0W-20 vs 5W-30 synthetics in cold temps

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It gets down below -30f here every year. I have 0w oil in the vehicles by then minus tractors ect…. It makes a difference below 0f. When it gets below -30f everything is affected, you can really hear it in your shocks.
 
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I have two jugs in my stash right now.

One SuperTech 0W-20 HM, and one Pennzoil Platinum 5W-30 HM.

Engine is a Honda 3.5 V6. Burns a bit of oil, maybe 6/10ths of a quart every 3,000 miles. Car calls for 5W-20.

Mileage is approaching 150,000. I'd like to start running 30 weights for film strength, but with the cold weather almost here (coldest mornings for me are about -10 degrees F. Not crazy cold, but still cold).

That said, I don't want to run the 5W-30 weight in the winter if it's going to induce extra wear as cold start-up over the 0W-20. At those temps though, is there even really a difference in pumpability, or does that really only matter once you start getting to more like -40 degrees with synthetics?
Pennzoil beats Amsoil in cold flow so I’d almost say use the Penn over Supertech. SP is an ok oil but their cold flow loses to either of the two. Unless you’re in -40 degrees I’d add a block heater regardless.
 
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Pennzoil beats Amsoil in cold flow so I’d almost say use the Penn over Supertech. SP is an ok oil but their cold flow loses to either of the two. Unless you’re in -40 degrees I’d add a block heater regardless.
Cold flow has little relevance to ICE starting. It’s about temperature and shear induced gelling near the pickup tube. After that it flows.

And it’s all determined by the winter rating. If one oil has a better rating then it will be pumpable at a lower temperature regardless of the brand.
 

ZeeOSix

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Mileage is approaching 150,000. I'd like to start running 30 weights for film strength, but with the cold weather almost here (coldest mornings for me are about -10 degrees F. Not crazy cold, but still cold).
Per SAE J300, a "5W" rated oil is good to -30C (-22F) ... so you're expected -10F it's still well above the limit. A 10W in J300 has a minimum temperature of -25C (-13F). Those are the absolute minimum temperatures they should be used at. Most car manufacturers will back off some from those minimums, but that's what it is per J300.

BTW, "film strength" has nothing to do with the viscosity. It has to do with the wear protective tribofilm layer on parts from the AF/AW additives in the oil when the MOFT (the film thickness) goes to zero.
 
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cheesepuffs2

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Per SAE J300, a "5W" rated oil is good to -30C (-22F) ... so you're expected -10F it's still well above the limit. A 10W in J300 has a minimum temperature of -25C (-13F). Those are the absolute minimum temperatures they should be used at. Most car manufacturers will back off some from those minimums, but that's what it is per J300.

BTW, "film strength" has nothing to do with the viscosity. It has to do with the wear protective tribofilm layer on parts from the AF/AW additives in the oil when the MOFT (the film thickness) goes to zero.
Does thicker oil not offer more protection from the MOFT going to zero in the first place?
 

ZeeOSix

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Is improved MOFT at high temps via increased viscosity not a thing though?
Of course ... that's why some here opt to go a grade higher than recommended. To add some MOFT headroom for some extra wear protection. MOFT is the only thing that keeps moving parts from rubbing and wearing on each other. The "film strength" is what the protective tribofilm from the AF/AW additives, and that takes over to help reduce wear when the MOFT goes to zero and parts start grinding on each other. I'd rather rely more on film thickness (MOFT) instead of the last defense against wear of the film strength.

Don't worry about MOFT with the "W" rating ... only that you use the correct "W" rating for the cold start-up conditions so the engine can start and adequately pump the oil through the oiling system.
 
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cheesepuffs2

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Of course ... that's why some here opt to go a grade higher than recommended. To add some MOFT headroom for some extra wear protection. MOFT is the only thing that keeps moving parts from rubbing and wearing on each other. The "film strength" is what the protective tribofilm from the AF/AW additives, and that takes over to help reduce wear when the MOFT goes to zero and parts start grinding on each other. I'd rather rely more on film thickness (MOFT) instead of the last defense against wear of the film strength.

Don't worry about MOFT with the "W" rating ... only that you use the correct "W" rating for the cold start-up conditions so the engine can start and adequately pump the oil through the oiling system.
I appreciate the info. I think maybe my point wasn't clear enough because I'm not concerned about MOFT when cold/upon startup. What I'm getting at is essentially "I want to run thicker oil but I want to know that the higher W number of that thicker oil (0W-20 vs 5W-30) isn't going to cause more wear at cold startup that would negate the added hot protection".
 

ZeeOSix

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I appreciate the info. I think maybe my point wasn't clear enough because I'm not concerned about MOFT when cold/upon startup. What I'm getting at is essentially "I want to run thicker oil but I want to know that the higher W number of that thicker oil (0W-20 vs 5W-30) isn't going to cause more wear at cold startup that would negate the added hot protection".
Like mentioned, use a "W" rating that's appropriate for the coldest start-up conditions. I gave info based on J300 in post #51, which says 5W would be usable down to -22F. If -10F is the coldest you expect, then 5W should be fine. But if you're afraid it's not, then use a 0W and sleep well.
 
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