The basic oil analysis at Blackstone is $25. This tells you how your engine is wearing, whether there's water or coolant in the oil, etc.

The TBN test is an additional $10. This is the test to determine how much additive is left in the oil. You want this test if you're trying to safely stretch the distance driven between oil changes or just want to know how the oil is performing.

When I first started using Blackstone, I paid the full $35 to get the basic analysis and the TBN test on the first oil sample to see how the oil was doing. After that I just paid $25 for the basic test, because the TBN wasn't telling me anything new. If I were to change oil brand or buy a car that used a different oil, I would get a TBN. I'm still on my first regular fill of the Joe Gibbs oil in my stroker, so I will likely get a TBN on it when I get my first oil analysis and drop it after that.

 

Cool. Learned something new. Thanks. That's what ill be getting

 

I just drained out my spring fill of T5 and replaced it with a fall fill of T6. Didn't drive the Jeep that much over the summer, so the mileage is kinda low, but 10w is too heavy for winter here. Have a sample that I have to send off this afternoon.

 

Great discussion here.
This is an excellent write up, Salad did a fantastic job.
No disrespect to Salad, but I have just a little bit different conclusion to his presentation.

I have read this thread, studied it, and read many of the references and other 'Oil' threads. I have been a 40+year user of Mobil 1 and after reading this thread, I changed most of my driven cars, 3 Jeep XJs and Ford Taurus, all with 150,000 to 200,000 miles, over to Rotella T6. Yes I use Rotella T6.

I am only looking at 2 oils, Mobil 1 5w30 and Rotella T6 5w40, as they are the only oils I would consider and have used.

I am now revisiting that decision and will be changing back to Mobil 1.
Why?
When comparing these 2 oils, Rotella T6 5w40 and Mobil 1 5w30, here is what I am looking at-
Mobil 1 5w30 105,875psi, Zn=801, Phos=842, Moly=112, Ca=799, TBN=7.5
Rotella T6 5w40 67,804psi, Zn=1264, Phos=1147, Moly=59, Ca=1066, Mg=1187, Boron=69, TBN=10.6

Measured Wear Prevention- this is a biggie for me. The higher the psi, the more wear protection and less engine and bearing wear. Big win for Mobil 1.
Zn/Phos- need an average amount, not excessive. Draw, + to Mobil 1 for lower Phos and + to Rotella T6 for higher Zn.
Moly- more is better, offsets the lower Zn. Allows for lower Phos and saves the cat converters. Win for Mobil 1 x2 on both accounts.
Ca- detergent, cleans the crud and sludge, also cleans off Zn, In a new, rebuild or well maintained vehicle, there is little to no sludge to clean off and only need an average amount of Ca. Draw, Win for Rotella T6 for use in heavily sludged engines, Lose for Rotella T6 for cleaning off Zn
Boron- I can't find data on Mobil 1 content. Kudos to Rotella T6 for using it to add/aid in wear protection but it's total package of Zn, Moly and Boron (67,804psi) do not add up to the wear protection of Mobil 1 (105,875psi).
TBN- alkalinity to combat combustion acids and for longer oil life. Win for Rotella T6 for longer alkalinity reserve and potentially longer oil usage. Average value, Mobil 1, will support 5000 mile or more oil changes.

It is the 'whole package' of the oil that is important.

For me, with my 3 high mileage Jeep XJ 4.0s and Ford Taurus 3.0, Mobil 1 is the most ideal oil to run.

And Yes, Rotella T6 has a place in it's use in the Jeep 4.0L or high mileage commuter car. Whatever oil you are currently running, I would change the oil and filter and use Rotella T6 for one oil change and one oil change only. Let it's strong detergent/cleaning package, clean up your engine's sludge and grime. Then switch to Mobil 1 5w30.

Tomatos, Tomatoes.
Now get out there and enjoy your XJ and do some wheeling!!

 

What are your thoughts regarding the common occurrence of Mobil 1 oils returning high iron wear numbers in their UOA's for the 4.0?

 

Don't know about that. Where is this happening? Isn't iron levels more related and proportional to interval time?

 

Its common knowledge over at Bobistheoilguy that Mobil 1 has abnormally high iron content in the Jeep 4.0 oil analysis. A quick google search brought up the following threads:

http://www.bobistheoilguy.com/forums...pics/2706595/1

http://www.bobistheoilguy.com/forums...&Number=252278

http://www.bobistheoilguy.com/forums...&Number=217871

http://www.bobistheoilguy.com/forums...opics/245384/1

http://www.bobistheoilguy.com/forums...01#Post2246601

http://www.bobistheoilguy.com/forums...Number=2289686

 

A few pages back we discussed the pressure-until-failure/wear scar result. The results are interesting but raise far more questions than offers answers. I find the conclusion that extremely cheap conventional PCMOs are able to provide better engine protection than synthetic HDEOs without ANY explanation extremely odd. A hard-working 15L 21:1 diesel with 40psi boost and DPF is throwing a LOT more punishment at the oil than a 2L 9:1 NA gasser... The whole thing is called into question. The "test results" - even if accurate - are FAR from a complete picture of the role performed by engine oil. Proper test results taken with, say, ASTM D7755, would be interesting to see, but in the mean time classifications and actual data from a reliable source is the only thing we can really trust.

