0W-20 in Winter and 5W-20 in Summer?

[Gokhan]

Originally Posted By: KrisZ
There is this tiny, little detail in the engine called bearings.

if the oil's HTSV goes below the minimum spec (as indicated by oil pressure) they may go boom.

You should keep this in mind before you blindly recommend 0w20 oil based on nothing more than your butt dyno.

You may have learned about HTHS viscosity and bearing protection from my posts here. I have detailed posts about that, some giving technical formulas about the operation of the hydrodynamic bearings. Also keep in mind that it's not just the bearings but also the rings and linings that benefit from a higher HTHS viscosity.

However, you have completely missed the point. The original poster's engine recommends 5W-20 dino. You can use 0W-20 synthetic in all applications requiring 5W-20 dino, as the two oils have identical HTHS viscosity and similar or identical kinematic viscosities. On top of that, 0W-20 will actually run thicker at the top cylinder rings, where the temperatures can exceed 200 C. This is due to the higher viscosity index of 0W-20. Therefore, 0W-20 is actually thicker than 5W-20 where the lubrication is most critical. Not to mention other enormous benefits of synthetics over dino, such as better oxidation properties, lower NOACK volatility, and better fuel economy (as they have lower surface friction due to better base oil and they maintain it longer due to less oxidation).

PS: 5W-20 synthetic will have lower NOACK and less VIIs and therefore be slightly more robust than 0W-20 synthetic, but I still prefer 0W-20 due to its higher viscosity index, which not only improves the fuel economy and saves you money but may protect better at extreme temperatures (such as top rings) and also can imply a higher-quality base oil, as the quality of the base oil correlates with the viscosity index. In fact, most 0W-20s these days are using Group III+ versus Group III used in 5W-20s. I see little reason to prefer 5W-20 synthetic over 0W-20 synthetic, as the 0W-20 synthetic is a far more advanced oil with many important benefits. Besides, you will void the warranty of many new Japanese cars if you use 5W-20 instead of 0W-20. I think in the future, 0W-20 will completely replace 5W-20, just as 5w30 replaced 10w30.

 

[CATERHAM]

Originally Posted By: Gokhan
Originally Posted By: CATERHAM
Originally Posted By: Gokhan
Originally Posted By: CATERHAM
Yes, but when oil temp's are referenced it's always bulk oil sump temp's. With 20wt applications oil temp's are low.
But as you've mentioned, one main advantage of high VI oils is that the viscosity doesn't change as much with temperature change.
So if one optimizes the operational viscosity of a ultra high VI oil at normal operating temp's of say 90C, if the oil temp's rise in extreme useage the viscosity will thin out less and in the hottest part's of the engine the oil will be thicker than it would be otherwise with a low VI oil.

To give an example. In switching to the 229 VI Sustina 0W-20, I expected the oil to be lighter than the Toyota 0W-20 but was surprised how much lighter it still was at 80C oil temp's, in fact 10% lighter in terms of oil pressure which correlates with HTHSV. So to maintain the minimum OP that I wanted I had to add just over 10% of Sustina 0w50 (HTHSV est 3.85cP) to equal the OP with the undoctored Toyota 0W-20. So I've now got the same operational viscosity as before but now I'm running a 0W-20 oil with a HTHSV of 2.75cP. So in the hottest parts of the engine the oil is effectively heavier with more protection.

The Japanese move to ultra high VI 0W-20 swynthetic oils accomplishes many goals. It enables then to run a lighter oil that's still legitimately called a 20wt under the SAE classifications that ignores the VI effect. The bearing wiping point has undoubtedly been lower somewhat, but since the oil is synthetic usually with a robust AW add' pac' that difference has been amelioreated vs a typical dino. Besides modern engine management systems will prevent the oil from getting too hot.

I don't understand what you are trying to do by optimizing the kinematic viscosity (which is related to the oil pressure) at the normal operating temperature. Are you trying to optimize for less engine friction? Why are you worried about the oil pressure being a little too lower than you think it should be -- it should have no effect at all on the lubrication efficiency.

Kinematic viscosity doesn't relate to oil pressure, HTHSV does or rather the OP back-pressure reading on an OP gauge.
An OP gauge is a viscometer, consiquently maintaining a certain minimum OP reading on an OP gauge is the same as maintaining a certain minimum operational viscosity.

HTHS viscosity is measured at a shear rate of 1,000,000 1/second, with the oil being rapidly sheared between two sliding parts, with the shear rate being defined as the speed divided by the distance. At such high-shear rates, VIIs temporarily shear, reducing the dynamic viscosity of the oil. This has no relation to what goes at the oil pump, lubrication stream, or the oil-pressure gauge. You have a laminar flow at the lubrication stream, which means only the kinematic viscosity applies.

