0w40 or 5w40

[srjd]

I am currently running 5w40 mobil delvac full synthetic for winter where the temps can dip down to -40. I can get the same oil in 0w40 from a buddy for a fraction of the cost. My question is do I just keep running 5w40 in the winter like I always have or do I save some coin and go with 0w40. Not looking to start a huge debate on oils just looking for a simple answer. Thanks

[dereku]

Is the 0-40 diesel rated synthetic?

[srjd]

Ya they are both full syn

[dieselfreek26]

I wouldn't, I have heard a lot of the 0W-20 cars have had some issues due to the zero weight oil, dont know about the Zero weight diesel oil...

[6liter_BigSkyStroker]

We are running 0-40W full diesel engine synthetic in our CAT C9 engines in our Service Trucks and they are running alot better. This is the Second year doing it. They start alot better and run alot smoother althought it is not extremely cold yet. I am changing over to 0-40W in my 6.0 diesel because we get it cheap. It is reccommended for very cold temps. The scale goes past -40 degrees. I don't see a problem with it, especially in HEUI Systems.

[srjd]

Ya we run it in all our excavators at work all year round surprisingly enough and have had great results since we switched over. I think I'll switch over to it on my next oil change. It will be a lot colder out by then too.

[gunman41mag]

I only use regular 15-40 year round, but then again it never drops below 32*