Why do people mistakenly believe 5w20 oil is too

[tig1]

Originally Posted By: Eddie
If the OPs statement is true for ALL gas engines then why do some request a 0w20 in the US and a 5w30 everywhere else? Ed


Because 20wt oils are not common in most of the world. Hard to find 20wt. Old school thinking.

 

[stockrex]

If one accepts that most engines will run with most oils.
How long is the question?
But then again, average person will not run an engine long enough to find out.

You want to use the thinnest oil for the best mpg.

 

[cp3]

Originally Posted By: cp3
Originally Posted By: Merkava_4
Has there ever been an engine that runs quiet with 5W-20 ?

That's the question I have. . . . .


My Pentastar is whisper quiet compared to the LE5 Ecotec and even the LX9 in the G6. Both run on Xw30.

Shannow,

Is strictly viscosity dependent? Would a Xw20 & an Xw30 have the same film thickness at the same viscosity?

Should have proof read that, guess I retyped it too many times. It should read...

Is film thickness strictly viscosity dependent?

 

[Trav]

Originally Posted By: svhanc
My biggest question has been why Toyota specs a Xw20 oil in the USA and an Xw30 oil in other countries for the same engine.

I don't doubt that the 20 is sufficient protection, but is 30 better?

I want 300k out of my truck, and I think that Toyota would prioritize CAFE over that since the vast majority of consumers will buy 2 or 3 vehicles to travel 300k.

With all that said, I typically use 30 in summer and 20 in winter, but even then PP is known as a thin 30 that shears to 20. Just makes me feel better I guess.


The reason is simple, its called anticipated use.
In the US There is no possibility the engine will ever see the sort of use during normal operation that it will see in some Euro countries.
Meandering along at 75 Mph at 2500 RPM or less is not detrimental for the engine or the engine oil.

Under these conditions a xw20w in an engine that is spec for xw20w may actually provide better results in the long run due to its cold start properties.
On the other side of that coin without oil cooler or larger sump capacity that same oil may not be the best choice for extended high speed, high oil temp operation.

When subjected to these conditions it is cheaper for the manufacturer just to spec a grade higher than go to the expense of increasing the sump capacity or adding an oil cooler.
In the US there is no reason to use xw30 in a Toyota that is spec for xw20 even in summer.
There are a few engines from other manufacturers that do benefit from a higher viscosity oil than spec because of engine traits that destroy the oil quickly e.g Honda V6 with iVTEC and some Nissan VQ engines.

 

[Richtrashman]

Originally Posted By: A_Harman
Originally Posted By: Richtrashman

OK...Increasing the viscosity increases the separation distance between the moving components, for example the bearing journal and the bearing.

Does that work ?


I

You are mistaken, Rich. Shannow is not saying that the sizes of the parts are changing. He is saying that the oil film thickness is changing when viscosity is increased. When a bearing journal is loaded radially, it runs off-center in the bearing, and the combination of bearing load, diameter, clearance, speed, and oil viscosity combine to generate an oil film that separates the moving surfaces. If all other factors are held the same, an increase in viscosity will cause an increase in oil film thickness. If the oil film thickness is so thin that it allows high points of the bearing and journal to make contact in operation, there will be wear. This is the root of the endless thick vs. thin debate on BITOG. Shannow designs bearings for a living, and he knows what he is talking about. I think he is challenging newbies to delve a little deeper into the fundamentals of hydrodynamic bearings.

Thanks for the explanation! That being said, I don't think that you or I have the ability to test those numbers for protection, so how are we supposed to know what truly does work best? Also ( I am not very bright on this) won't running too heavy an oil cause excess heat if the film is too thick for the clearance or is that impossible? If that's not possible then we should all switch over to 5w 40 and call it a day. Also I know there is more to lube than just bearings so we have to compromise just seems so complicated to find the right combo

 

[Spudislander]

Originally Posted By: wally6934
Originally Posted By: svhanc
My biggest question has been why Toyota specs a Xw20 oil in the USA and an Xw30 oil in other countries for the same engine.

I don't doubt that the 20 is sufficient protection, but is 30 better?

