Mobil 1 - 15W50 - OK for cold weather?

CJH

Messages
489
Location
Pennsylvania
Can someone explain this to me please? Mobil 1 15W50 has the same pour point (-45 deg) as Pennzoil 5W30. This would lead me to believe it is ok to use in cold weather. On the other hand, the viscosity would lead one to believe this would not be a good selection for cold weather. So is it ok to use 15W50 in cold weather, say as low as minus 15 degrees F? Please explain the reason as well as giving me an answer. I would like to understand this.
 

Patman

Staff member
Messages
21,990
Location
Oakville, Ontario
Don't go by the pour point, go by the cold cranking performance. I definitely would not run this oil in -15F weather, I wouldn't even run a 10w30 oil in this weather, I'd say to go with a 5w30/5w40 or 0w30/0w40 oil. If 15w50 Mobil 1 flowed as well as a 5w oil in the cold, then they would be classified as 5w50 oils (the exception being 15w40 Schaeffer oil which could qualify as a 10w40 with it's cold cranking performance) This is one area where people sometimes get confused. They see the specs on a 10w30 synthetic having a better pour point than a 5w30 dino, but yet that 10w30 still doesn't have as good of a cold cranking performance as any 5w oil does, and that's more important in the winter.
 

Al

Messages
19,208
Location
Elizabethtown, Pa
Looking here: Mobil 1 spec sheet I would steer clear of the 15W stuff in winter (Pa.) also. You can see it gets dicy at much below -20C or -4 F. In Pa. During the real cold nights-its just not the best-although it would work. I have used the 10W Mobil 1 and 10W Amsoil and can tell you it will be good (10W) for at least -18 F. (coldest I have seen). I also use a 25% mixture of the 15W-50 with the 10W-30 Mobil 1 in my Truck and It sprang to life at -14F this winter. [ May 06, 2003, 11:03 AM: Message edited by: rugerman1 ]
 
Messages
1,539
Location
Shippensburg, PA
Hey Al... what do you think about using dino 10W-30 year round in PA? I have been switching to 5W-30 for the winter months, but I am starting to wonder if this is worthwhile. I figured I'd ask a fellow PA resident that is familiar with the climate.
 
Messages
903
Location
CA
For marketing reasons maybe they don't want to label it 5w50. I believe this is the same for other oils like 15w40s and straight weights. It may meet a lower cold cranking spec but people are used to seeing the label say one thing and that's what they want to buy.
quote:
Originally posted by Patman: If 15w50 Mobil 1 flowed as well as a 5w oil in the cold, then they would be classified as 5w50 oils (the exception being 15w40 Schaeffer oil which could qualify as a 10w40 with it's cold cranking performance)
 
Messages
2,480
No...trust me, the M-1 15-50 is NOT a 5-50. I'm using a 5-50 right now...and there's a stark contrast. The grade is API determined. If it falls in a certain temp. range, it will be either a 5, 10, 15 or whatever. And with M-1 15-50 it qualifies as a 15 weight at -20C (where 15 weight oils are measured) even though it continues to pour to -45...(may be misleading)
 
Messages
8,756
Location
RI
I use it year round. I have customers that use it year round. Oil pressure builds a little slower(and is higher) but there is no added engine noise. IMO, it works better than 5w30 dino oil during the winter here. Because SAE uses the word MAX for cold flow, it is possible that some(quality synthetic) oils can test and pass for other weights. I would guess that real synthetics have better viscosity curves(not cliffs) than dino oils. Mobil1 maybe just calls it a 15w50 over here. Mobil1 cold cranking CP is(assuming they forgot the minus-) 5234 @ -20. Cold Cranking CP for sae: The SAE spec is <7000 at -20 for a 15w. The SAE spec is <6600 at -30 for a 5w. Anybody want to wager that the cold cranking CP for Mobil1 15w50 doesn't increase from '5234' to the 5w spec '6600' when the temp drops from -20 to -30????? The coldcrankingCP Mobildiveclean nonsynthetic 20w50 is 8200 at -15. Notice how the nonsyth already exceeds the colder specs at a higher temp.
 

Al

Messages
19,208
Location
Elizabethtown, Pa
quote:
Originally posted by novadude: Hey Al... what do you think about using dino 10W-30 year round in PA? I have been switching to 5W-30 for the winter months, but I am starting to wonder if this is worthwhile. I figured I'd ask a fellow PA resident that is familiar with the climate.
Well.. your temperature in Pittsburg are probably a few degrees colder than our here in eastern Pa. If I were running dino- I probably would run the 5W stuff or at least mix some in the 10W. I'm not claiming to have good information here.
 
Messages
2,480
Al, that's a M-1 overseas spec. sheet from 1995. However, it does illustrate the point. Yes, Mobil 1 has been brainwashing the public by pushing it's "pours at -400 or whatever" for the longest time. This is a characteristic of PAO's. In either case, a 15-50 is generally good down to -20C (-5F) (as per my owner's manual). With Mobil 1 you may be safer...I believe they say the pumping temp. is -35C...however, the oil will be molasses thick. If your engine can turn it over, it will pump and that's all that matter. I don't think this "it flows better or worse" thing matters. All the engine parts are already coated...and the oil will reach the parts soon after the car is started....I mean, someone came up with the magical -20C...I didn't pull it out of my... To finalize though, I found increased fuel consumption at these cold temps. until the oil warmed up...ie. fuel was being wasted to warm-up the oil....which was frequent during frequent short trips...this killed the fuel economy...not the 50 weight.
 
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