What is the best oil ingredient to protect against cold start wear?

[OVERKILL]

Could not the same be said of a 5W-20?

(The logic being the base stock has no choice but to be something very good in order to be so thin, perhaps the same with 0W-20 if I now think about it. High % of synthetic even if "conventional" oil no matter the brand or type?)

0w-20 you are closer to the mark, but both can be blended easily with Group III. The 5w-20 winter designation is an easier target with a cheaper base because of the relatively narrow spread, same reason it is cheap to blend a 10w-30.

Also, the Noack limits for GF-5 and the like are not low. There's no equivalent of Porsche A40 for your typical SN GF-5 5w-20 or 0w-20 and they of course have to fall within the Zinc/Phos limits for your traditional SN grades, whereas 40's are exempt, so you get higher levels of AW additives too.

I am presently running a 0W, I chose Castrol. I wonder if I should run a 5W, maybe Mobil 1 when winter hits, not sure the flow on my 0W oil (Castrol Edge) is great. It may be good, but, can I do better?

Looking specifically at the Mobil product portfolio, the 0w-xx grades all have higher concentrations of PAO than the 5w-xx ones. So the 0w-xx are the more expensive oils to blend.

I should add.. cold flow. Perhaps I am overthinking and the 0W (0W-40 Castrol Edge is my present fill) is fine, flows well enough, etc. Or I could choose a better flowing 5W (someone just mentioned Redline, then there is Mobil, Pennzoil/SOPUS which includes QS, a whole slew of oils are 5W.) Many options.. Is it significant for a superior flowing 5W to a 0W which may not flow cold as well, remember oil in a pan is like Jell-O sucked through a straw going up, or is this not exactly worth obsessing over?

Not sure what you are saying? As long as both oils are pumpable, there's really not going to be any difference in flow until you start to approach the limits of the Winter rating, at which point the 0w-xx has a marked advantage.

I am happy we are touching on that just because an oil is 0W, a 5W may be better, almost superior, in cold flow. I feel some do not know this.

That goes against the very premise of the Winter rating system which is predicated on performance in two key areas: The oil's impact on cranking speed (CCS) and the oil's ability to be pumped. A 0w-xx has to meet more stringent standards for both of these metrics even if, due to having a higher 100C visc, it's a a more viscous lube at temperatures where those factors don't come into play. At those temperatures, either oil is going to flow just fine, because lubrication is pressurized and oil pumps are positive displacement. About the only artifact you are going to see is higher oil pressure.

GC 0W-30 seems to get knocked for being another poor cold flowing 0W oil.. Castrol again. Thicker oils as well, I wonder if that impacts on their poorer cold performance. They say 0W.

Mobil 1 on the other hand, let's say 0W-40 for example, I wonder it's cold flow performance, including vs a 5W.. Interesting.

GC 0w-30 passes the same CCS and MRV requirements as any other 0w-xx lube. It will be inherently more viscous than a lighter oil like M1 EP 0w-20 for example, but it will perform as required.

 

[JT20]

0w-20 you are closer to the mark, but both can be blended easily with Group III. The 5w-20 winter designation is an easier target with a cheaper base because of the relatively narrow spread, same reason it is cheap to blend a 10w-30.

Also, the Noack limits for GF-5 and the like are not low. There's no equivalent of Porsche A40 for your typical SN GF-5 5w-20 or 0w-20 and they of course have to fall within the Zinc/Phos limits for your traditional SN grades, whereas 40's are exempt, so you get higher levels of AW additives too.



Looking specifically at the Mobil product portfolio, the 0w-xx grades all have higher concentrations of PAO than the 5w-xx ones. So the 0w-xx are the more expensive oils to blend.



Not sure what you are saying? As long as both oils are pumpable, there's really not going to be any difference in flow until you start to approach the limits of the Winter rating, at which point the 0w-xx has a marked advantage.



That goes against the very premise of the Winter rating system which is predicated on performance in two key areas: The oil's impact on cranking speed (CCS) and the oil's ability to be pumped. A 0w-xx has to meet more stringent standards for both of these metrics even if, due to having a higher 100C visc, it's a a more viscous lube at temperatures where those factors don't come into play. At those temperatures, either oil is going to flow just fine, because lubrication is pressurized and oil pumps are positive displacement. About the only artifact you are going to see is higher oil pressure.



