And let people endlessly continue to make unwarranted conclusions based on suspect data? And post them here? No thanks.
Video - Engineering Explained, Do Thin Oils Destroy Engines?
- Thread starter martinq
- Start date
This is somewhat taken out of context of the video. Check timestamp 17:45- . While iron and aluminum didn't increase, he did say their testing showed lower viscosity oils had an impact on connecting rod bearings, which is the failure mechanism of GM's L87 engines.
Last edited:
Bingo!
Your oil viscosity is either "enough" (no added benefit from higher viscosity) or "not enough" (excess wear). If your testing shows bearing wear then something probably needs to be "fixed".
Generally speaking, off-the-record hearsay evidence isn’t admissible in court.
That is such a fallacy. If Corporation X just makes a product that is unreliable cost way too much money. But corporation Y makes a similar product that is better more reliable and cost the same. People go to corporation Y and X goes into the dust bin of history. Also most companies will stand behind their product it’s good for business.
That could also be from hey let’s put this after market oil additive into the engine because some nascar diver said it’s good. Yet it’s causing chemical reactions and increased wear.
Who said anything about aftermarket oil additives in this thread or in the video?
Nobody but that is something that can cause problems in the motor. And people use them thinking it would help but may harm it.
Even if the viscosity is "just enough" to give adequate bearing MOFT most of the time, it can be better than "just enough" by going up a grade (or two depending on what was originally speced and what the more severe use conditions are) to give more wear protection headroom - that's the added benefit. Running very near or right at the bottom of the hydrodynamic realm on the Stribeck Curve isn't what I'd call "ideal" to ensure optimum engine wear protection.
EE basically shows that's the case with his Stribeck Curve example, and getting added film thickness and more protecting is also the case with parts in the mix lubrication realm. He eludes to the slight negatives of more viscosity, but doesn't clearly point out the benefits of having more oil film thickness. That was the move GM made on the engines inspected for the recall, and if not found to require an engine replacement it got 0W-40. GM as well as all engine designers know bearings have more protection with thicker oil.
Last edited:
Thickened from vaporization (Noack factor) from being ran too long.
What is the explanation for why GM recommends 0W20 in replacement engines ?
Why would they seek avoiding CAFE penalties when warranty engine replacement is exponentially costlier ?
EE stated that specifically designed additive packages make thin oil effective without viscosity.
As far as bearings go, I kept looking and looking for copper in my UOAs, but it wasn't there to be found.
As always, know your engine and driving conditions.
Why would they seek avoiding CAFE penalties when warranty engine replacement is exponentially costlier ?
EE stated that specifically designed additive packages make thin oil effective without viscosity.
As far as bearings go, I kept looking and looking for copper in my UOAs, but it wasn't there to be found.
As always, know your engine and driving conditions.
OVERKILL
$100 Site Donor 2021
The replacement engines won't have the mechanical issue present in the defective engines, so they should be fine on 0W-20.
Yes.
But EE made this comment in the context of "justifying" thin oil.
Don't dispersents help with such things as tiny dense soot with timing chain protection per SP/GF-6 testing requirements ?
I would never tow a boat or trailer with 0W20 though.
Maybe these GM engines should be using stout yet relatively thin oil.
I am thinking of HPL's offerings.
--OVERKILL 0W20.
--wwillson's beefy 5W20.
--RDY4WAR's 10W20.
Of course thicker must be on the table.
M1 0W40 or ESPs.
AMSOIL's 0W30 SS.
I am thinking of HPL's offerings.
--OVERKILL 0W20.
--wwillson's beefy 5W20.
--RDY4WAR's 10W20.
Of course thicker must be on the table.
M1 0W40 or ESPs.
AMSOIL's 0W30 SS.
OVERKILL
$100 Site Donor 2021
The word "effective" is doing a lot of work there. MOFT is still the driving factor in areas that are hydrodynamic. While coatings and additives can help control wear in areas that are mixed/boundary, they do not eliminate it. Additives do not allow you to transition journal bearings from hydrodynamic to mixed/boundary; they do not "replace" viscosity in the hydrodynamic regime.
My recollection of the Honda paper that @Shannow posted years back, was that as you get into the mixed regime, friction is reduced on the Stribeck curve, before going back up:
So, despite having some form of contact (and subsequently wear), this was the "sweet spot" for friction reduction, and thus, fuel economy.