Your lack of hands on experience is quite evident.
If you know the HTHSV rating of an oil (even at 150C although it is measured at other temp's as well) you can disregard the kinematic viscosity measure at 100C. The HTHSV measure is sometimes referred to as "bearing viscosity" since the measure closely replicates the conditions similar to those in an operating engine. Since an oil pressure gauge basically measures the resistance to oil flow through the bearings of an operating engine, the higher the HTHSV of an oil, the higher the oil pressure reading on an OP gauge. The correlation is very precise.
The same correlation doesn't apply to the kinematic measure since varing oil chemistries have different viscosity-pressure coefficients.

 

[KrisZ]

Originally Posted By: Gokhan
However, you have completely missed the point. The original poster's engine recommends 5W-20 dino. You can use 0W-20 synthetic in all applications requiring 5W-20 dino, as the two oils have identical HTHS viscosity and similar or identical kinematic viscosities. On top of that, 0W-20 will actually run thicker at the top cylinder rings, where the temperatures can exceed 200 C. This is due to the higher viscosity index of 0W-20. Therefore, 0W-20 is actually thicker than 5W-20 where the lubrication is most critical.


Where are you getting the part that 0w20 will be thicker than 5w20 from? Just because it has more viscosity improvers? In most multigrades aren't VI's added to prevent thickening? Also the viscosity improvers are usually the first ones to break down due to shear and high temps, so how is that oil going to look like with some miles on it?
As others stated, high VI's don't mean squat all by themselves, it's the whole package that matters.

And no, I did not miss the point that OP's application calls for 5w20. But the moment you started claiming higher viscosity and better protection, red flags went off in my mind.

 

[Gokhan]

Originally Posted By: CATERHAM
Your lack of hands on experience is quite evident.
If you know the HTHSV rating of an oil (even at 150C although it is measured at other temp's as well) you can disregard the kinematic viscosity measure at 100C. The HTHSV measure is sometimes referred to as "bearing viscosity" since the measure closely replicates the conditions similar to those in an operating engine. Since an oil pressure gauge basically measures the resistance to oil flow through the bearings of an operating engine, the higher the HTHSV of an oil, the higher the oil pressure reading on an OP gauge. The correlation is very precise.
The same correlation doesn't apply to the kinematic measure since varing oil chemistries have different viscosity-pressure coefficients.

I will mostly disagree with you in that you can relate the oil-pressure reading on the gauge to the HTHS viscosity (@ T = 150 C, shear rate = 1,000,000 1/second). The lubrication circuit is pretty large and parts of it are low-shear and parts of it are high-shear. On top of that, in the bearings, the oil-film thickness varies greatly and the HTHS viscosity only applies at the point of the minimum oil-film thickness (MOFT), where the shear rate is the greatest. The shear rate (relative speed of the sliding parts divided by the relative separation between them) at other points in the bearing will be much less than 1,000,000 1/second, the shear rate at which the HTHS viscosity is normally measured. In addition to these important points, there are probably many other factors going into place, and trying to infer the HTHS viscosity -- which only applies at the MOFT -- by looking at the oil-pressure gauge is I think quite a bit of a stretch.

 

[il_signore97]

Originally Posted By: CATERHAM

Your lack of hands on experience is quite evident.


Condescending remarks such as this one are not necessary and add nothing to the credibility of an explanation.

 

[Shannow]

Originally Posted By: il_signore97
Originally Posted By: CATERHAM

Your lack of hands on experience is quite evident.


Condescending remarks such as this one are not necessary and add nothing to the credibility of an explanation.


They are just SOP to some of the elite on the board at the present time.

 

[skyship]

Gohkan,
I think in the future, 0W-20 will completely replace 5W-20, just as 5w30 replaced 10w30.

It all depends on the cost of the oil for the cheaper car engines. 0/20 might be better, but for many car manufacturers the only thing that matters is cost, so the question will be which is cheaper and I bet the final answer will be 10/20 for most climates and 5/20 for very cold countries. The 5/20 and 10/20 will be cheap conventional oils and when you bear in mind that the cheap car companies are not changing their main block specs to match the lower viscosity oils, then the situation starts to look interesting in long term engine life terms. The final worm in the can is the push for longer OCI's to save the dealer money when the car is under initial warranty and to convince potential new owners that the new car requires very little servicing.
Put all three negative factors together and the cheaper cars using 5/20 and longish OCI's are going to suffer. The ones at real risk will be ones owned by boy racers that get stuck in traffic jams a lot. The varnish and sludge will restrict oil flow, but then the big right boot will finish the job.

