Minimum Ambient Temperature vs. Viscosity?

[williar]

You're right, Winston. While you can use straignt 30w for 40° F. starts, that doesn't mean you should; A multiweight oil would be better.

And it's the same on the other end. While you can run a 20w oil above 100° F, that isn't wise either, in most engines.

Which is why we have multiweights.

 

[road_rascal]

quote:

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Originally posted by Winston:
If I lived in Minnesota, I would run 0W20 or 5W20 oil in the winter if my manual called for 5W30. The newer 5W20 oils do not shear.

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I run Mobil 1 5w30 in both of my Fords and haven't had any problems. Granted, when it gets really cold out I plug in the car/van at work. There have been times were I had to work off site and the morning temps were -30F and the car started like it was 75F out.

 

[1 FMF]

I can tell you from 1st hand experience that mobil delvac1300super 15w40 and supertech 15w40 is good to +5F. The 7.3L diesel I had would crank over no problem and run in the morning without using the block heater.

 

[TallPaul]

quote:

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Originally posted by Doug Hillary:
Typically in heavy diesels this viscosity HDEO is specified by the engine maker down to -20C (-4F)

Typically in cars, this viscosity is usually specified down to -15C

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I wonder is there anything about a HD diesel engine (beefier oil pump shaft maybe) that makes them able to crank an oil at lower temperature than a LD diesel or even a LD diesel at a lower temp than a gasoline engine?

 

[Ugly3]

MN Driver - I don't know where you live in MN but I can tell you I can't find any weather records anywhere near as cold as you indicate. For example, the record coldest day ever in MN was -60F in 1996. Duluth and International Falls see few -40F days in a year (there were -0- in 2005, 2004, and 2003).

 

[oilyriser]

quote:

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Originally posted by MN Driver:
warm enough to change it out again. It seems that Mobil 1 0w30 and 5w30 have the same general viscosity graph according to everyone here so I will probably stick with the 5w30. If I can find

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The graphs look similar, but the 0w will be much thinner below -20 C than the 5w at the same temp.

 

[Big O Dave]

I know that this thread has been quiet for awhile, but with the advent of motor oils being commonly made from at least Group II base stocks, these low temp/viscosity specs have changed. Take a look at Chevron's viscosity guidelines.

Just a pre-holiday season FYI!

 

[jorton]

Thanks for the Chevron FAQ's.

I wonder how many folks observe the note for the 10w-40? Now I'm not so worried about 15w40 being too thick for this area. If it were SM I would use it.