles
Filter was a Mopar MO-090
This Jeep sees mostly short trips. My commute is 7 miles to school. It rarely sees any highway driving.

Makeup: 1/4 quart (rear main seal leak)

Comments:

"JOSH: Thanks for the notes about the make-up oil. Even if everything's fine, 1/4 quart of makeup oil isn't a
concern for most engines, and that's not bad at all considering you had a rear main seal leak. As far as we
can see in this report, everything looks great. All wear metals are at or below average levels, which is good
since averages are based on a slightly longer ~4,300-mile oil run. We didn't find any evidence of harmful
contaminants like fuel, dirt, or moisture, and the TBN of 2.6 shows a good amount of active additive left. Try running 5,000 miles next oil. Nice Jeep!"


Code:
OIL PYB 5w30 Universal Averages

MILES IN USE 3,503 4,300

MILES 131,203

SAMPLE TAKEN 3/2/13



ALUMINUM 3 3

CHROMIUM 1 1

IRON 23 27

COPPER 2 4

LEAD 1 3

TIN 0 1

MOLYBDENUM 258 67

NICKEL 1 1

MANGANESE 0 1

SILVER 0 0

TITANIUM 0 0

POTASSIUM 1 3

BORON 89 45

SILICON 11 11

SODIUM 10 35

CALCIUM 2419 2100

MAGNESIUM 18 124

PHOSPHORUS 787 723

ZINC 914 868

BARIUM 0 0





Values should be

INSOLUBLES 0.3
WATER 0
FLASHPOINT ºF 410 >365

SUS VIS 210ºF 56.2 55-62

cSt @ 212ºF 9.11 8.8-11.1

Fuel
Antifreeze 0 0

TBN 2.6 >1.0

 

[Garak]

Thanks for the post. Things are working exactly as they should be for you.

 

[Donald]

i would go to 5K. Why not PP, its not that much more at Walmart.

Try some Auto-Rx Plus to see if it will help the real main seal leak.

 

[SwampSurvivor]

Does your rear main leak drip right on the exhaust pipe?

 

[440Magnum]

Looks pretty good. Here's one of my UOA's with Rotella T Synthetic (previous name for T6) for comparison:

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1734164

 

[dnewton3]

Looks fine. I'd double that OCI for starters. And no, you don't need PP or PU to get there, either; the PYB is fine and will pay itself off much sooner.

 

[KCJeep]

Thanks for posting! Jeepman3071 and I have been working on a dual project and this is his end. Well done, and it looks good.

My only concern is the PYB is down to a heavy 20 grade at 3,500 miles, but it hardly appears to have been a problem.

Both of us have noted the PYB 5w30 runs exceptionally quiet in the venerable 4.0.

I'll be posting a UOA on Castrol HM in a few days. I also wonder how a heavier blend of PYB would do???

 

[ottotheclown]

Originally Posted By: dnewton3
Looks fine. I'd double that OCI for starters. And no, you don't need PP or PU to get there, either; the PYB is fine and will pay itself off much sooner.

 

[k24a4]

My girlfriend has a '97 Cherokee with 240,000 miles. She is a Jiffylube gal, which means she is also using Pennzoil. She says she "thinks" they use a 4x4 oil?

She changes it every 3-4k but I've been working on her to extend, in the name of Bitog.

 

[k24a4]

She's owned it since new.

 

[Chris142]

Put a 15w40 oil in it and watch the iron get cut in half.

 

[KCJeep]

Originally Posted By: Chris142
Put a 15w40 oil in it and watch the iron get cut in half.


I've certainly not seen that in the UOA's I've looked at. Have you seen the study done by 1bolt on Jeep Strokers? It also shows no practical difference between 30's and 40's regarding iron or other "wear" metals. 1bolt's study is below, no study is perfect but he did a great job IMO:

It looks like there's is no significant wear or reliability benefit to running heavier 40 weight oils in our engines compared to the lighter 30 weights. If you didn't already know; the prevailing opinion is that our I6 wears less and lasts longer with 40 weights (10W40, 5W40, 15W40 etc.) this seems to be the conventional wisdom especially on the number 1 motor oil site http://www.bobistheoilguy.com. Ask any expert on their forum and they will tell you the Jeep inline likes a 40w and especially with respect to iron wear, which its famous for high levels of. I used to pimp 20 weights, but such was the weight of opinion on BITOG that my last two fills were 10W40. This was probably one of the factors motivating me to take a hard look, I don't like following the herd without looking for my own evidence.

Instead of my usual long detailed preamble explaining all the mind numbing data harvesting and analysis I did to figure this out. I'm just stating it out front for anyone interested in the lowdown; but who just isn't as geeked up about the subject as I am. If you're wondering what a UOA is and how in the world I came up with these numbers keep reading, after the colorful pictures .