I want 300k out of my truck, and I think that Toyota would prioritize CAFE over that since the vast majority of consumers will buy 2 or 3 vehicles to travel 300k.

With all that said, I typically use 30 in summer and 20 in winter, but even then PP is known as a thin 30 that shears to 20. Just makes me feel better I guess.


From reading posts here on BITOG, i know there are many countries where it is difficult to buy thinner oils like 0W20 or 5W20. So the auto mfg spec out what the people can buy.



The only reason they can't easily buy it is because there is no demand! It is very hard to buy 0w20 in my area except at the dealers. The Mazda dealer carries lots of 0w20 in Mazda bottles and the Toyota dealer carries lots of 0w20 in Toyota bottles. So, I suggest availability has absolutely nothing to do with why they don't spec 0w20 in many other countries. It may have more to do with the fact that in those countries they aren't subject to CAFE fines !!

 

[webfors]

I'll be doing UOAs on our new pentastar for the first while to make sure it's not one of those V6 oil killers. So far UOAs have shown that it is not, but most of those UOAs have been 30 weights.

 

[SwampSurvivor]

Originally Posted By: Phishin
Everyone needs to chill out. Come on fellas.

The reality is.....do what you want. Will a Honda run for 200K+ miles on 0w20? Yes. On 20w50? Yes.

I have no reason evidence, but I don't like putting 20 weight oil in high-revving small 4-cylinder engines. My 2010 Accord sees 5-6k RPM's almost every day. You got to mash the pedals on these cars to merge onto highways, accelerate past an old lady, etc. I'm not going to be putting 20 weight in my Honda. No thanks.

Instead, I use a 30 weight oil....a mix of M1 0w20 and M1 0w40. Because in my mind, I'm doing what's best for my car.

That's all that matters...that I believe what I'm doing is best. Some of us make up our minds on nothing but wrong info, others on experience, and yet others on hard data.


My thoughts are the opposite. My 2.0 I4 duratec doesn't lug, it operates in mid-high RPM band and I feel more comfortable. My Jeep, however, is a slow RPM, loose tolerance engine and wear numbers indicate that a slightly heavier oil is a bit better for them.

People track newer mustangs on 5w-20 and have no problem.

It's a preference.

 

[cp3]

Spud,

See Trav's post, I don't think that the answer to this is any one specific thing, it's a combination of things. CAFE, yes. We may not see any fuel mileage gain by running a thinner oil but extrapolate that 1-2% in controlled testing over a manufacturers entire fleet. Now, as Trav noted, the majority of vehicles in NA are not subject to highly stressed oil so if we control the oil temps that thinner oil also offers adequate protection. As for availability, I'm not going to pretend to know what is involved in bringing oil into another country, I don't even know what the regulations are here. I would also suspect that a lot of that decision lays with the retailers as well which is going to rely, to some extent, on what people buy. If I ran a store I'm not going to stock my shelves with 0w20 only to have to dust them off every 6 months any more than I will by 20w50 to put on my shelf at home and do the same thing.

 

[cp3]

Originally Posted By: webfors
I'll be doing UOAs on our new pentastar for the first while to make sure it's not one of those V6 oil killers. So far UOAs have show that it is not, but most of those UOAs have been 30 weights.


Looking forward to these!

 

[Spudislander]

Originally Posted By: cp3
Spud,

See Trav's post, I don't think that the answer to this is any one specific thing, it's a combination of things. CAFE, yes. We may not see any fuel mileage gain by running a thinner oil but extrapolate that 1-2% in controlled testing over a manufacturers entire fleet. Now, as Trav noted, the majority of vehicles in NA are not subject to highly stressed oil so if we control the oil temps that thinner oil also offers adequate protection. As for availability, I'm not going to pretend to know what is involved in bringing oil into another country, I don't even know what the regulations are here. I would also suspect that a lot of that decision lays with the retailers as well which is going to rely, to some extent, on what people buy. If I ran a store I'm not going to stock my shelves with 0w20 only to have to dust them off every 6 months any more than I will by 20w50 to put on my shelf at home and do the same thing.


Based on the information I have read, it seems that in many (or maybe even most cases), the thinner oil will provide "adequate" protection. So far, that is the impression I have gained.

