Engines that actually require Thick or Thin oil?

[Yah-Tah-Hey]

Originally Posted By: Shannow
You've been here 4 years...what have you absorbed from what you've read ?

Use your owner's manual in the market in which it is intended, for the typical usage pattern within that market, and you negate both of the bookend examples that you've stated.
Ah yes, "use your owner's manual." Or a variation, "follow the written maintenance instructions and procedures attached." Story of my thirty something year career in power generation. Never succeeded in selling that idea to upper management. I can't remember the number of times equipment failed and the dollar amount we lost because some yahoo had the written instructions right there on the work order and never bothered to open the package until he/she went to sign off on it.And NO ONE was held accountable.

 

[ZeeOSix]

Originally Posted By: walterjay
My SantaFe owners manual says I can run 5-20 or 20-50 depending on the temperature. I always use 5-30


KIA has some common sense, doesn't care about the "CAFE Police".

 

[andyd]

As a driver of heaps most of my life, this is why 0w20 scares me As a car wears, stuff happens. A coolant temp sensor getts wonky and reads low. An O2 reads lean and the brain dumps fuel. All kinds of things that make the engine work harder and hotter. How much fuel does it take to thin 0w20 to a dangerous point? I don't know, but I would say that 20w50 will take more fuel before it gets dangerous. If I'm wrong about this please school me.

 

[ZeeOSix]

Originally Posted By: andyd
As a driver of heaps most of my life, this is why 0w20 scares me As a car wears, stuff happens. A coolant temp sensor getts wonky and reads low. An O2 reads lean and the brain dumps fuel. All kinds of things that make the engine work harder and hotter. How much fuel does it take to thin 0w20 to a dangerous point? I don't know, but I would say that 20w50 will take more fuel before it gets dangerous. If I'm wrong about this please school me.


And all these new cars using xW-20 (and some with xW-16) with DI engines which dilutes the oil some, and the manufactures calling for longer and longer OCIs, seems there is a bunch of stuff adding up in the wrong direction.

 

[PimTac]

Originally Posted By: andyd
As a driver of heaps most of my life, this is why 0w20 scares me As a car wears, stuff happens. A coolant temp sensor getts wonky and reads low. An O2 reads lean and the brain dumps fuel. All kinds of things that make the engine work harder and hotter. How much fuel does it take to thin 0w20 to a dangerous point? I don't know, but I would say that 20w50 will take more fuel before it gets dangerous. If I'm wrong about this please school me.




If it scares you that much, why are you still running a 0w20?

 

[Garak]

Originally Posted By: skyactiv
I noticed there was a rash of Canadians preferring thicker oils at one time.

I'm still using an elevated HTHS 5w-30.

 

[tig1]

Originally Posted By: Zee09
Originally Posted By: Shannow
Originally Posted By: tig1
Oh NO!! Another "Thick VS Thin" thread!

Here it is another tig1 post that he didn't get in first extolling the fact that he ran 5W20 before Ali Hass, in an engine that called for 10W40, and showing the flogging horse emoticon.


+117


I knew someone would bit!! LOL.

 

[PimTac]

Air gun likes his emoticons.

 

[camrydriver111]

Originally Posted By: ZeeOSix
Originally Posted By: walterjay
My SantaFe owners manual says I can run 5-20 or 20-50 depending on the temperature. I always use 5-30


KIA has some common sense, doesn't care about the "CAFE Police".

So do you think automakers are like "We need to increase fuel economy, throw some 0W20 or 0W16 in the engines!"

Or are modern engines designed with these lightweight oils in mind?

Or does it even matter? Can I run 20W50 and the car won't know the difference?

 

[SilverFusion2010]

The newer engines are being designed with the lighter oils in mind. Wider main bearings, anti friction coatings etc

 

[bluesubie]

Originally Posted By: camrydriver111

Aren't engines designed to use a specific viscosity range based on clearances? ...

Are there engines that don't do so well if you use an oil too thin or too thick? ...

When the Subaru BRZ first came out, there were Subaru techs that attended classes that were told that the BRZ engine was "designed" to use 0W-20. There were also builders that took the engine apart that recommended to stick with 0W-20 due to the clearances.