First the numbers



The Above are straight averages, in others words total wear metal numbers for each type of metal (in PPM) divided by the number UOA's irregardless of average miles per UOA. Below are adjusted averages, where the number of samples was balanced to arrive at a similar amount of miles per UOA (throwing out the highest and lowest mileage samples) then dividing the wear metals by the number of samples.







These two show you a gross average of what each UOA looked like. I tried running the metals divided by only mileage but had a hard time coming up with meaningful numbers dividing hundreds of thousands of miles into a couple hundred parts per million (no math wiz here that's for sure).

The opinion I've formed is that there's no sense in running 40w oils. lighter 30w's will improve power and gas mileage slightly. And from the looks of things will provide the same level of protection, they will get to parts quicker on cold starts and they will stay on parts longer when parked. This may be reflected in the slightly higher bearing metals seen in the 40w column (copper and lead).

I really thought I was going to find a significant deviation from one weight to the other, but these numbers are small enough to be called insignificant. If anything, 30 weights might be showing a tiny edge in performance over the heavier oil. One thing is clear, neither oil significantly lowers Iron wear over the other.

This started off as an attempt to study ZDDP and Oil weight as it effects our 4.0's and strokers. By surveying published UOA's (Used Oil Analysis) from BITOG (BobIsTheOilGuy.com). I started searching there last year and compiled all the UOA's I could find into Excel; that involved strictly the Jeep Inline 6. It took some serious carpal tunnel inducing search marathons to dig up every reference to Jeep inline 6's I could find that involved someone posting their UOA. This involved hundreds of thousands of miles of oil changes (317,778) from a [censored] load of UOA's, spanning 5 years of the BITOG forum (that's as far back as you can search). Included is just about every viscosity of 30w 0W30 on up to 10W30 and 0w40 on up to 15W40.

I threw out any UOA's showing obvious signs of shot bearings. Or new engines that were obviously showing massive break in metals. This comprised at least a dozen or more UOA's showing abnormally high levels of copper and lead. At least two UOA's thrown out due to either a cracked 0331 head or a blown HG (extremely high levels of coolant cantaminating the oil). A few dozen were weeded out due to unintelligible formatting or for lacking all important info like miles on the oil, or viscosity, or exactly what engine the Jeep had. I also didn't use any info from the 4 banger UOA's... they have 2 less cylinders thus their wear metal numbers will be lower. I didn't feel that mutiplying by a 3rd would be accurate.

One bit of errata Mobil 1 (straight Super Syn M1) consistently shows higher levels of Iron than any other Oil... regardless of viscosity. I have two theorys here: straight M1 is a PAO ester based synthetic (as I understand it) esters are extremely good solvents... the esters melt away trapped sludge and grime more so than other oils releasing trapped wear metals. There's some creadence to this, as there are actual expensive Engine treatment systems (AutoRX) that use pure esters to clean out neglected engines. Or #2 M1 also consistently shows lower Phos and Zinc (ZDDP) levels sometimes lower than even current API low ZDDP oils. Which could lead to more valve train wear.

I am a fan of M1, but I use High Mileage which has very good Phos and Zinc levels (old SJ spec) but I am planing on sending out a sample to Blackstone of my current fill (10W40 M1 High Mileage) to see if I don't need to re-evaluate my choosen oil. One thing I'm pretty sure of, I will be going to a 30w next change. Whether it will be M1 High Mileage 10W30 or not is the question. But that's pretty much the only game in town for a high ZDDP off the shelf high quality oil that is also a 30 weight... (oh and not a racing oil)

Maybe that's a different subject entirely but When you've looked at as many UOA's as I needed to to put these numbers together, there's VERY few oils that have zinc and Phosphorus levels above the 10% (1000PPM) target. Even in 2003 there were almost NO oils left that were still in the right ballpark.

No real 20w UOA's were found, and no 15W50 UOA's...

Deisel grade Oils (Delvac and Rottela) did not jump out at me as having better wear numbers. Just as low ZDDP and high ZDDP haven't immediately jumped out at me for better or worse wear numbers. I will have to crunch those numbers, but I expect nothing shocking or particularly enlightening, if only because the 40w's on average have better ZDDP (due almost entirely to the Diesel oils all being 40 weight) but not apparently better wear numbers.

Still At some point I will correlate all these UOA's against ZDDP levels and see if there are any significant trends. Look for that post here later.

 

[jeepman3071]

Nice post KC about the study on jeepstrokers!

