Car recommends 5W-30 outside US and Canada vs 0W-20. Run 5W-30 right?

[ZeeOSix]

All of the studies I seen that look at engine wear vs HTHS only show an increase in wear when the oil in the sump has an actual high shear viscosity below 2.6 cP, equivalent to the minimum required for a 0W20 at 150 C sump temperature. A 0W20 at 110 C has an HTHS of 4.8 cP, which is far higher than is needed for ideal engine protection. Even with a lot of fuel dilution in a GDI engine, it should get no lower than 4.0 (anybody know how to calculate this accurately?).

You're not looking at it quite right. It's not the "sump temperature" that the HTHS spec is talking about ... it's the actual oil temperature and resulting viscosity from the temperature rise going on between the moving parts that are shearing the oil. At higher RPM, the shear rate can even be higher than the 1M/sec used in the HTHS spec test. Tight journal bearings can make the oil temperature inside the bearing skyrocket at higher RPM. The thinner the MOFT, the more sensitive the oil layer is to shear heating. It's what's going on inside the bearings that matters the most. Of course a higher sump oil temperature will also increase the oil temperature on top of the temperature rise from shearing.

If I had a GDI engine that speced xW-20 I'd be dumping that and running xW-30 for fuel dilution headroom for sure, even if it wasn't a strong diluter. It doesn't take a lot of fuel dilution to lower the viscosity of the oil.

 

[Danh]

WOOOSH. His point was that in hotter climates you want a higher viscosity oil due to higher temps resulting in greater viscosity reduction. Towing in Vancouver vs towing in south Texas, for example, one would be more inclined to run a higher viscosity oil in south Texas due to the heat.

Further... 20 is far from "pretty thick." Product data sheets make that clear. My bike calls for 40 weights, the mower/blower for 30. Why would I want less protection for a modern engine? For .5 MPG? I'll stick with my 30s and 40s.

FWIW, I'm an auto tech. The number of vehicles I service DAILY using xw20 oils that are 1-2 quarts low or more is staggering. From the Korean makes, to American domestics, to Japanese. Most of our clients with German cars still have them spec'd for 30 or 40 weight. And some newer RAMs and Jeeps are spec'd for xw40 euro. There's a LOT of merit to thicker and very little for thinner. Maybe some makes/engines are fine on a 20, but I think you're rolling the dice. Engines are expensive and can take a while for problems to develop. Remember that.

If your bike and mower/blower are air cooled, there’s your answer.

 

[Trav]

gutless 3800? Have you ever had a car with one? Drove an '89 bonneville for a few years that had gobs of power. Maybe you just need cars with turbos? After all, power/performance is relative as well. My superhawk 996 could take me well north of 130 MPH, but in a car the 3800 never left me wanting more.

The 3800 is reliable (once the intake gaskets are replaced with aluminum frame ones) but in stock form it is slower than molasses in January especially in a 3500 lb car, they can be worked to be real quick but not on the cheap.

 

[TiGeo]

Also in the Coyote used in their trucks. That's a lot of trucks that Ford is missing out on CAFE credits. Those vehicles make up a big chunk of their overall production numbers.

I don't know a thing about CAFE - so they either get or don't get this credit based on 20W vs. 30W?

 

[ZeeOSix]

Even with a lot of fuel dilution in a GDI engine, it should get no lower than 4.0 (anybody know how to calculate this accurately?).

Use this on-line viscosity calculator, and use 0.55 cSt for gasoline at 100C for "Oil #1", and percentage of fuel dilution for "Percentage of oil #1". Example below shows that 1% fuel dilution lowered the KV100 from 13.5 to about 13 cSt.

https://www.widman.biz/English/Calculators/Mixtures.html

More Examples:
Starting with a KV100 of 13.5 cSt.
1% fuel dilution makes it go down to 13.03
2% fuel dilution makes it go down to 12.57
3% fuel dilution makes it go down to 12.14
4% fuel dilution makes it go down to 11.72
5% fuel dilution makes it go down to 11.32
10% fuel dilution makes it go down to 9.55
15% fuel dilution makes it go down to 8.09

You can do your own examples starting with a thin xW-20 or xW-16 oil.