 

[Greggy_D]

Originally Posted By: Shannow
Originally Posted By: il_signore97
Originally Posted By: CATERHAM

Your lack of hands on experience is quite evident.


Condescending remarks such as this one are not necessary and add nothing to the credibility of an explanation.


They are just SOP to some of the elite on the board at the present time.


+1

 

[meb]

I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.

 

[skyship]

Originally Posted By: meb
I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.


Always DYOR and spend some time looing at the German web site oil finder guides for Liqui moly, Castrol, Mobil and Shell. Once you have seen the truth, go find the US version.

 

[meb]

I understand DTOR for sure. Which German website? I looked here...perhaps I missed it. Thanks.

 

[Gokhan]

Originally Posted By: meb
I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.

I am not sure if you're actually asking for the comparison of 0W-40 and 5W-40, but if you're are, to my surprise as well, 0W-40s outperformed 5W-40s by far at high-temperature-cooking tests. While the 0W-40s stayed stable, 5W-40s turned into sludge:

Russian high-temperature tests of oils

My personal explanation for this is that 5W-40s use cheaper base oil (albeit still being synthetic), which results in the need for a lot of viscosity-index-improver polymers (needed to make the really large xW-y spread), which can decompose at high temperatures. Cheaper base oil also has more oxidation.

Now, it's not that your engine will be subject to such very high temperatures (unless it's turbo etc.), but it looks like 0W-40s are better-quality oils.

However, 5W-40s are usually a bit thicker, which may benefit you in some motorcyle and heavy-duty applications. On top of that, 5W-40s are specifically tailored toward heavy-duty applications (including great soot handling) to begin with and certainly should be the preferred oil for large diesel engines (soot-coughing monsters) and perhaps even smaller diesel engines.

The cost of the 5W-40s will be less though, due to their cheaper base oil. Again, they are more tailored toward diesels (not that they wouldn't work in gas engines). 0W-40s are more tailored toward gas and some small diesel engines.

 

[Trav]

Thanks for your explanations, very understandable, i appreciate you making some things clearer.

This point has me particularly interested..
Quote:
5W-40s use cheaper base oil (albeit still being synthetic), which results in the need for a lot of viscosity-index-improver polymers (needed to make the really large xW-y spread), which can decompose at high temperatures.


This fits the PP and PU argument perfectly. One poster here claims he would take PP over the PU because it thinner and has higher VI.

Its been my opinion that the PU with its superior base stocks doesn't need higher VI ans is probably a more stable product.
Maybe thats why it can keep engines cleaner better than other Pennzoil products.

Is it your opinion that two oils of the same viscosity one with high VI and a mediocre base stock will cause more deposits than an oil with high grade base stocks and lower VI under severe conditions?

 

[Gokhan]

Originally Posted By: Trav
Is it your opinion that two oils of the same viscosity one with high VI and a mediocre base stock will cause more deposits than an oil with high grade base stocks and lower VI under severe conditions?

It's really hard to say but the base stock definitely makes a difference. Some Group III+ and IV base stocks have inherently high viscosity indexes and don't require a large concentration of VIIs for that reason. Group III+, IV, and V base stocks also have great oxidation properties. I think that's the case with the 0W-40s. They not only have quality base stocks but also have a smaller concentration of VIIs I think. It's possible that the quality of the VIIs and detergent-inhibitor package varies with the quality of the oil as well, which may also help things at high temperatures. 0W-20s tested there did pretty well -- remarkable considering how thin the base stocks of these oils are at low temperatures. I wish they would have the Toyota 0W-20 so that we could see how it would perform. I think you're implying that it probably has a very high concentration of VIIs due to its ultra-high viscosity index and may perform poorly, but I would have liked to see actual tests.

 

[meb]

Thank you! I use the 0W40 in a VW 2.0 turbo. It was suggested above that I search German websites for more oil information...not sure which one(s), but can I determine the quality of base stock from the bottle of oil? If you were to direct me, what required reading would you suggest? I am simply trying to learn more about a subject I thought I was somewhat famiiar with...I am not at all.

Originally Posted By: Gokhan
Originally Posted By: meb
I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.

I am not sure if you're actually asking for the comparison of 0W-40 and 5W-40, but if you're are, to my surprise as well, 0W-40s outperformed 5W-40s by far at high-temperature-cooking tests. While the 0W-40s stayed stable, 5W-40s turned into sludge:

Russian high-temperature tests of oils

My personal explanation for this is that 5W-40s use cheaper base oil (albeit still being synthetic), which results in the need for a lot of viscosity-index-improver polymers (needed to make the really large xW-y spread), which can decompose at high temperatures. Cheaper base oil also has more oxidation.

