# Mobil 1 0W-40 or Castrol Syntec 0W-30 for Northeast Winter?



## pipo (Oct 15, 1999)

I ran some viscosity graphs and it's very clear, based on the kinematic viscosities, that Mobil 0W-40 has much lower viscosity for cold weather starts. I was surprised to see these results, because the 40/100 degree C viscosities of the GC 0W-30 are both lower than the M1: M1 75/13.5 GC 72/12.21 Shows you what M1's high viscosity index does!

Here is some of the data I obtained:

At 43.11 degrees F, the viscosities of the two oils are almost equal: M1 180.8 GC 181.8

At 32 degrees F, the M1 already has substantially lower viscosity: M1 563.3 GC 608.3

At 20.89 degrees F: M1 2520 GC 3047

At 9.78 degrees F: M1 19038 GC 27557

And at -1.33 degrees F: M1 313764 GC 607601!

Mobil 1 0W-40 wins!:what:


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## Super Hans (May 27, 2011)

Now try it with 5w-30, Edge or Ultra or whatever.

Be careful with some of the published data. It merely reflects the min and max values allowed per spec, rather than actual. Castrol does this a lot.


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## finklejag (Apr 4, 2002)

I see you are still on your Edge 5W-30 kick!  I guess the Bitog crowd didn't buy it, and now you will try it over here.


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## gmikel (Nov 10, 2010)

*be carefull of soup*

banned under multiple user names both here and bitog


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## pipo (Oct 15, 1999)

Interesting. Castrol Edge 5W-30 has lower viscosity at all temperatures down to -5C (23F), then M1 0W-40 turns the tables at -10C (14F).


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## pipo (Oct 15, 1999)

I realized that I had the C to F conversions wrong in the original post. The temperatures are corrected below, showing an even greater cold weather starting viscosity advantage to M1 0W-40 compared to GC beginning at 68F.

At 68 degrees F, the viscosities of the two oils are almost equal: M1 180.8 GC 181.8

At 32 degrees F, the M1 already has substantially lower viscosity: M1 563.3 GC 608.3

At 23 degrees F: M1 787.9 GC 871

At -4 degrees F: M1 2520 GC 3047


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## Super Hans (May 27, 2011)

....but those numbers aren't too far apart. 


Edge seems to be a solid performer, or am I missing something?


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## pipo (Oct 15, 1999)

Super Hans said:


> ....but those numbers aren't too far apart.
> 
> 
> Edge seems to be a solid performer, or am I missing something?


The Edge does look good in this UOA, and is probably better than the GC for cold weather starts. Where I live in the so-called mountains of western MA (if you call 3000 feet a mountain), we do see subzero F temps on a regular basis, so I think I'm going to stick with the M1 0W-40 for the winter and do a UOA at about 5000 to see what's happening.

Thanks for all the info you provide. Has helped me along in my learning process.


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## gmikel (Nov 10, 2010)

*somebody elses uoa is just that*

it's not your car, it's not your drive style or cycle, it's not you driving. to many variables for my taste.


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