I would like him to become a member on here and say what he has to say, instead of hiding behind his YouTube videos. It is kind of like that movie the Wizard of Oz! In that movie we had Dorothy, the Tin man, the Lion, and the Scarecrow. It is time for the Wizard to confront the Wicked Witch of the West!
LSJr tests and discusses DexosD babymax oils
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I just don’t know how anyone with as much experience as he has can put any weight into comparing UOAs from a variety of different sue cases. Putting aside the fact that he’s trying to compare wear metals on a UOAs to reach a conclusion, the majority of those UOAs are from different people, we have to assume. Those are all different use cases, towing different amounts, operating in different climates, some with a propensity for short trips and some with a propensity to drive for longer intervals between shutdowns. I could go on, but I don’t think that’s really needed. It does highlight, however, the fact that the trope of “newer engines have tighter clearances and so need a thin oil” needs to die.
I don’t see an issue with his videos. Is the science always perfect? No. It does give a decent representation of the additive packages and base oils contained in the oils he tests which is beneficial for many and is displayed in a manner the lay person can understand.
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He's more than happy to take calls and emails if you want to ask him something. If you contact him, I'd definitely be interested in what he has to say if you could post it.
I contacted him about 6 months ago asking why he’s ranking oils based on UOA wear metals. His response was “because it’s the only data we have”. Obviously that’s not science.
I do enjoy his HPL lab vids. Some good nuggets there.
If so, only because of the presence of excess air (heat sink) at light load, and increased adiabatic expansion of the higher compression ratio. Not typical for all operating conditions. If you were correct, one would not expect diesels to have NOx issues. Instead, we jump through multiple hoops of EGR/SCR/DEF to mitigate NOx production, which is a function of combustion temperature (and presence of excess oxygen).
Diesel combustion chambers are in the piston, and pistons count on oil for cooling.
IIRC, in the LM2/LZ0, typical coolant temperatures are ~210-220F, higher heavily loaded. The very nature of the oil cooler (heat flows from hot thing to cold thing) means the oil will be a few or many degrees higher, depending on load.
The LM2/LZ0 is a particularly warm little engine.
If you had said "generally diesel engines more efficiently extract heat of combustion due to higher compression" then you would be correct. But this has nothing to do with temperatures experienced by the lube oil.
Yes. There’s a reason no official wear studies use UOA data.
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My follow up question to that would be: what other data is there?
There's a few critics of UOAs here, but aside from doing those, what are the options? Hooking up an engine to a dyno and plugging in monitors everywhere you can to track data in real time?
If anything, I would take UOAs on an individual basis rather than a collective average. If someone is using a truck as a lightly driven daily or another using a truck to haul heavy loads, you cant compare those two.
EDIT: I definitely spaced out the taxi cab test. I forgot Amsoil did it with their 0W-20 SS
There’s been several official wear studies posted here over the years. Engines are disassembled and measured. Not one shows a lower viscosity with less wear.
Not many engines maintained correctly wear out. Many more die because of engine/piston cleanliness problems. Ranking solely on wear is ignoring many other factors IMO.
For comparative wear? Several ASTM tests for that, some part of the Sequences. None of them are uncontrolled spectrographic analyses and for good reasons. The problem is the wear differences between oils is small, no fully formulated oil has a problem with wear. Therefore the difference is buried in the noise in a test such as a UOA and cannot be teased out without rigorous mathematical analysis, if at all. It’s just not the test for doing that.
Trying to do what we are discussing here is not just difficult, it is flat out impossible and is bad science. Frankly it’s laughably wrong.
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UOA’s used correctly can help identify problems early. Like seeing an unexpected spike in glycol(coolant in oil). Another member caught a timing chain failing early enough to replace it without damage to the engine. I think of it as what is the engine doing to the oil, not what is the oil is doing to the engine.
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Those temp. are probably close if not the same to the gasoline engines. However, the LM2/LZ0 engine is turbocharged like all modern diesels. So those are pretty normal temps.
It will be more interesting to compare oil temps. In gasoline engines the normal temp. is about 212°F.
Even that’s a bit hokey, it was done more for advertising sake than anything else. The actual standardized tests that measure comparative wear between oils doesn’t take a fleet of taxis and really doesn’t want the uncontrolled environment that they’re being operated in either.
“Real world” tests are often more for show and only as a qualitative affirmation of a controlled laboratory test.
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The babymax generally runs between 250 to 260 degrees
Is that at idle, highway, or towing?
250°F and over would be a challenge for any 0W-20 oil, I guess.
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From this thread: https://www.duramaxforum.com/threads/lm2-engine-oil-temp.1030787/
OP reached 250 degrees and was towing 1500lbs behind his truck. Another user reached 235 just driving.
Our Carnival hits 235 oil temp while on the interstate. Not uncommon for many engines today.
