Jeep 4.0L - PYB 10w-30 (first UOA)

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Did my first UOA on my 2000 Jeep Cherokee. It's got 99,500 miles on it (original owner!). I've been running PYB for the last few years, changing the oil every 6 months. My OCIs are usually in the 3,000 mile range, including this one. Jeep gets a good mix of driving. I'm really pleased with the results, particularly the iron number.

"Wear metals look great in this first sample from your Jeep. Universal averages show typical wear after about 4,100 miles on the oil. This oil saw 3,000 miles, and wear is lower. Much lower, actually, showing some excellent wear characteristics here. No contamination was found in the form of fuel, moisture, or coolant and while the viscosity was just a little low, that's not a serious concern since fuel wasn't to blame. Air and oil filtration look good. We're impressed by how good this engine looks! We'll look for more of the same next time. Nice report!"

Result / Average

Aluminum 3/4
Chromium 0/1
Iron 8/27
Copper 1/4
Lead 0/3
Tin 1/1
Moly 273/71
Nickel 0/1
Manganese 0/1
Silver 0/0
Titanium 0/0
Potassium 2/3
Boron 83/46
Silicon 10/12
Sodium 4/42
Calcium 2408/2064
Magnesium 8/140
Zinc 917/872
Barium 0/0
Phosphorus 759/730

Sus Vis @ 210 55.7 / 59-68
Cst vis @ 100 10.16 / 9.9-12.7
Flash 405 / >365
Fuel Antifreeze 0
Water 0
Insolubles 0.2
 
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Nice! What weight do you run? I have a few UOAs with PYB for my 2000 Cherokee 4.0 and so far PYB 10w30 has yielded the best numbers. Mine also had single digit iron wear.
 
Originally Posted By: barkingspider
Looks like your preventative maintenance scheduled worked perfect. Cool, broh

Thanks, brah



Originally Posted By: jeepman3071
Nice! What weight do you run? I have a few UOAs with PYB for my 2000 Cherokee 4.0 and so far PYB 10w30 has yielded the best numbers. Mine also had single digit iron wear.


I run 10w-30. I've seen your UOAs so I was expecting (hoping) for similar results! The real reason for doing the UOA was to ensure that no coolant was getting in the oil - thank you 0331 head. It's not losing coolant or anything, just want to be proactive.
 
Another great PYB Jeep 4.0 UOA, thanks for posting! Was this the High Mileage or regular Yellow Bottle?
 
Nice UOA.

So - what did you learn from this? Any chance you'll extend the OCI? Could EASILY 2x it out to 6k miles once a year. Probably even 3x it out to 9k miles.

Yes, heresy; I know. But hey - why let facts and data get in the way of good ol' fashioned rhetoric and mythology?
grin.gif
 
Originally Posted By: dnewton3
Nice UOA.

So - what did you learn from this? Any chance you'll extend the OCI? Could EASILY 2x it out to 6k miles once a year. Probably even 3x it out to 9k miles.

Yes, heresy; I know. But hey - why let facts and data get in the way of good ol' fashioned rhetoric and mythology?
grin.gif



6,000 miles is doable, but I wouldn't go 9,000 miles on conventional oil in this particular engine. I've seen plenty of sludged up 4.0s, and my own engine is pretty dirty inside from previous owner neglect.
 
Originally Posted By: KCJeep
Another great PYB Jeep 4.0 UOA, thanks for posting! Was this the High Mileage or regular Yellow Bottle?


Thank you! It's just regular yellow bottle. And like you've alluded to in other posts, my 4.0 definitely runs quieter on PYB as opposed to others.

Originally Posted By: jeepman3071
6,000 miles is doable, but I wouldn't go 9,000 miles on conventional oil in this particular engine. I've seen plenty of sludged up 4.0s, and my own engine is pretty dirty inside from previous owner neglect.


I'm going to keep my OCI schedule the same. The only modification I might make is changing the filter annually (every other OCI) instead of bi-annually. I'm trying out a massive Baldwin B7311-MPG for the first time - it has great flow properties, outstanding filtration, and ridiculous capacity. Given that the Jeep holds 7.0L of oil (with the bigger filter) and that this UOA was solid, I'm confident that the bit of oil that doesn't get drained (kept in the filter) won't be a problem.

I will mention that with the Baldwin filter, my oil pressure is slightly higher and pressure builds quicker at start-up (check gauges light no longer flashes for an instant). I had previously used Wix, Mobil1, or K&N filters. Here's more info on it, beginning on post 24: http://www.ihpartsamerica.com/forums/bas...-filters-2.html
 
Originally Posted By: jeepman3071
Originally Posted By: dnewton3
Nice UOA.

So - what did you learn from this? Any chance you'll extend the OCI? Could EASILY 2x it out to 6k miles once a year. Probably even 3x it out to 9k miles.

Yes, heresy; I know. But hey - why let facts and data get in the way of good ol' fashioned rhetoric and mythology?
grin.gif



6,000 miles is doable, but I wouldn't go 9,000 miles on conventional oil in this particular engine. I've seen plenty of sludged up 4.0s, and my own engine is pretty dirty inside from previous owner neglect.



Your insols are .2; hardly heading towards sludgeville ...

Right thing to do is to extend, but smartly and not blindly. Run this OCI out 6k miles and then UOA as well as pop the cover off and take a picture. If things are good, perhaps 7.5k miles next, then 9k. I would NEVER advocate a blind run towards 3x the OCI. But nothing wrong with using the data you pay for to make smart decisions.
 
With all the guys now running PYB in the Jeep 4.0, Blackstones "average" wear numbers are going to be going down!
grin2.gif
That iron number especially is crazy low for a Jeep 4.0.

I don't see a TBN. The 4.0 can be kinda rough on TBN retention especially if short tripped. I'd suggest extending to 5k next, do another UOA and get a TBN that time around to better evaluate your top end for this oil, your engine and your use pattern.
 
Originally Posted By: DoubleWasp
Making me think I might want to look into a new oil.


I haven't pulled a UOA on my 4.0 (too afraid) but I did gain some gas mileage by going from RT6 to pennzoil conventional.
 
I haven't seen enough of these yet to prove it, but thus far I have noticed a trend that the very best UOA's for the Jeep 4.0 when using PYB have come from those that have used it consistently for a while.

I don't plan to give mine anything else ever again, so future UOA's could be interesting indeed.
 
Originally Posted By: KCJeep
I don't plan to give mine anything else ever again, so future UOA's could be interesting indeed.


I'm with you there. PYB 10w-30 is all this Jeep will ever see again. Although we'll have no way of knowing, I'm really curious as to why the 4.0L likes PYB.
 
Originally Posted By: jls095
I'm really curious as to why the 4.0L likes PYB.


Same here.

Heck, its one of the most reasonably priced name brand conventionals at WM. I'm not complaining.
smile.gif
 
I think it is the sky high moly content of PYB that does the trick, but we will likely never know for sure. All I know is, it works!
 
Originally Posted By: KCJeep
I haven't seen enough of these yet to prove it, but thus far I have noticed a trend that the very best UOA's for the Jeep 4.0 when using PYB have come from those that have used it consistently for a while.

I don't plan to give mine anything else ever again, so future UOA's could be interesting indeed.


I'm going to try for straight 10w-30 this spring! Not a mix of 5w-30, 10w-30 and SAE30
 
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