GC 0w-30 passes the same CCS and MRV requirements as any other 0w-xx lube. It will be inherently more viscous than a lighter oil like M1 EP 0w-20 for example, but it will perform as required.

Thank you for your expert info and clarifications.

I think the only thing I still have questions about, is what constitutes cold flow (if that is even a term.) Perhaps.. if a thin 5W (5W-XX) oil would flow better than a 0W (0W-XX) oil. If that statement is correct as written.. it may not be.

The most common comparison I've seen is to 5W-30 vs 0W-40. I chose Castrol based on recommendation from my car's ownership community. Even then, plenty said just put in the 5W-30 and it was a tough decision. Castrol has both 0W-30 or at least they used to ? and 0W-40 (that's Castrol again meaning from previous) and I have debated switching brand. Mobil 1 5W-30 EP upon AP discontinuation was discussed but I decided to go a different way, that is for my situation. Maybe we can apply some of these things to the conversation about cold flow at hand? This is all great information.

 

[OVERKILL]

The only time you need to worry about "flow" is whether it can get to the oil pump and this can be avoided by choosing an oil with the appropriate Winter rating for your location. Lubrication doesn't happen under gravity, which is why Pour Point was abandoned in favour of CCS and MRV, which more accurately mirror the two parameters we are most interested in:
1. Will the oil pump - most important
2. Will the oil allow the engine to crank over fast enough to start - 2nd most important

At most moderate temperatures where we don't begin to approach the limits of the Winter rating a GF-5 5w-30 will definitely be thinner than a 0w-40, which is blended intentionally to be that way; to carry the xW-40 designation and thus be more viscous at temp. Since viscosity has an inverse relationship with temperature, as the oil cools the 0w-40 stays thicker than the 5w-30. Once wax crystal formation starts to take place the 5w-30 will rapidly increase in thickness whereas the 0w-40 won't, this will begin to happen somewhere around -30C, which is the temperature for which CCS is tested for the 5W-xx designation.

A good rule of thumb is that viscosity roughly doubles for every 5C decrease in temperature and halves for every 5C increase. This works for both CCS and MRV visc figures but those do not directly translate to KV.

Let's take two example oils:
1. Fred's Home 5w-30:
- CCS @ -30C: 5,800cP

2. Rob's Premium 0w-40:
- CCS @ -35C: 5,800cP

At -30C Rob's Premium would be ~2,900cP, half the visc of Fred's Home
At -35C Fred's Home would be ~11,600cP, twice the visc of Rob's Premium and well above the limit of 6,200cP @ -35C for the 0w-xx designation

CCS is almost always where they fail. It's a difficult task to keep volatility low, cold temperature viscosity low enough to pass the specs and prove suitably stable at higher temperatures to pass demanding approval protocols like A40. This is why you often see PAO in these lubes, because it is free of wax and thus doesn't experience wax crystal formation at low temperatures. It's also more oxidatively stable and holds up at higher temperatures better. It's also less volatile.

You change any one of those parameters and it becomes much easier to meet without PAO.

 

[ABN_CBT_ENGR]

I think the only thing I still have questions about, is what constitutes cold flow (if that is even a term.) Perhaps.. if a thin 5W (5W-XX) oil would flow better than a 0W (0W-XX) oil. If that statement is correct as written.. it may not be.

Just adding a data point here as you guys are going along great in the discussion

"cold flow" is a meaningless term EXCEPT in a gravity system, in a pressurized system, flow is flow.

Also, don't get too much into the wax and crystals because when they go through the pump and start down the tube, the physical properties and fluid properties the oil is subjected to generates more than enough heat to mitigate that as well.

Do the math, at about 1 GPM (RPM dependent in an ICE) for the pump with about say 20 ft total for the circuit- the oil has done one turn in slightly under 1 second. Much of this is more urban legend that actual fact.

 

[OVERKILL]

Just adding a data point here as you guys are going along great in the discussion

"cold flow" is a meaningless term EXCEPT in a gravity system, in a pressurized system, flow is flow.

Also, don't get too much into the wax and crystals because when they go through the pump and start down the tube, the physical properties and fluid properties the oil is subjected to generates more than enough heat to mitigate that as well.

Do the math, at about 1 GPM (RPM dependent in an ICE) for the pump with about say 20 ft total for the circuit- the oil has done one turn in slightly under 1 second. Much of this is more urban legend that actual fact.