 

[Rand]

funny thing is in the OP's post depending on which 2001 ranger

the 4.0 ranger was NEVER spec'ed 5w20 its too thin for that engine.

 

[Garak]

Originally Posted By: Zaedock
If you could maintain consistant oil temperature, you probably could.

Maybe if the crank was a bit shorter and tighter, and certainly if it were only doing winter short tripping. It's one engine that wasn't back speced, and I'm sure for good reason.

 

[Zaedock]

Originally Posted By: Garak
Originally Posted By: Zaedock
If you could maintain consistant oil temperature, you probably could.

Maybe if the crank was a bit shorter and tighter, and certainly if it were only doing winter short tripping. It's one engine that wasn't back speced, and I'm sure for good reason.

I didn't see the end play spec, but the rod and crank are just as tight as any modern engine.
How about a test!?
I'm hoping to try 0W20 in a Jeep 2.5 (when life throws a bit of time my way)

 

[Finz]

Originally Posted By: Trav
Originally Posted By: svhanc
My biggest question has been why Toyota specs a Xw20 oil in the USA and an Xw30 oil in other countries for the same engine.

I don't doubt that the 20 is sufficient protection, but is 30 better?

I want 300k out of my truck, and I think that Toyota would prioritize CAFE over that since the vast majority of consumers will buy 2 or 3 vehicles to travel 300k.

With all that said, I typically use 30 in summer and 20 in winter, but even then PP is known as a thin 30 that shears to 20. Just makes me feel better I guess.


The reason is simple, its called anticipated use.
In the US There is no possibility the engine will ever see the sort of use during normal operation that it will see in some Euro countries.
Meandering along at 75 Mph at 2500 RPM or less is not detrimental for the engine or the engine oil.

Under these conditions a xw20w in an engine that is spec for xw20w may actually provide better results in the long run due to its cold start properties.
On the other side of that coin without oil cooler or larger sump capacity that same oil may not be the best choice for extended high speed, high oil temp operation.

When subjected to these conditions it is cheaper for the manufacturer just to spec a grade higher than go to the expense of increasing the sump capacity or adding an oil cooler.
In the US there is no reason to use xw30 in a Toyota that is spec for xw20 even in summer.
There are a few engines from other manufacturers that do benefit from a higher viscosity oil than spec because of engine traits that destroy the oil quickly e.g Honda V6 with iVTEC and some Nissan VQ engines.

+1...

My wife is from Ireland and we travel there frequently... I'm amazed at how hard they tend to drive there. Putting Xw20 in my father in law's Toyota Venza, given they he drives, would put me on his SL all over again.

 

[jrustles]

Originally Posted By: Shannow

Increase in viscosity increases the clearance between the components then !


Right, I'm still waiting for that one person to argue that a thicker oil film is less optimal from a wear aspect alone vs a thicker oil.


Quote:
Quote:
Some know it alls think they know better than engineers who designed the engines, so be it.

I love this line. I wonder if it was the same engineers who thought three threads could hold spark plugs in the heads of one of Ford's popular V8 engines. That's just one engineering marvel that comes to mind there's others.

My point is engineers are humans too, and no one is perfect.


Exactly. Also the mandate that engineers are made to operate under are rarely the same as ours.

Originally Posted By: Miller88
Clearly, the research that Honda and Ford

Originally Posted By: wally6934

Well lets be fair here. Everyone makes mistakes and fords has made many blunders. But do you think that Fords 20 year study of 20W oils is one big colossal mistake.


What research? The research that engine life is compromised by 30 grades and that better wear performance can be achieved by pushing the boundaries of low viscosity??? Was that the premise of their studies?

Originally Posted By: rikstaker
In the middleast and even countries like singapore..hyundai, honda toyota etc.. use weights like 15w40, 5w40, 0w40 on the very same engines we run 5w20s on...Heck when I was in the middleast honda dealership were using 20w50 until 2006 and then moved to 15w40. 30wts were available where I was, like havoline and fuchs ttian gt 5w30 but the manual did not recommend anything lower 5w30 and 15w40 was the recommended viscosity and thats what all dealers carried and still do.

