Is Mobil 1 0w-40 too thin?

[scrllock]

Castrol Euro 5w40 held up longer than m1 0w40 in the Audi 3.0t sc. The 1.4tsi took 5w40 as well. The 2.0t looks to fit right in the middle of the VW line up lol, you see a pattern here? The 5w40 will do well to absorb the turbo heat, viscosity is king, just change it every 4-5k. Oil pressure should be better too.
Also, I could have swore there was an article about how vw504 oil, which is very good oil, does not do well with ethanol. With Europe not mixing ethanol in their gasoline/petrol like we do. Anyone else confirm or deny? But right now the jetta has valvoline xl-iii euro 5w30 in the 1.4tsi, it's vw504 and came with 2 car washes at the express lube. Will have an oil analysis in a few months, 250,000km coming up.

the only thing is that 504 is low-mid saps, so lower TBN to handle acid byproducts from ethanol combustion. nothing inherently bad about using ethanol, many 504 lubes are API SN/SP which has tests for e85. i would change oil earlier if using ethanol, but this isn't specific to 504.

 

[edyvw]

the only thing is that 504 is low-mid saps, so lower TBN to handle acid byproducts from ethanol combustion. nothing inherently bad about using ethanol, many 504 lubes are API SN/SP which has tests for e85. i would change oil earlier if using ethanol, but this isn't specific to 504.

Not necessarily. Amsoil 5W30 AEL (VW504.00) has TBN almost 9, which is in line with full-SAPS oils. The question is are additives ash ones or ashless.

 

[altaylar]

Thus the move to 40 grade. Perhaps you missed that part. Then again the motor is tune only. I guess that tune allows more fuel past the rings...

https://upload.wikimedia.org/wikipedia/commons/6/63/Vapor_ethanol_mixtures_Fig_4.3.jpg


It would take longer to get up to temperature? I didn't recall grade being a measure of specific heat.

If you think about the change in temperature being a function of hest intake divided by spesific heat, and heat intake as a function of some friction coefficient and distance traveled by the oil it will make sense. We could say that thicker oil should have more carbon per molecule, but first i do not know how that effects the spesific hest either, second there are various sort of base oils that this would be an oversimplification. But thicker oil flows slower all things equal, especially when cold.

 

[scrllock]

Not necessarily. Amsoil 5W30 AEL (VW504.00) has TBN almost 9, which is in line with full-SAPS oils. The question is are additives ash ones or ashless.

Is that why it doesn't actually have 504 approval?

 

[edyvw]

Is that why it doesn't actually have 504 approval?

Actually, AEL had VW504.00 approval until, as far as I remember, last year. But Amsoil decided not to renew approvals for any of their oils.

VW 504.00 has only limit on minimum TBN (starting with 2020 update. Before it didn’t have. And minimum limit is 7), and on max Sulfated Ash and Phosphorus. And it is quite high, 1% (older versions of VW504.00 had SA at 1.5%) and phosphorus 0.9%. That means even some full SAPS oils can meet that (especially older versions of VW504.00). However, emissions treatment compatibility is strict, and no full SAPS oil can meet that. Therefore, to meet emissions equipment demands, it has to be oil with ashless additives. That doesn’t mean TBN is low. On contrary, since 2020 VW specifically says minimum TBN is 7.

 

[johnmyster]

If you think about the change in temperature being a function of hest intake divided by spesific heat, and heat intake as a function of some friction coefficient and distance traveled by the oil it will make sense. We could say that thicker oil should have more carbon per molecule, but first i do not know how that effects the spesific hest either, second there are various sort of base oils that this would be an oversimplification. But thicker oil flows slower all things equal, especially when cold.

I love it when internet scientist theorists speculate that viscosity delta of one or two grades impacts heating rate of seven pounds of oil in the context of hundreds of pounds of steel…or other alloys.

 

[altaylar]

I love it when internet scientist theorists speculate that viscosity delta of one or two grades impacts heating rate of seven pounds of oil in the context of hundreds of pounds of steel…or other alloys.

I know, right? I always wanted to be a scientist but I was too dumb as a kid to get into a college. And Its not like you could verify it empirically by running thicker oil.

Jokes aside, thicker oil tends to increase its temperature slower, but reach higher temperature in equilibrium as well as peak. If you talk with people who take their car to race track, you will find that most of us increased their viscosity by one or two grades, but we all will complain how long it takes now for the oil to get up to temp, so it hurts our heart when we do short trips with our car.

I have a gr86 that calls 0w20 on its manual, and I used to track it with 5w30. Now that I am intermediate and I am seeing higher temperatures (around 260-270f peak), I moved it up to 0w40 and I can definitely tell you that there is a noticable difference how long it takes to reach 212f.

 

[johnmyster]

I know, right? I always wanted to be a scientist but I was too dumb as a kid to get into a college. And Its not like you could verify it empirically by running thicker oil.

