Kendall is a good oil. I used the conventional 15w40 in an N-14 that went for 1.4 million without a major issue and still only used a gallon every 8000 miles and got 7 mpg avg when I gave it up.

Both the syn and conventional version of Delo have given me very good numbers. Just that there was no advantage to be seen in using the synthetic version. So went back to the conventional. $7 a gallon difference is substantial. Maybe there is something to Chevron's claim that their ISOSYN technology in their conventional 400 LE 15w40 rivals the performance of full synthetics and is not just marketing hype.

 

I am confused here, why would you run a gallon of Lucas in a virtually new engine or newly rebuilt one? Is there something lacking in modern engine oils that they need to be "stabilized" by Lucas? And what is in LOS? According to those that have done virgin oil sample analysis on it, nothing more than a 50w base oil with no beneficial additives. In other words, nothing more than the old STP Oil Treatment in a gallon jug. Why not just use a 15w50 engine oil will all the beneficial additives in it and a gallon of that is half that price of LOS.

We all are victims of marketing gurus now and again. For some strange reason, we all seem to know more than the guys who actually make and test engine oils, and we seem to think that their products are sub standard and need some help from another company that is playing on this mindset and marketing to us something we really have no statistical proof we need. Talk about a circular reasoning. And God forbid, that we should actually take the advice of those who design, build, and test their engines when they say in their operation manual that the owner should not use engine oil additives. Silly OEM's. Forrest Lucas and Mr. MotorKote know more than they do! And just because our engine did not have a catastrophic failure when we were using the additive, does not prove that the additive prevented a catastrophic failure. You cannot prove a negative.

While some of these things like Lucas, MotorKote, etc may not cause a problem, there is no detailed industry standard testing done by a objective group on a series of engines using blind study techniques that show these additives provide any longevity and reduced wear. Wonder why none of these products pay to have a study done by a third party group, like the Technology and Maintenance Council, to really pad their marketing? But boy, brand loyalty is really something. The "we have used X.Y.Z. additive since our family moved west in conestoga wagons and it has always worked for us" does not a definitive study make.

 

I'm confused why so many of you have stated that you change your oil every "x" number of miles, pull an oil sample and it looks great. Wouldn't it make more sense to pull the oil sample and only change it if the sample indicated that the oil was fading?

I've got an '06 ISX (currently 525 HP / 1750 ft*lbs) EGR Deleted with 917k miles. I've tried Rotella, Delvac, Valvoline Premium Blue Extreme Synthetic, and have finally settled on the 15W40 house blend that my oil supply company uses in its own trucks. To be fair to Rotella and Delvac, I only used those oils before doing the EGR delete so I can't make an honest head to head comparison with Rotella and Delvac and what I'm using now. With the Valvoline Synthetic, I was able to routinely go between 60k and 70k miles (changing the oil filter every 15k miles) before TBN dropped to close to the "3" range. With the house blend I've finally settled on, I'm getting around 45k miles before TBN drops to around "3" (changing oil filter every 15k miles). Oil consumption with the house blend is about the same with the Valvoline Synthetic (about a gallon every 15k miles). The reason I've decided to stick with the house blend is that while I'm not able to run it as long, I'm seeing much less wear metals in my samples (adjusted for mileage differences) than I was with the Valvoline. Additionally, I was paying close to $1300 for a 55 gallon drum of the Valvoline, and a 55 gallon drum of the house blend sets me back a whopping $432.

 

Can't say for everybody, but here i go.... Oil is cheap, better safe than sorry, i'm an old school....You are probably correct, but it makes me feel better..!

 

I understand where you're coming from and it is impossible to go wrong using your school of thought. I imagine that you pretty much can speak for all the folks who change at a pre set interval. My feeling is that oil is cheap, but oil analysis is even cheaper. My oil analysis, done by a Valvoline Lab, only runs $7 per sample. I figure that if I pull a sample and it looks great, I'm being wasteful if I change my oil. Doing my own services, tires and basic repairs has allowed me to have a maintenance cost of $.072 per mile over the last 755k miles (that's for truck & trailer (including tires) and APU). A quick look at my numbers tells me that if I'd changed my oil and filters every 15k miles, even doing the work myself, it'd have added up to about $3,200 extra out of my pocket. If I'd paid Speedco to do the work like many owner operators do, the cost would have been roughly an additional $5k out of pocket. I know that $5k over five years isn't a huge amount of money, but it does all add up.

I'm not picking on you or anyone else for being a traditionalist when it comes to performing maintenance, just pointing out that there's more than one good way to do things. It's all personal preference and where you comfort zone is, I guess.

 

Agreed!

 

I too have a 2006 ISX. Even though the factory fill was Delo, the engine didn't seem to care for it. Ditto for Rotella. I ran Delvac for awhile then switched to Mobil Synthetic; both were fine. A couple of years ago, I switched to Valvoline synthetic and it has performed well. Samples are always good and I still don't burn a drop. I usually change between 25,000 and 35,000 miles. Could the oil go further? Sure, but unless you put two trucks side-by-side being driven the same way with one running extended intervals and one not, you don't know for certain the impact on component life. Sure the additive levels are above the threshold, but is there really no difference in the protection given by an oil with its additives depleted by 70% as compared to oil that has only been depleted by 50%? Like Solo said, oil is cheap and in the absence of a definitive study, I prefer to take a more conservative approach. For me, I only change the oil about 4 times a year so it's not much of a burden.

 

I think the answer to that is in the wear metal numbers. That pretty much is the whole point of oil, right? To minimize the amount of friction and therefore the amount of metal that wears from the various internal components? It's obvious how well the oil is doing its job by the amount of wear metal present in a given sample. I pay attention mostly to TBN, soot, and viscosity to tell me when the oil is approaching the point where I'd want to change it. When TBN gets around 4, I plan on changing the oil the next time I'm home (I don't run more than 15k at a time anymore). Soot has not been a problem since I deleted my EGR, and viscosity was only something that would start becoming an issue when I ran the Valvoline synthetic and I'd go as much as 75k miles on the oil.

I’m curious how your wear numbers compare between the Valvoline synthetic and other oils you’ve used. With the house blend 15W40 I’m using my wear numbers are the same or a little better than they were with the Valvoline, Rotella or Delvac.

 

Wear metals don't always paint a complete picture. Our engines are a perfect example. The ISX is well known for having cam issues. Several people that I know have had the problem said that there was never an indication in their samples of an impending problem. Some of the labs have also acknowledged that oil analysis cannot catch everything and cite this particular problem as an example. The cause of the failure is debatable, though it IS caused by poor lubrication. Cummins blames it on extended oil drains. Personally, I think that's a cop-out and the problem is a result of faulty design and/or parts. Still, my point is that oil analysis does not seem to do a good job of highlighting the problem. Bottom line though, like you guys said, it comes down to personal preference as to how long you want to go between drains. If TMC came out with a recommendation based on empirical third-party testing that said go ahead and run your oil until certain attributes drop to such-and-such a number, then I might be inclined to change my procedures.

As for my own wear metal numbers with various oils, I'd have to go back and look. I've never had a problem with any of the oils in terms of wear metals. Some oils depleted their base faster, one actually burned away, and the engine just didn't run as well on some. However, I have gone from stock to EGR disabled to EGR deleted, so that has put progressively less stress on the oils.

 

Same here.