Is there an end to this thick vs thin debate? Why do manufacturers recommend 5w20 for N.A? Are the making engines with lower tolerances for us? I doubt.


But, but!! Middle East vehicles rarely see severe service and their fuel prices are so high, it makes no sense that they would waste more fuel with thicker oils when they clearly have enough margin of error with that modern engine- look at the Honda/Ford studies

. Driving in the middle east/asia is rather leisurely like cruising through the mountains upon long winding interstates. I wonder what grade UN convoys use in their Land Cruisers, the vehicles their lives depend on to escape gunfire and warzones, you think they're concerned about fuel economy?

 

[CurtisB]

My theory is that an engine designed to run 20 weight oil has an oil pump and oil passages engineered to flow thinner oil, presumably at a much higher output. Perhaps a thin oil flowing at high speed is able to better provide a protective film (and assist in cooling metal to metal surfaces) better than a thicker oil. I could Imagine that a bearing being supplied a fast flowing thin oil is better able to cool and resist heat expansion. Too much heat expansion may cause an increase in bearing to journal tolerance and negate the benefit of a thicker oils ability to provide an effective film. Just my opinion feel free to add or correct me, I'd love to learn.

 

[demarpaint]

Originally Posted By: wally6934
Originally Posted By: demarpaint
Originally Posted By: wally6934
Some know it alls think they know better than engineers who designed the engines, so be it.


I love this line. I wonder if it was the same engineers who thought three threads could hold spark plugs in the heads of one of Ford's popular V8 engines. That's just one engineering marvel that comes to mind there's others.

My point is engineers are humans too, and no one is perfect.


Well lets be fair here. Everyone makes mistakes and fords has made many blunders. But do you think that Fords 20 year study of 20W oils is one big colossal mistake.


Just bringing up a point that's all.

 

[A_Harman]

Originally Posted By: Richtrashman
Thanks for the explanation! That being said, I don't think that you or I have the ability to test those numbers for protection, so how are we supposed to know what truly does work best? Also ( I am not very bright on this) won't running too heavy an oil cause excess heat if the film is too thick for the clearance or is that impossible? If that's not possible then we should all switch over to 5w 40 and call it a day. Also I know there is more to lube than just bearings so we have to compromise just seems so complicated to find the right combo

Yes, it's basically impossible for laymen such as us to test oils and come to a "best" solution. We have to depend on the engine manufacturers' recommendations for the correct viscosity for the conditions, and on the oil manufacturers for adhering to API test specifications. You are basically right in saying that a heavier oil will cause more heat, but there really isn't such a thing as "too thick for the clearance". If a bearing requires a minimum oil film thickness of 5 microns, and you put in an oil thick enough to generate a 10 micron oil film, you have more safety margin before wear can occur. But at the same time, you have very slightly increased friction in the engine because of increased drag of a higher viscosity oil.

 

[y_p_w]

Originally Posted By: A_Harman
Originally Posted By: Richtrashman
Thanks for the explanation! That being said, I don't think that you or I have the ability to test those numbers for protection, so how are we supposed to know what truly does work best? Also ( I am not very bright on this) won't running too heavy an oil cause excess heat if the film is too thick for the clearance or is that impossible? If that's not possible then we should all switch over to 5w 40 and call it a day. Also I know there is more to lube than just bearings so we have to compromise just seems so complicated to find the right combo

Yes, it's basically impossible for laymen such as us to test oils and come to a "best" solution. We have to depend on the engine manufacturers' recommendations for the correct viscosity for the conditions, and on the oil manufacturers for adhering to API test specifications. You are basically right in saying that a heavier oil will cause more heat, but there really isn't such a thing as "too thick for the clearance". If a bearing requires a minimum oil film thickness of 5 microns, and you put in an oil thick enough to generate a 10 micron oil film, you have more safety margin before wear can occur. But at the same time, you have very slightly increased friction in the engine because of increased drag of a higher viscosity oil.

I don't know if "friction" is the right word, because that implies some sort of wear. I prefer "parasitic loss" because that doesn't imply that there's a lack of protection, but that energy is lost to moving stuff around.