 

[Jimmy_Russells]

I don't know a thing about CAFE - so they either get or don't get this credit based on 20W vs. 30W?

It's so important than brands like Stellantis continue to pump out Hellcat after Hellcat of virtually everything and anything
/s

 

[ZeeOSix]

I don't know a thing about CAFE - so they either get or don't get this credit based on 20W vs. 30W?

CAFE = Corporate Average Fuel Economy. So the company's "feet" must meet the CAFE standards, or otherwise pay fines for missing the targets. If they are not doing all their MPG ratings on thinner oil, then they will have a tougher time meeting the CAFE targets ... and those targets are always moving higher. That's why specified oils have gotten thinner and thinner over the years ... it's all CAFE driven, not driven by tribology and the need to better protect engines. The farther away the fleet misses the targets, the more the company has to pay. Of course, the company can just jack up the price of the vehicles ... guess that's why a loaded F-150 is nearing $100K.

https://www.transportation.gov/mission/sustainability/corporate-average-fuel-economy-cafe-standards

 

[Jackson_Slugger]

Japan has its own "CAFE" that regulates vehicle fuel economy, and their fuel mileage targets are more lofty than CAFE in the USA. Probably why Japan has been developing and using super thin oils for wuite awhile.

https://www.transportpolicy.net/standard/japan-light-duty-fuel-economy/

Yes as I said. But a few years back they were actually thicker and still had the 5W-30 standard after going to 5W-20 here...

Many Euro nations still (but not always) recommend thicker oil. But they historically have had longer drain intervals and unlike here, cannot "recommend" a single grade of oil. My friends '15 Audi can use anything from 0W-30 to 5W-40. And of course at prices that will make you extend your oil change....

 

[Bjornviken]

Greetings! (-wave)
It's not that it will blow up, it's just not optimal I guess! But, I don't disagree with you!
I've been very curious about this myself. Can we use a heavier oil in an engine that requires a 0W16?

All of the Toyota's that I've driven recently that require 0W16 oil, was a noisy engine(upon acceleration) and I was curious if a thicker oil would quiet them down.

Have you noticed any difference, or didn't you think your engine was noise to begin with?
My BIL has a 2018 Camry 2.5 XLE and is on his 3rd or 4th Camry.

IMO, recent Toyota 4 cyl's are noisy(er). When if fact, Toyota 4 cyl's used to be a model of smooth & quiet operation.

try m1 0w-40, it will

 

[Olinskis]

I don't know a thing about CAFE

AH, now it makes sense. Thanks for the context friend!

 

[nthach]

I’m running 5W-30 in a car that sees a hard life, Toyota calls for 0W-20 but I’m using a loophole in the OM. Same thing with a TGDI Subaru but with a Euro ACEA C3 oil. Now, if the car lives an “easy” life, not taken on long road trips or things like that, I have no issue with 0W-20. But I’ll use thicker(within reason) oils if I find a way out.

 

[twX]

You're not looking at it quite right. It's not the "sump temperature" that the HTHS spec is talking about ... it's the actual oil temperature and resulting viscosity from the temperature rise going on between the moving parts that are shearing the oil. At higher RPM, the shear rate can even be higher than the 1M/sec used in the HTHS spec test. Tight journal bearings can make the oil temperature inside the bearing skyrocket at higher RPM. The thinner the MOFT, the more sensitive the oil layer is to shear heating. It's what's going on inside the bearings that matters the most. Of course a higher sump oil temperature will also increase the oil temperature on top of the temperature rise from shearing.

I'm aware that the oil will be hotter in the bearings. I was referring to sump temperature because the studies I was referring to had designs that maintained oil sump temperature to around 150 C, and did not measure bearing temperatures. There was no increased wear at a high shear viscosity of 2.6 cP based on oil temperature in the sump, even though the oil viscosity in the bearings would have been much lower. It seems that the actual high shear viscosity within the bearing can get a lot lower than 2.6 cP.

 

[Drew7a]

Have you noticed any difference, or didn't you think your engine was noise to begin with?
My BIL has a 2018 Camry 2.5 XLE and is on his 3rd or 4th Camry.