As for the 15w40, I don't necessarily think that would lower the iron, especially in the colder climate I live in. The Jeep is usually only used for short trips, and a 15w40 would be very thick on start up. This engine seems to be noisier on heavier weight oils such as 10w40 or even Rotella T6.

The Pennzoil Yellow Bottle seems to run the quietest in this engine so far from the oils I have tried.

As for the leak, it does not leak on the exhaust pipe. It only leaks a slight bit around where the engine bolts to the trans. I also have a small leak from the oil filter adapter. The other gaskets are new. It leaked a lot more when I first bought it.

Thanks for all the comments guys!

 

[salv]

Why not run Pennzoil HM? Thicker in grade, better HTHS, seal conditioners, and the same additive chemistry.
My XJ has run very well on Defy 10w30 and Super HM 10w30. Both have slowed leaks to a minor seep, so there are no more annoying drips in the driveway.

 

[Garak]

Originally Posted By: jeepman3071
It leaked a lot more when I first bought it.

Looks good - a quarter quart over your OCI is absolutely nothing to fret over.

 

[jeepman3071]

It is interesting that the PYB sheered a bit, because the engine seemed even quieter towards the end of the OCI. It seemed noisier with a fresh oil change. By noise, I'm referring to valvetrain noise.

 

[dnewton3]

KCJeep ...

Nice analysis overall. I'd like to see the sigmas and such, and the data a tiny bit thin on total samples, but the overall tale is true.

While "conventional wisdom" is that the 4.0L I-6 wants thicker oil, it's obviously true that the owner is the one who "wants" thicker oil, and the engines really couldn't care less.

I've heard the same thing about diesels for some time. But my personal UOAs show that my use of dino 30 grade HDEO is no better or worse than folks who use synthetic 40 grades, in a statistical sense. And I've got over 500 UOAs in the Dmax engine family to prove it.


Three things have the greatest effects on wear, presuming one partcipates in a decent maintenance plan and does not neglect their equipment:
1) the tribochemical barrier (often manipulated via the OCI)
2) the severity of use (I mean uber-severe; not pulling one's boat on the weekends or sitting in traffic for 20 minutes)
3) equipment design (the simple family lineage of the engine, tranny, etc. Excellent and poor designs are hard to change with lube selection ...)


The 4.0L Jeep engine sheds a bit more Fe than does other engines; no big deal. The same can be said of some other designs (the TDI, the old Chevy 350, etc). That doesn't stop them from running well. The 4.0L I-6 really isn't as grade-preferrential as most folks think, and your data just confirms that. What the engine needs and the driver wants are two totally different things!

 

[Zaedock]

Nice report!

I'm slowly using up my 40 wts in my stash for my Jeep powered rigs, unless I find a really good deal.

My last UOA on 40wts in my trail Jeep was on GTX 10W40 and I managed single digit iron numbers in 1500+/- miles. Considering that it's trail miles with MANY gallons of fuel burned, I thought the results were outstanding.

Still, I had nice results from 5W30 Q-Torquepower and Horsepower (remember those?!?!) and have decided to stick with 5W30 GRP III oils in this rig (2.5L pushing 38x16 tires). Less parasitic drag and great flow to the valve train with a high volume pump.

My rock buggy is going to get a transplanted Cherokee drivetrain (*gulp* an AUTOMATIC – what will I do with my left foot? LOL) and I plan to install my signature HV pump and run a 30 wt year round.

 

[jeepman3071]

I've run a few 10w40 oils in this Jeep along with Rotella T6 and T5. The thicker oils were definitely a bit louder, and the 5w30 gave me a slight advantage in fuel economy. When gas is $4 a gallon, any advantage in fuel economy is a good one.

I have an Amsoil Ea drop-in air filter, a Dynomax Super-Turbo exhaust, and a 62mm bored throttle body. I get 16 mpg around town, and 18-19 highway which I consider pretty good for a vehicle that has a 2" lift, larger tires, and the aerodynamics of a barn.

 

[KCJeep]

Originally Posted By: dnewton3
While "conventional wisdom" is that the 4.0L I-6 wants thicker oil, it's obviously true that the owner is the one who "wants" thicker oil, and the engines really couldn't care less.



Absolutely my conclusion as well. It's not the engine that "likes" heavier oils in the Jeep 4.0, it's the OWNERS!

I don't like too thin in mine either though, I want a kv100 of at least 10.0 and an HTHS of 3.0 at the end of an OCI, but that is still a far cry from any 40 weight. But it means I will start with a "thickish" 30.

Both Jeepman3071 and I have experienced the quietest running engines so far on the relatively thin, slippery PYB 5w30. The Castrol HM I was using was close, but not equal to PYB in that regard.