The idea then, was to control wear; have "acceptable" wear, with more components operating in this regime, to improve fuel economy, and this was enabled by special coatings and additional FM additives in engine oil, allowing the use of thinner grades like 0W-16, 0W-12 and 0W-8, which were key to getting those components to operate in this space.
xW-20 and an HTHS of 2.6cP is right on the bottom of where "traditional" designs still work properly. As long as you can keep oil temperature under control, and you don't experience huge amounts of fuel dilution (or shear), then it is safe, as evidenced by the HEMI and the Ford Modular engines. However, as we also saw with the Coyote, which has higher power density than its Modular predecessor, that oil temperature parameter is critical in maintaining MOFT, which is why Mustangs were neutering themselves on the track when the oil temperatures got out of the acceptable range for the grade.
I ain't no kinda expert, but I do subscribe to frequent services with quality parts. In sunny northern CA, I am not sure there is that much difference between 0w20 or 5w30 in certain scenarios. I use 5w30 HM in high mileage engines like the Hondas I service. Do they go through less oil between services? Maybe? Placebo effect? Dunno.
Kinda funny... The 3 Acura TSXs I service (2 2007 and 1 2006) spec 5w30 for the mighty K24. I believe the K24 in the Accords spec 5w20... Go figure.
All good. 5K OCIs for the win!
Kinda funny... The 3 Acura TSXs I service (2 2007 and 1 2006) spec 5w30 for the mighty K24. I believe the K24 in the Accords spec 5w20... Go figure.
All good. 5K OCIs for the win!
I did notice that Toyota "backed off" and spec'd 0W20 on Corolla GR, high output 3 cylinder.
I see temperature control as the big factor...and quality control in design and manufacturing lol.
BTW cudda swore EE said something like "increasing viscosity did not improve protection" or similar...law of diminishishing returns CAN work both ways, I guess.
Thank you OVERKILL, et al.. The high end commentary is always appreciated as an opportunity at rapidly learning details.
I just kicked down $35 for a book "Third Edition Lubricant Additives Chemistry and Applications" 2022 Edited by Leslie R. Rudnick.
Lordy there is a lot to digest there.
EE is basically saying if you have enough protection, then you don't need any more. But here's the clincher ... how do you know you always have enough MOFT protection in all driving conditions? Only way to really know is do your own test program or trust the "recommended" viscosity call-out in the OM. And as shown here many times, the same exact engines used in other countries show a whole range of acceptable viscosity above the lowest "recommended" called out. In fact, some of those OMs show that anything from 0W-20 to 20W-50 could be used depending on ambient temperatures. So engines are not "designed for" any specific viscosity, expect those that spec 0W-8 and 0W-16 as has been discussed in many threads. Instead, engines are designed to be able to use a whole range of oil viscosity.
Many studies show that more viscosity results in less wear overall, more so in some engine components than others. Most of the wear studies show that as the HTHS starts going below 2.5-2.6 cP, the wear starts increasing more in certain engine components. Yes, in most cases the "recommended" viscosity is going to work for everyday street driving. @OVERKILL mentioned "xW-20 and an HTHS of 2.6 cP is right on the bottom of where "traditional" designs still work properly", which is why engines had to start using special design features to start using oils below xW-20. But is xW-20 always going to give the same wear protection as a thicker oil? I say not always, and the example of Ford now deciding to finally go up from 5W-20 to 5W-30 in the Coyote is a good example. They only did that for one reason, that's to give more engine protection. The Coyote always got 5W-30 specified in other non-CAFE countries, but Ford decided to go with 5W-20 in the USA.
My take is if the engine specs xW-20 or less, go up a grade to add some more wear protection headroom. If the vehicle specs a xW-30 the only time you might go up a grade if it's going to be used for track use, or some other very heavy use conditions.
Here's what happens on the Stribeck Curve if you go up in viscosity. The MOFT is increased in both mixed and hydrodynamic lubrication, and that means more parts separation and less wear.. The friction in mixed lubrication could actually go down, which helps offset any increase in oil shearing friction in fully hydrodynamic lubrication. What EE didn't really clarify very well is that going up in viscosity adds wear protection because it results in more MOFT between moving parts. That's the whole role of viscosity, to keep parts from rubbing and wearing. Nothing bad happens when there is some added MOFT, regardless if it slightly reduces the fuel economy.
Seems the GM recall has been going through some updates, but if not mistaken it sounds like the engines on the road and currently sitting on dealership lots get 0W-40 (if the engine isn't replaced), and it's to be then specified and used for the life of the truck. Sounds like only new engines produced beyond the recalled engines will still be getting 0W-20. Watch GM finally wake up and bump it up new engines to 5W-30 like Ford did with the Coyote, lol.
Last edited:
Similar threads
- Locked
- Locked
