Mobil 1: Odd Recommendation

This story is somewhat related to the discussion of oil weights and vehicle manufacturer recommendations. My father bought a 1956 Studebaker Hawk with a 259 cu in solid lifter engine. Studebaker recommended a straight 30 wt oil. The dealer recommended 30 wt non-detergent oil. I think that the recommended oil change interval was 2000 miles. From day one my dad used a 20w-20 detergent oil and changed it every 5000 miles. He never had the slightest hiccup from the engine and finally traded the car when he had put 170,000 miles on it. It was using just slightly under a quart between changes at the time. So much for manufacturer's recommendations~!
My Lincoln Town Car has 148,000 miles on the odometer and gets the oil changed every 10,000 miles using Cam-2's 5w-20 synthetic oil. The oil consumption is so small that you can't even measure it.
And for those of you who go to heavier weight oils in the summer, I'd recommend getting a car with an engine cooling system that uses a thermostat~!
 
This story is somewhat related to the discussion of oil weights and vehicle manufacturer recommendations. My father bought a 1956 Studebaker Hawk with a 259 cu in solid lifter engine. Studebaker recommended a straight 30 wt oil. The dealer recommended 30 wt non-detergent oil. I think that the recommended oil change interval was 2000 miles. From day one my dad used a 20w-20 detergent oil and changed it every 5000 miles. He never had the slightest hiccup from the engine and finally traded the car when he had put 170,000 miles on it. It was using just slightly under a quart between changes at the time. So much for manufacturer's recommendations~!
My Lincoln Town Car has 148,000 miles on the odometer and gets the oil changed every 10,000 miles using Cam-2's 5w-20 synthetic oil. The oil consumption is so small that you can't even measure it.
And for those of you who go to heavier weight oils in the summer, I'd recommend getting a car with an engine cooling system that uses a thermostat~!

It's not the fact that it's a 20 grade that I find odd. It's the fact that Mobil recommended an oil designed to meet European Car Makers and ACEA specs rather than the specified Honda USA ILSAC Specs. They have a whole catalog full oils that actually meet the spec. Recommending AFE 0W-20 instead of ESP X2 0W-20 would have been what I expected.
 
I have always taken the website recommendation with a bit of salt. Mobil should concentrate on making their website easier to use. As Steve Jobs would say, three steps should get you what you want. Mobil misses that by a mile.

Example; on the front page you pick your region and a sub menu comes up and you pick North America motor oils in English. Sounds great until you get to the next page and have to tell them all the info again.
 
No it doesn't. Do you ever read the replies people make to you on this?
Now that this thread is dead, perhaps I can ask something off topic, why do you say a 0w oil does not flow better at cold start than a 5w oil? Can you point me to any info sources? I always thought, in general, a 0w oil has lower viscosity when cold than a 5w oil, and will take less force to pump.
 
Now that this thread is dead, perhaps I can ask something off topic, why do you say a 0w oil does not flow better at cold start than a 5w oil? Can you point me to any info sources? I always thought, in general, a 0w oil has lower viscosity when cold than a 5w oil, and will take less force to pump.
First the winter rating isn’t really about flow since if the oil can be pumped it will flow. It’s about cranking and pumpability, the only flow that really matters is in the pan that it doesn’t gel under shear as it’s being drawn into the pickup tube. This causes cavitation and rapid failure.

And it’s completely dependent on temperature. The winter ratings are obtained at different temperatures, so no oil is guaranteed to be thinner except at the temperature for which it is measured. What it means is that above the temperature where a 0W rating is obtained there is no guarantee any oil is thinner than a similar oil with a 5W rating (except that an oil must be labeled for the most favorable winter rating it achieves). This is seen in several brands. “Cold” is relative and for this it means very cold.

Lots of discussion about this here and elsewhere if you choose to look for it.
 
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First the winter rating isn’t really about flow since if the oil can be pumped it will flow. It’s about cranking and pumpability, the only flow that really matters is in the pan that it doesn’t gel under shear as it’s being drawn into the pickup tube. This causes cavitation and rapid failure.

And it’s completely dependent on temperature. The winter ratings are obtained at different temperatures, so no oil is guaranteed to be thinner except at the temperature for which it is measured. What it means is that above the temperature where a 0W rating is obtained there is no guarantee any oil is thinner than a similar oil with a 5W rating (except that an oil must be labeled for the most favorable winter rating it achieves). This is seen in several brands. “Cold” is relative and for this it means very cold.