After the car had been out for a few months(?), it didn't take people long to change their minds after a few bearing failures during track time. It also helped that Subaru Japan allows high HTHS Euro 0W-30 and 5W-40. If that's the case, how could the engine have been "designed" to use 0W-20? I guess that I would buy the comment that the engine was designed with 0W-20 in mind, but not that it was designed to only use 0W-20 due to clearances.

I'm seeing this "designed" language again now that the new Subaru Ascent specs 0W-20. Unfortunately, it's not available in Japan so we do not know what viscosity they would recommend there.

 

[RooflessVW]

Originally Posted By: bluesubie
When the Subaru BRZ first came out, there were Subaru techs that attended classes that were told that the BRZ engine was "designed" to use 0W-20. There were also builders that took the engine apart that recommended to stick with 0W-20 due to the clearances.

After the car had been out for a few months(?), it didn't take people long to change their minds after a few bearing failures during track time. It also helped that Subaru Japan allows high HTHS Euro 0W-30 and 5W-40. If that's the case, how could the engine have been "designed" to use 0W-20? I guess that I would buy the comment that the engine was designed with 0W-20 in mind, but not that it was designed to only use 0W-20 due to clearances.

I'm seeing this "designed" language again now that the new Subaru Ascent specs 0W-20. Unfortunately, it's not available in Japan so we do not know what viscosity they would recommend there.

Filled the bro-in-law's FR-S with Pennzoil 0W-40, which also helped to quiet the fuel pump "chirp" they're famous for.

 

[nap]

Originally Posted By: camrydriver111

So do you think automakers are like "We need to increase fuel economy, throw some 0W20 or 0W16 in the engines!"



I believe that this is the case at least when they backspec an oil to an engine that was designed and manufactured before the oil had been.

 

[ZeeOSix]

Originally Posted By: camrydriver111
So do you think automakers are like "We need to increase fuel economy, throw some 0W20 or 0W16 in the engines!"

Or are modern engines designed with these lightweight oils in mind?

Or does it even matter? Can I run 20W50 and the car won't know the difference?


Originally Posted By: SilverFusion2010
The newer engines are being designed with the lighter oils in mind. Wider main bearings, anti friction coatings etc


Yep, CAFE has caused automakers to strive for higher and higher fuel mileage. Car makers keep going with thinner oils to achieve that goal, which in turn has driven the changes in mechanical design of engines.

 

[aquariuscsm]

I definitely believe that machining has made engines “tighter” allowing the use of thin oils. I remember how some engines from the 70s felt and sounded loose and sloppy compared to today’s,especially domestic 4cyl engines.

 

[ZeeOSix]

Originally Posted By: aquariuscsm
I definitely believe that machining has made engines “tighter” allowing the use of thin oils. I remember how some engines from the 70s felt and sounded loose and sloppy compared to today’s, especially domestic 4cyl engines.


Looking at this graph, it seems there would be more of an issue running thinner oil in larger clearances bearings than the other way around. In either case however, thicker oil will always give more MOFT regardless of bearing clearance.

 

[madeej11]

What's that got to do with what aquariuscsm is saying ?

 

[ZeeOSix]

Originally Posted By: madeej11
What's that got to do with what aquariuscsm is saying ?


He's talking about tight clearances and thin oil viscosity. The graph gives info pertaining to that reationship in terms of MOFT (vs bearing clearance and viscosity), which is an important parameter. Also shows that tight bearings don't blow up with thicker oil, but actually obtain a larger MOFT which helps protect them better. Using thin oil in loose engines isn't such a good thing.

 

[Gokhan]

BMW ///M3 data. All clearances are around the standard 50 microns (0.0020 in) or less. It specs 10W-60 but later they allowed 0W-40.

There is a lot of information and speculation into why the bearings were failing.

Now, let's have a panel that will go through the whole page and decide whether the culprit was the thin oil, thick oil, or something else.

BMW ///M3 bearing-failure analysis

 

[Shannow]

"Standard" bearing clearances in design work start at 0.001" per inch of bearing diameter , making it a ratio, and therefore dimensionless.

There's no "standard 50 microns"

That's why the bearing characterisation curves that you discount have a high reliance on (r/c)...squared nonetheless..the ratio of diameter to clearance is a significant characteristic