Jokes aside, thicker oil tends to increase its temperature slower, but reach higher temperature in equilibrium as well as peak. If you talk with people who take their car to race track, you will find that most of us increased their viscosity by one or two grades, but we all will complain how long it takes now for the oil to get up to temp, so it hurts our heart when we do short trips with our car.

I have a gr86 that calls 0w20 on its manual, and I used to track it with 5w30. Now that I am intermediate and I am seeing higher temperatures (around 260-270f peak), I moved it up to 0w40 and I can definitely tell you that there is a noticable difference how long it takes to reach 212f.

Zee06 will be along shortly to remind you that the thicker oil doesn’t circulate slower because the oil pump is PD. So the impact of viscosity on slower heating can only be from a delta on specific heat, which is negligible.

And even if it circulated slower, how would that matter? It just means the oil in contact with the hot parts would be heated more. Heat energy is still heat energy headed for the oil pan.

But what do I know? I tow with a truck that counts on oil jets to keep the pistons from melting and has an oil cooler the size of a canned ham.

 

[altaylar]

Zee06 will be along shortly to remind you that the thicker oil doesn’t circulate slower because the oil pump is PD. So the impact of viscosity on slower heating can only be from a delta on specific heat, which is negligible.

But what do I know? I tow with a truck that counts on oil jets to keep the pistons from melting and has an oil cooler the size of a canned ham.

Im glad there are members like you who corrects our mistakes.

Would you also say thicker oil does not increase the pressure? Because I am also under the impression that if it does, and there was this dude called Bernoulli that might have found a negative relationship between a fluid's speed and pressure

Seriously though, I am a mechanical engineer, and I am quite surprised how factually wrong a significant amount of comments on this forum. I used to believe older members with more posts might have been better educated, but I am seeing that there is an echo chamber effect going on with misinformation

 

[kschachn]

Seriously though, I am a mechanical engineer, and I am quite surprised how factually wrong a significant amount of comments on this forum. I used to believe older members with more posts might have been better educated, but I am seeing that there is an echo chamber effect going on with misinformation

Like when you said a monograde oil can be shear cleaved in an engine? You sure didn’t understand the difference in shear heating and permanent viscosity loss due to a reduction in carbon chain length.

 

[OVERKILL]

Im glad there are members like you who corrects our mistakes.

Would you also say thicker oil does not increase the pressure? Because I am also under the impression that if it does, and there was this dude called Bernoulli that might have found a negative relationship between a fluid's speed and pressure

Seriously though, I am a mechanical engineer, and I am quite surprised how factually wrong a significant amount of comments on this forum. I used to believe older members with more posts might have been better educated, but I am seeing that there is an echo chamber effect going on with misinformation

If you feel there is misinformation being presented, please take the time to address it.

Most oil pumps are positive displacement, which means that, as long as the relief is not engaged, the same volume of oil is being displaced per revolution regardless of the viscosity. There are some minor caveats, like pump slip with thinner oils, which results in a slight reduction in volume moved, but assuming a perfect pump, a PV pump doesn't care what the viscosity is. Yes, as you touched-on, this means that there's an increase in pressure in order for that volume to remain the same with the heavier viscosity fluid.

 

[altaylar]

Like when you said a monograde oil can be shear cleaved in an engine? You sure didn’t understand the difference in shear heating and permanent viscosity loss due to a reduction in carbon chain length.

Did you take the time to go through my older posts. I feel important now.

And yes, viscosity of any oil, including monograde, can change permanently with heat and mechanical stress. I think the former is easier to understand so lets focus on that. There are 3 mechanisms i can think of, oxidation, thermal cracking, and volatilization, the second one decreasing the viscosity while the first and the last one increasing. Volatilization it was more a deal back in Base 1 oil days. I am not 100% sure of this, but I think volatilization does not have a significant impact in any engine oil you would buy today, beyond the secondary effects through the shorter carbon chains created by the former mechanism. Its been decade since I last learned about these things though. Probably chatgpt could answer your questions better on this. But thermal cracking is also how refiniers break longer chains into smaller ones.

But i am not sure what is the issue there. Do you think you could run a monograde oil forever without any change in viscosity?

 

[altaylar]

If you feel there is misinformation being presented, please take the time to address it.

Most oil pumps are positive displacement, which means that, as long as the relief is not engaged, the same volume of oil is being displaced per revolution regardless of the viscosity. There are some minor caveats, like pump slip with thinner oils, which results in a slight reduction in volume moved, but assuming a perfect pump, a PV pump doesn't care what the viscosity is. Yes, as you touched-on, this means that there's an increase in pressure in order for that volume to remain the same with the heavier viscosity fluid.

That’s true for an ideal PD pump before the relief valve opens — it displaces about the same volume per rev regardless of grade with thin oil having a little more slip.

But in a real engine, thicker oil builds pressure faster, opens the relief sooner, and more flow gets bypassed back to the sump instead of going through the engine, and these effects are even stronger while the oil is cold, making it take even longer to reach the temperature which was the begining of this debate.