Lots of discussion about this here and elsewhere if you choose to look for it.
I think when people say ''flow'' they are colloquially referring to pumpability, or the amount of energy needed to move a certain volume over x amount of time, at least that's what I think. Also, if your ambient temp is extremely cold, near the temps at which a 0w oil must qualify, is it still unresonable to generalize that a 0w will ''flow/pump'' easier and or faster than a 5w? You can generalize that it will be thicker right? I'll have to search for those threads, I imagine they are getting more specific comparing one oil to another rather than making a general statement with caveats.
 
Now that this thread is dead, perhaps I can ask something off topic, why do you say a 0w oil does not flow better at cold start than a 5w oil? Can you point me to any info sources? I always thought, in general, a 0w oil has lower viscosity when cold than a 5w oil, and will take less force to pump.
You have to get down near where these limits are tested for in order for it to really matter. A 0W-40 will be more viscous than a 5W-20 down until you get near where the Winter grade for 5W-xx is measured. Around that point, the 5W-20 viscosity will dramatically increase as wax crystal formation happens, while the 0W-40 won't experience that until at least 5C lower.

If the oil can get up the pick-up tube (that's what MRV tests for), "flow" with a PD oil pump is essentially the same, whether the oil is a 0W-xx or 5W-xx. If the relief on the pump is engaged, this is where things change, as a less viscous oil will be less likely to engage the relief.
 
You have to get down near where these limits are tested for in order for it to really matter. A 0W-40 will be more viscous than a 5W-20 down until you get near where the Winter grade for 5W-xx is measured. Around that point, the 5W-20 viscosity will dramatically increase as wax crystal formation happens, while the 0W-40 won't experience that until at least 5C lower.

If the oil can get up the pick-up tube (that's what MRV tests for), "flow" with a PD oil pump is essentially the same, whether the oil is a 0W-xx or 5W-xx. If the relief on the pump is engaged, this is where things change, as a less viscous oil will be less likely to engage the relief.
The original comment was 0w-20 vs 5w-20 and that the 0w ''flows'' easier. You are using an example of a 0w-40 compared to a 5w-20 although I get your point that the viscosity curves cross at some point and it sounds like where they cross can be quite a steep curve. I am curious why your comment was outright that a 0w-20 does not flow as well as a 5w-20 at cold temps. I believe you said ''no it doesn't''. Are you saying this in a general sense or do you mean that there are only specific examples that support your point? I understand what you mean about a PD oil pump though and I do wonder at what point the relief valve opens. Where I am, I see below zero and I always thought a 0w weight is desirable for days when I forget to plug in my engine heater.
 
You can safely use 0w20. 0w20 is better than 5w20 when the engine is cold because it flows quicker when you start the engine.
Sure, when it’s -25*F the 0w may flow slightly better. Anything north of 0*F there’s literally no difference between the two. 0wXX oils will generally have slightly better base oils, but will also have more VIIs, so those two things kinda wash out. ESP is a solid oil, though, and I’d use it without hesitation if the price was right.
 
The original comment was 0w-20 vs 5w-20 and that the 0w ''flows'' easier. You are using an example of a 0w-40 compared to a 5w-20 although I get your point that the viscosity curves cross at some point and it sounds like where they cross can be quite a steep curve. I am curious why your comment was outright that a 0w-20 does not flow as well as a 5w-20 at cold temps. I believe you said ''no it doesn't''. Are you saying this in a general sense or do you mean that there are only specific examples that support your point? I understand what you mean about a PD oil pump though and I do wonder at what point the relief valve opens. Where I am, I see below zero and I always thought a 0w weight is desirable for days when I forget to plug in my engine heater.
The comment was:
You can safely use 0w20. 0w20 is better than 5w20 when the engine is cold because it flows quicker when you start the engine.

Which is inaccurate. If the engine is "cold", but it's 20C or 10C, that's different than it actually being cold ambient-wise. Even when it's actually cold, like 0C, -10C, -15C...etc the 0W-20 isn't going to flow any quicker due to the pump being PD and both oils making it up the pickup in basically the same amount of time.

Within the acceptable use range for the 5W-xx Winter grade, with a bit of a fudge factor (oils are allowed to slip a Winter grade in service), there is effectively no difference unless the pump is going on the relief.

Once we get down toward where you should be using a 0W-xx, then there's obviously a difference, that's why we have different Winter grades.
 
The comment was:


Which is inaccurate. If the engine is "cold", but it's 20C or 10C, that's different than it actually being cold ambient-wise. Even when it's actually cold, like 0C, -10C, -15C...etc the 0W-20 isn't going to flow any quicker due to the pump being PD and both oils making it up the pickup in basically the same amount of time.

Within the acceptable use range for the 5W-xx Winter grade, with a bit of a fudge factor (oils are allowed to slip a Winter grade in service), there is effectively no difference unless the pump is going on the relief.

