Flow rates in below "0" degrees dino vs synthetic

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Wisconsin
Pitbull, probably a good spec for you to view is the cold cranking spec ,commonly listed as CCS, cP on the product data sheets. A 10W oil is tested at -25C, 5W at -30C per the ASTM testing procedure. Here are some random CCS ratings for 5W-30 dino & syn oils:
code:
Valvoline All Climate 6300 cP
Mobil Drive Clean     5500 cP
Valvoline SynPower    4700 cP
Citgo Synthetic       3950 cP

The lower cold crank ratings are obviously the choice for sub-zero temps.
 
Thanks Blue99, that was the information I needed, but did not know it. Mobil 1 10w30 supersyn at -25 is 3967 Mobil Drive Clean 5w30 at -25 is 2900 They want an oil to be under 7000 so it won't cause any damage. I wanted to run Mobil 1 10w30 in both my vehicles year round. Since it seldoms gets below "0" where I live and based on these numbers I should be fine running Mobil 1 10w30. Yes it does not have as good of a cold cranking number as a 5w30 at -25 it is way under the magic 7000 number. Plus if it gets below "0" I'm not going to take any of my vehicles out of their heated garage. Being old and retired does have some benefits [Smile] Am I right, that the reason the manufactures recommend 5w30 year round is for fuel economy? It looks like any 10w30 synthetic would do a good job year round in any climate we see in the contiguous United States.
 
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9,448
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Any synthetic 0,3,5,10 W X is going to be have a Cp of less then 7000 at -25. It is almost a no brainer with synthetics. Some dino come awfully close to the limit of 7000 Cp. As a matter of fact so long as my group IV or V synthetic is lower then a 15W I do not even concern myself with Cp unless I expect temps to get colder then -25F. Last year I ran 5W40 Redline all winter includeing a few -18F nights. I have run M1 10W30 down to about -22F before with no problems at all.
 
quote:
Originally posted by JohnBrowning: Any synthetic 0,3,5,10 W X is going to be have a Cp of less then 7000 at -25. It is almost a no brainer with synthetics. Some dino come awfully close to the limit of 7000 Cp. As a matter of fact so long as my group IV or V synthetic is lower then a 15W I do not even concern myself with Cp unless I expect temps to get colder then -25F. Last year I ran 5W40 Redline all winter includeing a few -18F nights. I have run M1 10W30 down to about -22F before with no problems at all.
Then why do people even bother with Mobil 1 5w30 when Mobil 1 10w30 is a better oil and gets better UOA? There is no way the auto manufactures could say anything about a warranty problem when the Mobil 1 10w30 gets that low of a Cp at -25F.
 
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9,448
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Well it is hard to directly compare 5W30 to 10W30 because they use a different temp -35F as compared to -25F. Bascicly stay below 7000Cp and you are usualy fine. 10W30 has done fine for a long time and will work just fine for a lot of people. Personely I wounder why anyone would mes with either a 5W30 or 10W30 when you can a 5W40 that is almost as safe in most peoples enviroments. If you truely have a need for oils that will crank,pump and flow at artic temps then the 0W30 and 5W30 oils really shine. Some people belive that the thiner oils cool better and flow better as well at all temps. When a car company especialy for the N. American market sets their guidelines up CAFE is their main isseu. Then they also want to make it idiot proof so that even the worst oil in that weight that meets the API minium will work. They do not want BUBA to put 20W50 in his ruck in Georgia and then drive up to Canada in December and ruin the truck trying o start it at -35F. If they just put 5W30 on the cap and only mention 5W30 in the manual they have all their liability issued covered. Olree at GM claims that most bearing damage to engines is caused by cold cranking with too thick of an oil. He claims this is especialy the case in cold environments!
 
I would like to know if Mobil 1 10w30 would flow as well from say "0" to "-10" degrees F. as a Dino oil rated 5w30 ? I've read that synthetics flow better and lube better than dino's. I know that most vehicle manufactures state in their owners manual that you should use 5w30 for below "0" degrees F and you can use 10w30 above "0" degrees F. I would assume they are talking about dino oil when they make these statements. Wouldn't a good synthetic like Mobil 1 10w30 provide better protection to say -10 degrees F than a dino 5w30???
 
Thanks John good information. This confirms that I will go with Mobil 1 10w30 in both my vehicles, based on UOA for both by others with the same engine. I will do my own UOA and confirm my choice.
 
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