Mobil 15w50 in 0w20 engine.

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Originally Posted By: Gokhan
My main criticism of "thick-oil people" is that they believe that there is really not an optimal viscosity for wear protection and the engine wear will uniformly decrease when you keep increasing the oil viscosity. They believe that even if you don't notice a difference, margin of protection against wear will always keep increasing with increasing viscosity.


Actually that is the strawman that you continue to bring out...I haven't heard anybody on the board EVER say that increasing viscosity eternally will always improve wear.

Yet, that's the strawman that you've placed against me in various threads, and continue to espouse as in this quote.


Originally Posted By: Gokhan
Any reasonable person knows that too much of a good thing is a bad thing and any engineer knows that there is an optimal range with minimums and maximums for almost any engineering design.


Quick question...

hands up anyone in this thread with an engineering degree and a quarter century in rotating equipment...

*raises hand*
 
"Any reasonable person knows that too much of a good thing is a bad thing and any engineer knows that there is an optimal range with minimums and maximums for almost any engineering design."


Yep, the law of diminishing returns.
 
Originally Posted By: TheKracken
I am still reading more on your post and others in this thread as well as others. Trying to reach a conclusion on thin vs thick still.

It really doesn't have to be a "vs." thing. Despite what we've seen in manuals lately (and even GM manuals from over twenty years ago), an engine can be served by a few viscosity options under several circumstances, and even more options when the circumstances are out at the limits.

GM years ago warned against 10w-40 not because 40 grades were unusable, but because they had issues with the 10w-40 options of the time. Many current vehicles call for a 0w-20 because there are fuel economy benefits, not because they are unable to muster the cranking power to get a 5w-30 flowing at 70 F. The Germans often call for a proprietary, higher HTHS specification because they use very extended OCIs and may face more stressed driving conditions (note that most approved lubes are also winter suitable synthetics, too) because their earlier call for API/ILSAC lubes had some pretty enormous OCIs.

Even leaving CAFE aside and 10w-40 issues of decades ago, there is something to be said for simplicity. There is nothing wrong with trying to eke out a bit of fuel economy (assuming it doesn't cause other major issues). There's nothing wrong with at least attempting to call for a lubricant that will work under almost any condition the motorist will find. Yes, BITOGers generally know that running a 20w-50 in a Saskatchewan winter is foolhardy and a the cold cranking properties of a 0w-XX won't be tested in Arizona. You let the general public run 20w-50 in July, though, and they put 1000 miles on the car, they won't want to change in December, particularly when their manual or OLM indicates they have another 9000 miles to go. Similarly, you let someone get away with the cheapest option for the longest interval, some people will try it. Well, they will anyhow, but if you specify something like a 0w-20, it'll probably be a synthetic, and probably be suitable for a longer OCI, and certainly be okay in the winter.

In that vein, look at what I eventually did with my Audi Turbo 200's service. It had a couple of the issues I addressed above. It allowed everything from a 5w-20 to a 20w-50 to monogrades, depending upon ambient, all with a 12500 km severe service interval on basic API SJ. 15w-40 was the preferred grade over the widest temperatures. Should I have been running 5w-20 in the winter and then running to 15w-40 in spring? Well, I did a bit of 5w-30 in the winter and then ran to 15w-40 in the summer, and then ran into fall again fairly quickly, and that got old pretty quick with only putting 2500 km on the oil. So, I grabbed a 0w-40 A3/B4 or 5w-40 E7, E9 synthetic (not even an option in the manual back then, as I recall) and kept it all year.

The point I'm making isn't that it's necessarily about thick or thin. Follow the manual. If you can't or won't, choose some reasonable range of HTHS, select an appropriate number before the "w" for your climate, an appropriate API or ACEA or builder spec, and run the product year round. If that happens to be a monograde, and that works satisfactorily for you, fine. If it's an A3/B4, fine. If it's a 0w-20 ILSAC oil, that's fine, too.

My Audi would work just fine running a 5w-20 (or a 0w-20) in the winter and a 20w-50 in the summer. I, on the other hand, would stroke out dumping oil at one fifth of the severe service interval just to make sure I can start the car when the ugly weather hits.