Once we get down toward where you should be using a 0W-xx, then there's obviously a difference, that's why we have different Winter grades.
Thank you for the clarification. I see the importance of people clarifying what they mean by "cold' and see your point about the PD pump. I guess In my mind, where I am from, "cold" doesn't even start untill -15c and I, based on no actual data, suspect some oils/pumps on some cars will go into bypass due to increased cold viscosity. Do you have any data or sources/studies regarding when common oil pumps will go into bypass on common oil viscosities/oil temps? It would be interesting to see at what temp/oil viscocity common engines/pumps go into bypass as that would potentially allow for clarity on making a general statement about the advantage or lack thereof of a 0w oil vs 5w oil.
 
I think when people say ''flow'' they are colloquially referring to pumpability, or the amount of energy needed to move a certain volume over x amount of time, at least that's what I think. Also, if your ambient temp is extremely cold, near the temps at which a 0w oil must qualify, is it still unresonable to generalize that a 0w will ''flow/pump'' easier and or faster than a 5w? You can generalize that it will be thicker right? I'll have to search for those threads, I imagine they are getting more specific comparing one oil to another rather than making a general statement with caveats.
Perhaps they are but in this instance as it relates to the winter rating, pumpability is a binary not a continuum. Either it will or it won't, and that is what the rating is designed to indicate because the issue is shear-induced gelling near the pump pickup. If it is not pumpable then the engine will fail. If it pumps then it won't.

This is quite the academic exercise, can you explain how your series of questions relate to ICE operation? A pump going into bypass is transient and largely irrelevant since the oil heats up rapidly (and the thicker it is the faster it heats). Your questions asking for how often a generic pump goes into bypass for each winter rating is not answerable nor do I completely understand the rationale.
 
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Perhaps they are but in this instance as it relates to the winter rating, pumpability is a binary not a continuum. Either it will or it won't, and that is what the rating is designed to indicate because the issue is shear-induced gelling near the pump pickup. If it is not pumpable then the engine will fail. If it pumps then it won't.

This is quite the academic exercise, can you explain how your series of questions relate to ICE operation? A pump going into bypass is transient and largely irrelevant since the oil heats up rapidly (and the thicker it is the faster it heats). Your questions asking for how often a generic pump goes into bypass for each winter rating is not answerable nor do I completely understand the rationale.
I am under the assumption that a pump going into bypass during an extreme cold start is not entirely irrelevant, but I am still learning. If it is irrelevant like you say, than that would largely answer things for me.

What I was getting at is, in extreme cold, I am curious how a typical 5w vs a typical 0w oil relates to the duration of a typical pump on a typical engine going into bypass. I understand I would need to get much more specific with all aspects of that question, but in general it seems that in extreme cold (-15c, or perhaps well below) that a typical 0w oil, in general, will cause a pump to be in bypass for a shorter period of time than a typical 5w oil, and less time spent in bypass seems desirable. Therefore in extreme cold a 0w may have some slight benefit over a 5w, but if like you say, being in bypass for a min or two is not relevant that I guess that settles it.

Also, I think there was a graphic posted by someone that showed oil flow volumes to various parts of the engine when the pump is in bypass but I can't find it. Do you happen to know what I can search for or have a link to that graphic?
 
I am under the assumption that a pump going into bypass during an extreme cold start is not entirely irrelevant, but I am still learning. If it is irrelevant like you say, than that would largely answer things for me.

What I was getting at is, in extreme cold, I am curious how a typical 5w vs a typical 0w oil relates to the duration of a typical pump on a typical engine going into bypass. I understand I would need to get much more specific with all aspects of that question, but in general it seems that in extreme cold (-15c, or perhaps well below) that a typical 0w oil, in general, will cause a pump to be in bypass for a shorter period of time than a typical 5w oil, and less time spent in bypass seems desirable. Therefore in extreme cold a 0w may have some slight benefit over a 5w, but if like you say, being in bypass for a min or two is not relevant that I guess that settles it.

Also, I think there was a graphic posted by someone that showed oil flow volumes to various parts of the engine when the pump is in bypass but I can't find it. Do you happen to know what I can search for or have a link to that graphic?
There is no "typical", it's dependent on:
- What the relief pressure is set to on the pump. This varies wildly by manufacturer
- What's upstream of the pump (the engine) and what that resistance looks like
Here's my SRT, Ravenol SSL 0W-40 in it at the time, -14C. Relief on the pump is 65psi, the relief opens. This is a 6.4L V8 with a pretty high volume pump.

 
There is no "typical", it's dependent on:
- What the relief pressure is set to on the pump. This varies wildly by manufacturer
- What's upstream of the pump (the engine) and what that resistance looks like
Here's my SRT, Ravenol SSL 0W-40 in it at the time, -14C. Relief on the pump is 65psi, the relief opens. This is a 6.4L V8 with a pretty high volume pump.