Now, it's not that your engine will be subject to such very high temperatures (unless it's turbo etc.), but it looks like 0W-40s are better-quality oils.

However, 5W-40s are usually a bit thicker, which may benefit you in some motorcyle and heavy-duty applications. On top of that, 5W-40s are specifically tailored toward heavy-duty applications (including great soot handling) to begin with and certainly should be the preferred oil for large diesel engines (soot-coughing monsters) and perhaps even smaller diesel engines.

The cost of the 5W-40s will be less though, due to their cheaper base oil. Again, they are more tailored toward diesels (not that they wouldn't work in gas engines). 0W-40s are more tailored toward gas and some small diesel engines.

 

[OpelFever]

Tom NJ comments on the oil "test"

Originally Posted By: Tom NJ


Cooking an oil at over 700°F in a glass flask and visually evaluating the sludge formed is utterly meaningless. The conditions are not even close to an automotive engine and no correlation to engine performance has been established. No scientific conclusions whatsoever can be drawn from such testing, and the results are more apt to mislead than guide.

The engine and/or fleet tests conducted for certification under API, ILSAC, and ACEA standards are run is actual engines under very severe conditions with standardized equipment and procedures and all variables under control. These are the only scientifically valid methods for evaluating motor oil performance in engines. Everything else is marketing.

Your best guide for selecting motor oils is certification under the official specifications relevant to your engine/environment/driving pattern.

Tom NJ


Furthermore the is no correlation between base oil and sludge formation in that test. "Watered-down lowly group III Mobil 1 0w-40" beat Redline racing oil and Motul 300V which supposedly contain the best base oils. Total 10w-40 with dino basestock beat the majority of 5w-40 and 0w-40 synthetics.

 

[tig1]

That test is more of a stunt than a real test of engine oil.

 

[Gokhan]

Originally Posted By: OpelFever
Tom NJ comments on the oil "test"

Originally Posted By: Tom NJ


Cooking an oil at over 700°F in a glass flask and visually evaluating the sludge formed is utterly meaningless. The conditions are not even close to an automotive engine and no correlation to engine performance has been established. No scientific conclusions whatsoever can be drawn from such testing, and the results are more apt to mislead than guide.

The engine and/or fleet tests conducted for certification under API, ILSAC, and ACEA standards are run is actual engines under very severe conditions with standardized equipment and procedures and all variables under control. These are the only scientifically valid methods for evaluating motor oil performance in engines. Everything else is marketing.

Your best guide for selecting motor oils is certification under the official specifications relevant to your engine/environment/driving pattern.

Tom NJ


Furthermore the is no correlation between base oil and sludge formation in that test. "Watered-down lowly group III Mobil 1 0w-40" beat Redline racing oil and Motul 300V which supposedly contain the best base oils. Total 10w-40 with dino basestock beat the majority of 5w-40 and 0w-40 synthetics.

No, Total Quartz 10W-40 is a full synthetic. That was already discussed elsewhere. Please read it first before you claim otherwise.

Mobil 1 0W-40 is probably a combination of Group III+, IV, and V -- with no Group III. Group III is used in 5W-40 HDEOs, which are significantly cheaper.

The tests they did are actually quite similar to "hot-tube tests," which are standard for testing expected performance in a turbocharger-equipped engine -- the most demanding kind of engine. It's the crucial part of the Honda/Acura HTO-06 etc. tests.

 

[skyship]

Originally Posted By: meb
Thank you! I use the 0W40 in a VW 2.0 turbo. It was suggested above that I search German websites for more oil information...not sure which one(s), but can I determine the quality of base stock from the bottle of oil? If you were to direct me, what required reading would you suggest? I am simply trying to learn more about a subject I thought I was somewhat famiiar with...I am not at all.

Originally Posted By: Gokhan
Originally Posted By: meb
I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.

I am not sure if you're actually asking for the comparison of 0W-40 and 5W-40, but if you're are, to my surprise as well, 0W-40s outperformed 5W-40s by far at high-temperature-cooking tests. While the 0W-40s stayed stable, 5W-40s turned into sludge:

Russian high-temperature tests of oils

My personal explanation for this is that 5W-40s use cheaper base oil (albeit still being synthetic), which results in the need for a lot of viscosity-index-improver polymers (needed to make the really large xW-y spread), which can decompose at high temperatures. Cheaper base oil also has more oxidation.

Now, it's not that your engine will be subject to such very high temperatures (unless it's turbo etc.), but it looks like 0W-40s are better-quality oils.