There's no real conclusion to reach. You're not going to make your car a Guinness entry for longevity by running 20w-50 or SAE 30 all year, nor will you make yourself immune to winter problems by running a 0w-XX, nor will you slice your gas bills in half by using a 20.
 
Originally Posted By: igs
Originally Posted By: Shannow
Originally Posted By: igs
So which manufacturer was recommending that for their non-hybrid engine?


I was responding to your comment that 0W oils didn't exist at that time...they did...

Manufacturers were specifying 0W oils before Honda BUILT a hybrid...

40 weight is thinner oil????

Sorry, but you are just jumping around and changing your point at every post.

Shannow, fairly addressed your 0W statement and showed that they appeared in the mid 90's before hybrid cars, so you turned it into a 40 grade statement.

I showed a thin oil that was not developed for hybrids but instead for racing (think qualifing oil - to grab pole position) and you turned it into a 0W issue.

Yes I agree that hybrid cars and thin oils are a great match and share some common development. But I disagree that all thin oils were only developed for hybrid cars and that thin oil only exist because of hybrid cars.

But I also don't see that as being a big problem.
 
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Originally Posted By: Gokhan
My main criticism of "thick-oil people" is that they believe that there is really not an optimal viscosity for wear protection and the engine wear will uniformly decrease when you keep increasing the oil viscosity. They believe that even if you don't notice a difference, margin of protection against wear will always keep increasing with increasing viscosity.

Any reasonable person knows that too much of a good thing is a bad thing and any engineer knows that there is an optimal range with minimums and maximums for almost any engineering design.

In fact, there is actually a mass-reported case of thicker oil resulting in more bearing wear than thinner oil. It's the case of BMW M3 engine. Users reported severe bearing wear and bearing failures with the BMW-recommended Castrol 10W-60. The bearing wear was mostly gone when they used the much thinner Mobil 1 0W-40 instead. Oil starvation due to insufficient oil flow because of too small bearing clearances was possibly the reason, but it has never been resolved. Sure, it was a bad bearing design in this case and BMW issued technical bulletins about the bearings that came with too little clearances. Nevertheless, it shows that there is an optimal viscosity range for a given engine and thicker oil does not always result in less wear. Sometimes thicker oil is too thick and it could harm the engine.

BMW M3 engine bearing failures: Castrol 10W-60 vs. Mobil 1 0W-40


Who are "they" i cannot remember anybody saying that they believe that increasing the viscosity of motor oil exponentially increases wear protection.
 
Originally Posted By: SR5

Sorry, but you are just jumping around and changing your point at every post.


It's just Shannow jumping around because he has no argument. Go back and read my original post which got his panties in a bunch. If that still confuses you read the title of this thread. I'm going to stop replying to his off topic posts.
 
Originally Posted By: igs
It's just Shannow jumping around because he has no argument. Go back and read my original post which got his panties in a bunch. If that still confuses you read the title of this thread. I'm going to stop replying to his off topic posts.


OK, in order...
You stated that Honda were the first to spec thin oils (I take it that you mean 20s, the topic of the thread)..they weren't..
You then stated that 0W didn't exist before the Insight...they did...

What's your problem ?

Who were you in one of your last incarnations ???


Edit...excerpt is from the maintenance manual for the 1969 Chev Engined Holden Kingswoods...
 
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Little bump to an older thread for those of you who are still stuck at home and need some entertainment, and maybe even some knowledge may be found between the lines.





P.S. Dear mods, please ease off on locking every thread that's been inactive for some time. Or provide valid points on what is being violated in the thread, other than just another form of "Nuff said".
 
Oh i remember this thread, it was fun but interesting too.

And i thought i was a radical putting 20W-50 in an engine spec'd for 10W-40 a few times.

I have never bought an oil thinner than 10W-40 in fact, not that i can remember lol, never bought a full synthetic either i think.
 
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Vladiator - I refer you to this: https://www.bobistheoilguy.com/forum-rules/ as well as this: https://www.bobistheoilguy.com/foru...26/bitog-standard-of-conduct#Post5289126

In which the moderators have discretion on what is acceptable.

What is not acceptable - personal conflict, trolling, baiting, doxing, etc. and the determination of what constitutes that is, again, up to the discretion of the moderators.

Those points are valid. This thread provides no new information but it does have conflict and the only reason to bump it is to re-live the conflict.

This thread is locked.
 
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