Will it be safe to run Mobile 15W-50 this winter?

The Shape

Founding Member
Jan 11, 2002
2,224
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East ARKANSAS Delta
I need to change my oil this weekend, and with cooler temps. right around the corner I wonder if it will be safe to run the Mobile 1 15W-50? The coldest we normally see is the mid 20's and that is rare it usualy stays in the mid 30's. I have read that the mobile one is supposed to have really good cold flow chareteristics, but I am not sure. The more I read on the subject of oil weights the worse my headache gets LOL. Just wanting some opinions .
 
Do Not run 15W50 in the winter Period. Infact with your mild engine combo running that thick oil in the summer is pretty much pointless as well. You'll get lot's of mixed opinion's on this but my opinion is you don't even need such a thick oil. 5W30, or 10W30 would be the better oil to run.

Shon
 
Yeah that is kinda what I figured. Since we are in agreement that I should knock it back down to 10W-30. I have one more question. I hear thousands of horror stories on hear about what can happen when changing from regular to synthetic oil on a high mileage car (which I did without much extra oil leakage) What about changing from a synthetic back to regular oil? Any downside to that besides having more money in my wallet when I leave the store ?
 
408stroker5.0 said:
Do Not run 15W50 in the winter Period. Infact with your mild engine combo running that thick oil in the summer is pretty much pointless as well. You'll get lot's of mixed opinion's on this but my opinion is you don't even need such a thick oil. 5W30, 10W30 or 10W40 would be the better oil to run.

Shon

I run 15w50 because according to the OEM oil guage, the 10w30 would drop damn near 0, and about 40 driving. I know the OEM guages are crap, but I guess I feel better when the oil pressure is above 0 lol.
Whenever I get an A-Pillar guage pod, then I will get a new oil guage.
 
15W50 in the summer time is alright guy's... although I feel it is a bit overkill for a reletively stock engine (Rob's Horsepower) I've alway's liked 10W40 (Red Line) in the summer and is what I currently run in my 408.
As for colder tempurature's I would not even consider running 15W50. Basically it would be like molasses(Or Worse!!!) Imagine what is happening when you fire that engine up in the cold morning..... Nothing..... Your Bearing's, ring's, upper valve train, etc. etc. will all be starving for oil (Talk About Taking The Life Out Of Your Engine) because the oil pump can't pick up that cold, thick oil until it start's to warm up from internal engine heat.
10W30 would be the better bet. Period.

Shon
 
408stroker5.0 said:
15W50 in the summer time is alright guy's... although I feel it is a bit overkill for a reletively stock engine (Rob's Horsepower) I've alway's liked 10W40 (Red Line) in the summer and is what I currently run in my 408.
As for colder tempurature's I would not even consider running 15W50. Basically it would be like molasses(Or Worse!!!) Imagine what is happening when you fire that engine up in the cold morning..... Nothing..... Your Bearing's, ring's, upper valve train, etc. etc. will all be starving for oil (Talk About Taking The Life Out Of Your Engine) because the oil pump can't pick up that cold, thick oil until it start's to warm up from internal engine heat.
10W30 would be the better bet. Period.

Shon

When I change my oil next, I will put 10w30 in it because I start my car like every week when it's stored. My next oil change will probily be the last untill spring. :nonono: :mad: :bang: :(
 
408stroker5.0 said:
15W50 in the summer time is alright guy's... although I feel it is a bit overkill for a reletively stock engine (Rob's Horsepower) I've alway's liked 10W40 (Red Line) in the summer and is what I currently run in my 408.
As for colder tempurature's I would not even consider running 15W50. Basically it would be like molasses(Or Worse!!!) Imagine what is happening when you fire that engine up in the cold morning..... Nothing..... Your Bearing's, ring's, upper valve train, etc. etc. will all be starving for oil (Talk About Taking The Life Out Of Your Engine) because the oil pump can't pick up that cold, thick oil until it start's to warm up from internal engine heat.
10W30 would be the better bet. Period.

Shon

Just so we aren't giving Mobil 1 too harsh of a review...at zero degrees that 15w-50 will flow more easily than a dino-based 10w-30. Mobil 1 lists the pour point of their 15w-50 at -45.

Would a good 10w-30 be a better choice for colder temperatures? -Yes

Will running a 5.0 with 15w-50 Mobil 1 in it through a mild Arkansas winter ruin the engine? -Certainly not, especially considering the bearing clearances in your engine.

Just out of curiousity, how cold does it get down there in the winter?
 
battyice said:
Just so we aren't giving Mobil 1 too harsh of a review...at zero degrees that 15w-50 will flow more easily than a dino-based 10w-30. Mobil 1 lists the pour point of their 15w-50 at -45.

Would a good 10w-30 be a better choice for colder temperatures? -Yes

Will running a 5.0 with 15w-50 Mobil 1 in it through a mild Arkansas winter ruin the engine? -Certainly not, especially considering the bearing clearances in your engine.

Just out of curiousity, how cold does it get down there in the winter?
well put. :nice:

i agree (TS, you know i tend to go with thicker viscosities though). i might ask people to compare cold flow numbers and pour points of a given synthetic vs a dino oil (in this case, M1 15-50 vs 10-30 dino). the synthetic oils achieve their stability much through the longer chains and synthetic properties (PAO, PAE basestock, etc) - not through higher viscosity (thicker feeling oil). the synthetic properties keep the oil stable at higher temps, not a thick base viscosity.

every motor has different tolerances in it. i would go with the thinnest oil that maintains some sort of pressure (pressure being a reflection of resistance to flow).

now that said, 10-30 would likely be my choice for the 20* mornings. i might want the synthetic properties for cold start ups though.

i would not worry about the swap back to dino either - the detergents in syn clean out the crud in your seals. dino oil will be less likely to leak and may even slow up some small leaks a smidge.

good luck Big J.
 
if you guys are set of running thick synthetic oil over winter i would recommend amzoil. ive seen many many reports and reviews on them at my last job since we were debating on whether or not to seel the product and we decided too since it got a lot better ratings and comments from govt agencies that regulate standards for oil. but yes, 15w50 is way to thick to run in a car during the winter except for some VW's that call for that oil and diesels that call for it.
 
giddyup306 said:
I personally run 5W20 in the winter which is now recommended in a lot of newer engines.

yes, it is recommended in newer engines simply because they are newer and they are built to specs that can handle that kind of oil. the only reason that oil was made was because these cars were built for it. did anyone ever notice 5w20 anywhere before 2002? i sure didnt and i worked at an oil change place
 
I think I will go ahead and try a dino 10W-30 this change and see what sort of pressure I have. I went to 15w-30 because I was only seeing around 20-25 p.s.i fully hot idle and about 40-45 p.s.i cruising with the 10w-30. That scared me and the 15w-50 brought those numbers up about 10 p.s.i across the board. But after doing a few searches here and on other boards my numbers with the 10w-30 seem to be completely safe and normal for an older engine. If my pressure dips to low I can always change back.