I have no way to scientifically quantify if it is quieter than before. Unscientifically it does appear to be quieter.

As I have posted before as my stash of oil runs down any new oil I buy will be 0w-30 or 0w-40 for my universal oil.

But to each his own on what they want to use. Last I checked still somewhat of a free country.

 

[ZeeOSix]

I'm aware that the oil will be hotter in the bearings. I was referring to sump temperature because the studies I was referring to had designs that maintained oil sump temperature to around 150 C, and did not measure bearing temperatures. There was no increased wear at a high shear viscosity of 2.6 cP based on oil temperature in the sump, even though the oil viscosity in the bearings would have been much lower. It seems that the actual high shear viscosity within the bearing can get a lot lower than 2.6 cP.

"Maintained oil sump temperature around 150C"? ... seems pretty high if that was the normal operating sump temperature. I could see if that was a max allowed and the oil cooling system was designed to maintain 150C or below in the worse operating conditions ever seen.

Back in post #111 you said: "A 0W20 at 110 C has an HTHS of 4.8 cP, which is far higher than is needed for ideal engine protection."

A 0W-20 at 110C might have a KV100 (the kinematic viscosity at 110C) of 4.8 cSt (not cP), but it's going to have a much lower HTHS viscosity ... like 2.5-2.6 cP. KV100 and HTHS have different units of viscosity (cSt vs cP) because KV100 is the kinematic viscosity and HTHS is dynamic viscosity. The latter is a better representation of an oil under dynamic shear.

The actual running viscosity inside a journal bearing could become less than the HTHS rating/spec of the oil if the shear rate is higher than 1M/s and/or the searing inside the bearing raised the oil temperature above 150C. HTHS is defined and tested at 150C and a shear rate of 1M/s (1,000,000 per second). Also, as shown earlier, fuel dilution can reduce the KV100, which will also reduce the HTHS viscosity. What's the best and easiest way to ensure adequate HTHS viscosity and resulting MOFT headroom to cover all possible driving situations? Use a thicker oil.

 

[PimTac]

I don't know a thing about CAFE - so they either get or don't get this credit based on 20W vs. 30W?

AH, now it makes sense. Thanks for the context friend!

You missed a part of his quote.


It’s been around almost 50 years. Still the bane of Bitogers

 

[twX]

"Maintained oil sump temperature around 150C"? ... seems pretty high if that was the normal operating sump temperature. I could see if that was a max allowed and the oil cooling system was designed to maintain 150C or below in the worse operating conditions ever seen.

I took another look at the papers I have. SAE Paper 980702 mentions a test oil temperature of 149 C. It isn't mentioned where the oil temperature was measured. I assumed it to be the pre-bearing temperature. The test setup only includes a single bearing.

SAE 892154 mentions a sump temperature of 150 C at 5800 rpm, and 136 C at 3000 rpm, both at WOT on a chassis dyno, with a water-cooled heat exchanger installed in the sump to control oil temperatures.

The only study I have on hand that studies piston ring wear is the Japanese one. In that case the oil temperature was maintained at either 90 C or 130 C. The test setup used an oil heater, and it was a complete engine tested so I assume that these are sump temperatures. Unfortunately, I can't read Japanese Increased wear is seen at 2.4 cP HTHS oil (the high shear viscosity at the test temperature of 130 C is 3.1 cP).

A 0W-20 at 110C might have a KV100 (the kinematic viscosity at 110C) of 4.8 cSt (not cP), but it's going to have a much lower HTHS viscosity ... like 2.5-2.6 cP. KV100 and HTHS have different units of viscosity (cSt vs cP) because KV100 is the kinematic viscosity and HTHS is dynamic viscosity. The latter is a better representation of an oil under dynamic shear.

I'm pretty sure that 4.8 cP (not cST) is more or less the correct high shear dynamic viscosity at 110 C. HTHS is defined at 150 C, but high shear dynamic viscosity can be calculated for different temperatures. The Japanese study indicates that their 5W20 with an HTHS of 2.6 cP has a high shear viscosity of 3.5 cP at 130 C and 7.4 cP at 90 C.