However, 5W-40s are usually a bit thicker, which may benefit you in some motorcyle and heavy-duty applications. On top of that, 5W-40s are specifically tailored toward heavy-duty applications (including great soot handling) to begin with and certainly should be the preferred oil for large diesel engines (soot-coughing monsters) and perhaps even smaller diesel engines.

The cost of the 5W-40s will be less though, due to their cheaper base oil. Again, they are more tailored toward diesels (not that they wouldn't work in gas engines). 0W-40s are more tailored toward gas and some small diesel engines.


EEKS! Some of you are getting base stock quality mixed up with viscosity ranges.
If you ignore base stock quality, a 5w40 will outlast an 0/40 and there is no real difference in high temp shear results. As a general rule the closer the two indexes the longer the oil will last, which is one of the main reasons that many German car manufacturers recommend 5w30 or 5w40 for the ultra long OCI vehicles. BUT that is only true of oils from the same company that use the same quality and base stock type. Many 5w40's are HC Synthetics not real German synthoils (G4 or 5), however you can get Synthoil 5w40 and having spoken to both Liqui Moly and the Volvo dealers senior chaps I can assure you it will last slightly longer.
Not sure about what the other major brands do in terms of base stocks, but the simple test is to look up the dot de web site and see if the oil you are thinking of using is called a full synthetic or synthoil and not synthetic technology or HC synthetic.
In reality the only difference between a top quality 5w40 and an 0/40 is for ultra cold starts, as very few owners use an OCI long enough to discover if the base stock breaks down earlier or not, in fact you will get nearly as good a performance from a top quality major brand conventional oil if your OCI is reasonable.
The Russian bottle test is not of great interest, as very few engines have turbos that fry oil or are driven so hard that short term high temp shearing is a factor and it confuses different viscosity ranges and does not seperate the synthetics. If you are concerned by high temp shearing and varnish formation, look for a Porsch approved oil as their turbos are a real oil killer even with short OCI's and they must be kept very clean due to the increased importance of oil as a coolant.

 

[Gokhan]

Originally Posted By: meb
Thank you! I use the 0W40 in a VW 2.0 turbo. It was suggested above that I search German websites for more oil information...not sure which one(s), but can I determine the quality of base stock from the bottle of oil? If you were to direct me, what required reading would you suggest? I am simply trying to learn more about a subject I thought I was somewhat famiiar with...I am not at all.

Originally Posted By: Gokhan
Originally Posted By: meb
I found this entire thread extremely informative, thank you. So, we non-informed folks typically see a higher numeric number and automatically assume that we're getting better lubrication. So how do we, even if data is over analyzed, select a good oil pre-UOA? I assume a M1 0W40 is better in winter than M1 5W40 and vise versa. But the OP's question brings my assumptions into focus as well.

I am not sure if you're actually asking for the comparison of 0W-40 and 5W-40, but if you're are, to my surprise as well, 0W-40s outperformed 5W-40s by far at high-temperature-cooking tests. While the 0W-40s stayed stable, 5W-40s turned into sludge:

Russian high-temperature tests of oils

My personal explanation for this is that 5W-40s use cheaper base oil (albeit still being synthetic), which results in the need for a lot of viscosity-index-improver polymers (needed to make the really large xW-y spread), which can decompose at high temperatures. Cheaper base oil also has more oxidation.

Now, it's not that your engine will be subject to such very high temperatures (unless it's turbo etc.), but it looks like 0W-40s are better-quality oils.

However, 5W-40s are usually a bit thicker, which may benefit you in some motorcyle and heavy-duty applications. On top of that, 5W-40s are specifically tailored toward heavy-duty applications (including great soot handling) to begin with and certainly should be the preferred oil for large diesel engines (soot-coughing monsters) and perhaps even smaller diesel engines.

The cost of the 5W-40s will be less though, due to their cheaper base oil. Again, they are more tailored toward diesels (not that they wouldn't work in gas engines). 0W-40s are more tailored toward gas and some small diesel engines.

The site that was mentioned is a Russian site, not a German site, and I linked it above. They did a test to simulate the "hot-tube test," which is the standard test for testing an oil for performance in a turbocharger-equipped engine (the Honda/Acura HTO-06 test etc.). The hot-tube test is the most demanding high-temperature test for an oil, which is needed to ensure protection in the extremely demanding turbo-engine applications.

You can't tell the base oil from the bottle or anything else. It's a trade secret. From the bottle, you can only tell if it's purely Group III or above (full synthetic), Group II+ or below (conventional), or a mix of the two (synthetic blend).

Mobil 1 0W-40 is very likely a combination of Group III+, IV, and V. 5W-40 HDEOs are very likely purely Group III (with no Group III+, IV, or V).