What I am trying to get at is, in theory as I understand it, most 0w oils are thinner than most 5w oils at very cold temps like -10 etc, and therefore seem less likely to keep the pump in bypass quite as long as a 5w. Is this wrong or is it wrong to make such a generalization knowing that there are exceptions? I have seen a few detailed viscosity/temp curves and they are smooth enough that it would seem you could make generalizations even when given only 2 temperature data points.

Additional question - do you agree with the idea that on very cold starts, it is inconsequential that a pump goes into bypass for a min here or there?
 
What I am trying to get at is, in theory as I understand it, most 0w oils are thinner than most 5w oils at very cold temps like -10 etc, and therefore seem less likely to keep the pump in bypass quite as long as a 5w. Is this wrong or is it wrong to make such a generalization knowing that there are exceptions? I have seen a few detailed viscosity/temp curves and they are smooth enough that it would seem you could make generalizations even when given only 2 temperature data points.

Additional question - do you agree with the idea that on very cold starts, it is inconsequential that a pump goes into bypass for a min here or there?
You keep saying that but it's not correct, -10 is nowhere near where the split takes place. At the qualification temperature for a 0W oil an oil that passes is guaranteed to be pumpable whereas an oil that only meets the requirements for a 5W will not be guaranteed. No exceptions. You're also using the word "most" which also is not correct, either the oil passes or it does not. Above the qualification temperature there is no guarantee that any oil will be thinner or thicker than another oil of the same grade.

I'd still like to understand your specific concern here. What are you trying to achieve or accomplish? Are you trying to find some mythical oil with a 5W winter rating that performs as well at -35 as one with a 5W rating?
 
You keep saying that but it's not correct, -10 is nowhere near where the split takes place. At the qualification temperature for a 0W oil an oil that passes is guaranteed to be pumpable whereas an oil that only meets the requirements for a 5W will not be guaranteed. No exceptions. You're also using the word "most" which also is not correct, either the oil passes or it does not. Above the qualification temperature there is no guarantee that any oil will be thinner or thicker than another oil of the same grade.

I'd still like to understand your specific concern here. What are you trying to achieve or accomplish? Are you trying to find some mythical oil with a 5W winter rating that performs as well at -35 as one with a 5W rating?
Like most on here, I am simply trying to better understand motor oil and their specifications. The concept that its common for a 5w to be thinner than a 0w at temperatures that most would consider quite cold is new to me, and I am trying to learn more about it. When you say ''the split'' what do you mean?

I do understand that above the qualification temperature there is no ''guarantee'' that any oil will be thinner or thicker than any other but I previously thought you could make that generalization but it seems I cannot. Can you point me to any detailed viscosity vs temperature curves, or any data showing that say, a particular 5w is thinner than a 0w at a fairly cold temps? I am curious how common this is.
 
That data isn’t published, partly because it’s not relevant to operation. Any differences would be small and may or may not be within the repeatability of the test. It simply does not matter in operation since the winter rating is achieved at a specific temperature and it isn’t about what random oil may be somewhat thinner or thicker in the gap between the testing temperatures. Again if the oil pumps it will flow and will rapidly heat up under shear. The interstitial isn’t relevant to pumping.

One thing you’re correct about is that you can’t make the generalization you’re making.
 
That data isn’t published, partly because it’s not relevant to operation. Any differences would be small and may or may not be within the repeatability of the test. It simply does not matter in operation since the winter rating is achieved at a specific temperature and it isn’t about what random oil may be somewhat thinner or thicker in the gap between the testing temperatures. Again if the oil pumps it will flow and will rapidly heat up under shear. The interstitial isn’t relevant to pumping.

One thing you’re correct about is that you can’t make the generalization you’re making.

I understand your point and you got me thinking which is great, and I appreciate your thoughts, I am just stubborn enough to need data to overturn a long held belief. I do understand what you mean by ''cross over'' and separately, I get the idea that a PD pump will, well, pump, regardless of viscosity (to a point).

Having said that. if detailed data for very cold viscosity curves isn't published, we then can't say one way or the other regarding the applicability of general statements which I think speaks to both out thoughts. Most detailed viscosity curves I have seen that show any cross over at all show said cross over as occurring at temps above 0c (which does support my thoughts). Here for example is a very subtle (and rather meaningless) cross over and it looks like it occurs around 5c https://www.widman.biz/English/Tables/Graph-motors_files/ns_Entre_0_y_30C.html?TB_iframe=true

Unless someone has data I think we can let this thread die.
 
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