I used data for Pennzoil Platinum 0W20, which I assumed to be 2.6 cP at 150 C with a KV40 of 43.4, KV100 of 8.6, and calculated KV110 of 7.14 cST, and KV150 of 3.90 cST. I estimated HS viscosity at 110 C to be 7.14/3.90*2.6 = 4.8 cP.

 

[1BadManVan]

I towed a 5,000 pound travel trailer with a Silverado 5.3 running 0w/20 all over the Rocky Mountains and the motor didn't blow up.

Same boat as you! Tow a 5k travel trailer through the Canadian Rockies every year, 0w20 Mobil 1 EP in my 5.7 hemi. Zero issues, don’t even have the infamous loud hemi start up tick after 86k so far

 

[TiGeo]

Same boat as you! Tow a 5k travel trailer through the Canadian Rockies every year, 0w20 Mobil 1 EP in my 5.7 hemi. Zero issues, don’t even have the infamous loud hemi start up tick after 86k so far

pfffffff....just lies made up by the thin-oil biased media

 

[ZeeOSix]

I took another look at the papers I have. SAE Paper 980702 mentions a test oil temperature of 149 C. It isn't mentioned where the oil temperature was measured. I assumed it to be the pre-bearing temperature. The test setup only includes a single bearing.

SAE 892154 mentions a sump temperature of 150 C at 5800 rpm, and 136 C at 3000 rpm, both at WOT on a chassis dyno, with a water-cooled heat exchanger installed in the sump to control oil temperatures.

If the sump temperature was 150C, then the oil temperature inside the bearing is going to be even higher due to the oil shearing. And the tighter the bearing clearance, and higher the RPM, the higher the oil temperature rise in the bearing. Tight bearings can smoke themselves much easier than looser bearings. Bearing clearance at or below 0.001 really impacts bearing oil temps due to shearing - along with higher RPM and load on the bearing. This is why oil temps get real high on cars used on the track.

The only study I have on hand that studies piston ring wear is the Japanese one. In that case the oil temperature was maintained at either 90 C or 130 C. The test setup used an oil heater, and it was a complete engine tested so I assume that these are sump temperatures. Unfortunately, I can't read Japanese Increased wear is seen at 2.4 cP HTHS oil (the high shear viscosity at the test temperature of 130 C is 3.1 cP).

Yes, I have that one too ... sounds like this one. Throw thin oil on top of more shearing with increased RPM and you get this. Ring wear (like most components) wear more with increased oil shearing due to RPM and load. Of all the wear studies I've read, it seems the piston rings have a rough life and can wear faster than other engine components. Of course, ring material is also very key to mitigate their wear.

I'm pretty sure that 4.8 cP (not cST) is more or less the correct high shear dynamic viscosity at 110 C. HTHS is defined at 150 C, but high shear dynamic viscosity can be calculated for different temperatures. The Japanese study indicates that their 5W20 with an HTHS of 2.6 cP has a high shear viscosity of 3.5 cP at 130 C and 7.4 cP at 90 C.

I used data for Pennzoil Platinum 0W20, which I assumed to be 2.6 cP at 150 C with a KV40 of 43.4, KV100 of 8.6, and calculated KV110 of 7.14 cST, and KV150 of 3.90 cST. I estimated HS viscosity at 110 C to be 7.14/3.90*2.6 = 4.8 cP.

You didn't make it clear that you were estimating the HTHS at a lower temperature in post #111. But fact is, you can't determine the actual temperature inside the bearings by looking at the sump temperature ... there is no connection. The temperature rise in the bearing is a function of the oil viscosity, MOFT inside the bearing and the speed of the bearing (shear rate of the oil).

 

[Bill7]

But is it? Again and again here folks say that using the higher grade oil for shorter duration is the way but I'm still waiting to see overwhelming evidence-supported information. Otherewise, this is 100% based on feel.

I did a few engine flushes with Liqui Moli on each of my 4 vehicles when I first bought them as used vehicles.
My maintenance is very simple now:
I do short 4k/6 month OCI's with a good full Synthetic 5W-30 to keep engine wear to an absolute minimum, and prevent sludge.