What Bocefus found is EXACTLY what I ran into when researching this thread. It is very strange. What throws a wrench into our armchair oil scientist discussion are other additives and the quality of the base oil in the first place! There are apparently certain AW additives that are a chain of synthetic polymers - obviously these will not show up in a spectral analysis. This further underlines the point that UOAs are really the definitive guide to interpreting the performance of a given oil.


Not necessarily. Particularly within the context of this thread, which explores the reasoning behind using an HDEO in a gasoline engine, a lower W rating is very important. Within this context of HDEOs we basically have 0w40, 5w40, and 15w40. 15w40 is, without question, too thick for year-round operation in a 4.0L in MANY areas of the planet, and one could say for the majority of English-speaking Jeep owners. In the desert and mountains of southern North America it absolutely gets cold enough to warrant a low W number. Additionally, a lower W rating will provide better fuel economy until the engine is warmed up.



Indeed, most oils of today do. This is more to illustrate that a 20-weight oil with low HTHS would not be appropriate without careful examination and testing.



I addressed the "extra" phosphorous concern earlier one, but I feel your pain. Nobody likes to pay extra parts if it can be avoided!


Agreed. HOWEVER, we're talking about 4.0Ls here. On CherokeeForum I think we probably have a dozen or so engines that were actually maintained properly since they were new.

I will also elaborate that, when we start talking about HDEO and synthetic lubricants, part of the goal is usually to extend oil change intervals. I think detergents and dispersants play an important part in keeping the engine clean long enough to delay wear and prevent deposits from forming. The reality is that most oil filters aren't fine enough to catch all the crap flying around - our beloved WIX cellulose filters are only about 25 microns nominal - so I consider extra deposit-fighting power an asset. Higher levels of ZDDP can also help in a higher detergent situation where the protective coating might otherwise be totally stripped.

Glad you liked the read!

 

thanks for clarifying that.... that's exactly what I was referring to ....

 

Wow that's quite the read, lots of good info for me.

I just did a oil change with M1-301 xl filter and 15w 40 rotella.

Getting a lifter tick and lower end knock since the change. No noise before.

I will drain and fill tomorrow with a 10w 40 synthetic and see if that gets better.

 

It looks like the 4.0L has high Iron regardless of which oil used. All those threads on 'Bob's site' and I am not convinced that it is the Mobil 1 that was the culprit. Sounds like first oil change using Mobil 1 and bad, well worn out engines with leaking injectors and dirty, poor filtering air cleaners. Whatever the reason, I will keep an eye out for Iron from the Mobil 1. Thanks for the heads up.

Extended OCI, is that like 5,000 to 10,000 miles or even more miles between oil changes?

 

"Bob" is quite the site. Makes you a little paranoid reading about iron in oil and and torn filter elements. I learned a lot over there, but have finally just gone back to basically changing my oil ever 6 months(4000) miles in my 87. We've all read about 4.0's that have gone 400k miles with whatever oil was on sale. Mobil or Rotella are great oils and you have nothing to worry about.

By "extended", I think of extending past the factory max mileage of 7500 miles in non- severe conditions. With an oil change done by me costing less than $20, why bother to try and extend it? Plus I enjoy changing the oil, and it gets me under the Jeep to look around.

 

Yeah I'm the same way. I wont change it with less than 3000 on it but it cost so little why not change it every 3k-5k? I use a vehicle lift to change mine and use the time while it's draining to take a gander at stuff underneath that I don't normally get to see while it's on the ground.

 

I've read a good bit of this thread and am considering switching from my current fill of 10w-30 Castrol GTX to 5w-40 Rotella T6. However, I have two questions before I commit.

First, will there be any noticeable difference in mileage, performance, or otherwise from running a heavier 40-weight oil at operating temps?

Second, I have a '98 with 130k on it. Should I have any concerns about leaks from switching to synthetic at this stage in the game? I've recently replaced the oil filter adapter o-rings and the valve cover gasket, so it doesn't leak much as it it. Perhaps one drop every couple of days, if that. I've run Mobil 1 synth in my VW since new with zero leaks, but that's a different situation.

 

I just switched to T6 on my last oil change. I did notice a slight increase in mileage I have not noticed any oil leaks at all since the change. Right now i have 266,000 on my jeep. As far as I know it was always run on 10-30 conventional its whole life. I only started running Diesel oil in it after reading this right up Salad did. The only way to find out if it is going to leak with the change over is to change it and see. But if you did the o-rings and the cover gasket you should be in a good spot to change it.