Yup, the main risk with wax crystal formation is when it's significant enough to prevent the oil from making it into the oil pump/pick-up. As long as it can be pumped, the pressure and shearing of the pump will quickly deal with any of that.

 

[ABN_CBT_ENGR]

Yup, the main risk with wax crystal formation is when it's significant enough to prevent the oil from making it into the oil pump/pick-up.

Honestly, I have done lube projects in Siberia, China, Mongolia and Oil Sands (Ft. McMurray) and never have experienced or heard of that condition being a real world problem. If it ever happened the engine would lock up long before the sump oil warmed enough to flow freely.

I would like to see a documented verifiable incidence where such a thing did happen.

Most of the time in these extreme conditions, the "shake/rattle/roll" has nothing to do with oil flow, it has to do with tolerance shrinking causing grabs and evens out if and when ( with whatever scuffing damage) the part warms.

This is why on many mining drives in extreme temps as well as precision compressors/blowers like IR centacs have to have hours of warm fluid circulating to warm and expand tolerances, not the oil.

 

[OVERKILL]

Honestly, I have done lube projects in Siberia, China, Mongolia and Oil Sands (Ft. McMurray) and never have experienced or heard of that condition being a real world problem. If it ever happened the engine would lock up long before the sump oil warmed enough to flow freely.

I would like to see a documented verifiable incidence where such a thing did happen.

Most of the time in these extreme conditions, the "shake/rattle/roll" has nothing to do with oil flow, it has to do with tolerance shrinking causing grabs and evens out if and when ( with whatever scuffing damage) the part warms.

This is why on many mining drives in extreme temps as well as precision compressors/blowers like IR centacs have to have hours of warm fluid circulating to warm and expand tolerances, not the oil.

It's the basis for the MRV test, the 60,000cP limit was determined to be below where your "typical" engine oil pump was not able to draw the product out of the sump. Now, I recall in one of the documents on it that in testing, the Jeep 4.0L i6 was much more sensitive to this and would fail to pump at something like 45,000cP? It couldn't draw the oil up the pickup.

I can go searching for it if you'd like? It was discussed on here several years back.

 

[kschachn]

This is a good explanation:

http://www.lube-media.com/wp-conten...lating-and-manufacture-of-automotive-oils.pdf

"Two low-temperature tests are employed to define the limits of “W” grades. The first, low-temperature cranking viscosity is measured by ASTM D5293 and has been found to correlate with the ability of an engine to start at low temperatures. The test is run at temperatures between -10 C and -35 C and subjects the oil to a high rate of shearing during testing.

Low-temperature pumping viscosity (ASTM D4684) cools the oil to an even greater degree (-15 C to -40 C) over an extended period of time, designed to allow any wax in the oil to crystalize. Such waxy materials can produce a gel preventing the oil flowing into the oil pump and hence lead to oil starvation in the early stages of operation in winter conditions before the engine and the oil warm up."

 

[kschachn]

Honestly, I have done lube projects in Siberia, China, Mongolia and Oil Sands (Ft. McMurray) and never have experienced or heard of that condition being a real world problem. If it ever happened the engine would lock up long before the sump oil warmed enough to flow freely.

Yes, the engines seized due to oil starvation:

https://www.savantgroup.com/media/SBTDirectCoolPaperV12-SAE2008-01-2481.pdf

 

[JT20]

Question about this, I agree this is a great discussion. Aside from any residual oil on engine parts, if there is any.. Is a good visual example that, perhaps the oil pump pick-up tube is akin to a vacuum cleaner sucking the oil up into it, against gravity, from the initial start of the engine on forward?

I would assume the pick-up tube (that leads to the pump,) is immersed in the oil in the pan, akin to a straw in a soda or milkshake.

The soda or milkshake then travels up the straw to its next destination.

The oil pressure is highest when the oil is cold and the engine is cold and first start, it goes down then the oil gets hotter, so is it really pressurized from the very first seconds?

 

[Silver]

Question about this, I agree this is a great discussion. Aside from any residual oil on engine parts, if there is any.. Is a good visual example that, perhaps the oil pump pick-up tube is akin to a vacuum cleaner sucking the oil up into it, against gravity, from the initial start of the engine on forward?

I would assume the pick-up tube (that leads to the pump,) is immersed in the oil in the pan, akin to a straw in a soda or milkshake.

The soda or milkshake then travels up the straw to its next destination.