Thicker also moves slower through clearances (even without a bypass, there is a differential effect of viscosity on different clearance dimensions), so less oil reaches some parts per unit time, and suction losses or aeration can limit delivery when cold. So viscosity absolutely affects how much oil actually circulates in the engine, even if pump displacement is constant.

 

[StarCaller]

That’s true for an ideal PD pump before the relief valve opens — it displaces about the same volume per rev regardless of grade with thin oil having a little more slip.

But in a real engine, thicker oil builds pressure faster, opens the relief sooner, and more flow gets bypassed back to the sump instead of going through the engine, and these effects are even stronger while the oil is cold, making it take even longer to reach the temperature which was the begining of this debate.

Thicker also moves slower through clearances (even without a bypass, there is a differential effect of viscosity on different clearance dimensions), so less oil reaches some parts per unit time, and suction losses or aeration can limit delivery when cold. So viscosity absolutely affects how much oil actually circulates in the engine, even if pump displacement is constant.

Thermal cracking usually increases volatility /

 

[altaylar]

Thermal cracking usually increases volatility /

Thanks! I was supposed to say "viscosity" not volatility. Edited my previous post, and i should definitely be more careful typing from my phone. I appreciate you pointing it out, and you sre absolutely correct

 

[edyvw]

Like when you said a monograde oil can be shear cleaved in an engine? You sure didn’t understand the difference in shear heating and permanent viscosity loss due to a reduction in carbon chain length.

I am still waiting more wisdom on approvals.

 

[chris719]

That’s true for an ideal PD pump before the relief valve opens — it displaces about the same volume per rev regardless of grade with thin oil having a little more slip.

But in a real engine, thicker oil builds pressure faster, opens the relief sooner, and more flow gets bypassed back to the sump instead of going through the engine, and these effects are even stronger while the oil is cold, making it take even longer to reach the temperature which was the begining of this debate.

Thicker also moves slower through clearances (even without a bypass, there is a differential effect of viscosity on different clearance dimensions), so less oil reaches some parts per unit time, and suction losses or aeration can limit delivery when cold. So viscosity absolutely affects how much oil actually circulates in the engine, even if pump displacement is constant.

All technically true but not really relevant. My oil temps don't take notably longer to reach 100C with 0W-40 than with 0W-20 on my Mazda, it is dominated by ambient conditions. My BMW Z4M with 10W-60 takes less time to reach 100C than my M2 comp did with 0W-30 FE oil. I also noticed no difference between 3.0 HTHS 0W-30 and 3.6 HTHS 0W-40 in the M2.

 

[edyvw]

All technically true but not really relevant. My oil temps don't take notably longer to reach 100C with 0W-40 than with 0W-20 on my Mazda, it is dominated by ambient conditions. My BMW Z4M with 10W-60 takes less time to reach 100C than my M2 comp did with 0W-30 FE oil. I also noticed no difference between 3.0 HTHS 0W-30 and 3.6 HTHS 0W-40 in the M2.

Technically thicker oil will create more resistance and with that more heat. However, differences are minuscule to notice on oil gauge. Then there are always too many other variables like ambient temperature, traffic etc. to notice something like that. I had in BMW all kind of oils on street and track, from 105f to -42f ambient temperature etc. and can’t definitely say which one reaches operating temperature faster.

 

[4WD]

Thermal cracking usually increases volatility /

300-400C+ in a refinery …

 

[OVERKILL]

That’s true for an ideal PD pump before the relief valve opens — it displaces about the same volume per rev regardless of grade with thin oil having a little more slip.

OK, we are on the same page there.

But in a real engine, thicker oil builds pressure faster, opens the relief sooner, and more flow gets bypassed back to the sump instead of going through the engine, and these effects are even stronger while the oil is cold, making it take even longer to reach the temperature which was the begining of this debate.

Which real engine are we talking about though? And how cold? This is all wildly application dependent. Also, many applications (like both my HEMI's) have heat exchangers that work to increase the rate at which the oil is heated, while also limiting the temperature that the oil can reach.

Thicker also moves slower through clearances (even without a bypass, there is a differential effect of viscosity on different clearance dimensions), so less oil reaches some parts per unit time, and suction losses or aeration can limit delivery when cold. So viscosity absolutely affects how much oil actually circulates in the engine, even if pump displacement is constant.

If the oil is leaving the pump, it's in circulation. Things like rod bearings will draw less heavier oil from the galleries, because they need less of it. So again, assuming the pump is not on the relief, certain clearances will just experience higher pressure for the same amount of flow, which we see in the difference in pressure observed at the gallery right after the pump. But again, this is predicated on the pump not being on the relief. If the relief opens, then we have less volume in circulation, but as I noted, this is very application dependent, and there are some engines now, like the Pentastar, that don't use a conventional PD pump, but I think for the sake of this discussion, we keep it focused on PD pumps and behaviour of the system relative to that.

As @johnmyster noted, this is a pet subject for @ZeeOSix, so I'm a bit surprised he's not in here already, lol. @Shannow has written some considerable material here on bearing design and lubrication as well, though not in more recent years, as he spends less time on the forum than he used to.