The oil pressure is highest when the oil is cold and the engine is cold and first start, it goes down then the oil gets hotter, so is it really pressurized from the very first seconds?

The way I understand it is the pump is going to 'displace' the same amount of oil at the same rate because it's strong enough that viscosity doesn't affect its pump rate.

 

[ABN_CBT_ENGR]

determined to be below where your "typical" engine oil pump was not able to draw

No need, this is an argument I and others have had with peers in SAE many times and there's a lot of politics on the test and among the people.

You hit on it right there. The "typical" engine pump isn't a true PD sealed pump all the way through the suction.

I and others have disproven this "theory" with PD gear pumps that actually DO pull NPSH.

Point is, its a pump issue, not an oil one

Yes, the engines seized due to oil starvation.

Respectfully, show me the alleged test and component and I'll show you the flaw in that logic

 

[OVERKILL]

Point is, its a pump issue, not an oil one

Yes, I agree, which is why I found it interesting that the AMC/Jeep 4.0L was a particularly sensitive case, I assume due to what you've touched-on in your post.

 

[kschachn]

Well you can argue all you wish with the SAE, but in the early 80s there were engine failures in Europe and the USA due to the oil gelling under shear in the vicinity of the oil pump pickup tube. That's why J300 was revised at that time. Whether it was due to some design defect I do not know but it did illustrate a problem with using pour point to predict low-temperature behavior.

If a pocket of air is all that surrounds the pickup screen then you're not going to get any pumping regardless of the pump design.

 

[JT20]

The way I understand it is the pump is going to 'displace' the same amount of oil at the same rate because it's strong enough that viscosity doesn't affect its pump rate.

Ahh. So, if there is no air, which there shouldn't be.. then it will suck up the same amount of oil? Displacing from.. the pump, to the pump, through the tube ? 100% air-free pull of oil.

It makes sense there would not be air if the tube is fully submersed in the oil in the oil pan?

 

[ABN_CBT_ENGR]

Well you can argue all you wish with the SAE, but in the early 80s there were engine failures in Europe and the USA due to the oil gelling under shear in the vicinity of the oil pump pickup tube. That's why J300 was revised at that time. Whether it was due to some design defect I do not know but it did illustrate a problem with using pour point to predict low-temperature behavior.

If a pocket of air is all that surrounds the pickup screen then you're not going to get any pumping regardless of the pump design.

I and others have argued and refuted a number of things over the decades but that's a different issue and not germane to this issue other than to point out that there's a reason many industries will not allow SAE standards to be used.

Back to the subject...


If a pocket of air is surrounding the pick up screen, that's a volume/level issue- not a property of the oil or issue with the pump but I can see some organizations disregarding that in favor of popular group think.

 

[kschachn]

I and others have argued and refuted a number of things over the decades but that's a different issue and not germane to this issue other than to point out that there's a reason many industries will not allow SAE standards to be used.

Back to the subject...

If a pocket of air is surrounding the pick up screen, that's a volume/level issue- not a property of the oil or issue with the pump but I can see some organizations disregarding that in favor of popular group think.

Sure, okay.

 

[ABN_CBT_ENGR]

Ahh. So, if there is no air, which there shouldn't be.. then it will suck up the same amount of oil? Displacing from.. the pump, to the pump, through the tube ? 100% air-free pull of oil.

It makes sense there would not be air if the tube is fully submersed in the oil in the oil pan?

Yes, if you "dead head" the suction on a PD gear pump, even for a full second, it will back drive the NDG and almost self destruct.

So, unless the oil is frozen to the point where it is literally a solid, either it will go in or the pump will destroy itself the first time.

Remember, gear and progressive cavity pumps routinely pump candies, caramels, tar and all kinds of stuff that will make cold oil look like hot water with no difficulties.

 

[ABN_CBT_ENGR]

Sure, okay.

Absolutely, and I respectfully invite you or anyone else to demonstrate otherwise with a real world example

 

[ABN_CBT_ENGR]

It makes sense there would not be air if the tube is fully submersed in the oil in the oil pan?

All pumps have tolerances so without a check valve there will be drain back but the tube should always be fully submerged with a meniscus level inside due to whatever atmospheric pressure is against the bulk sump.

In terms of volume relative to pump speed that volume would be like a single drop coming from a fully open kitchen faucet so it wouldn't be there a fraction of a second.