Lexus4321

0w40. That's interesting. Why? The engine has tolerances rather loose, so why the need for 0w? -30F where you at? And then why 40, are you 125F+ ambient?

I do need to do dig up the article, but multi's use log chain polymers that expand & contract giving the oil the chameleon effect, but they also prohibit heat transfer. Remember that #2 purpose of motor oil is to remove heat. A straight SAE oil will cool better than a multi "w" oil. So, where i'm at, in summer, I can use a SAE30 and that will actually perfrom better (same lube, better heat transfer) than 10w30. So, a 0w40 has a ton of multi polymers in it, 10w30 much less, so although 0w40 can stretch that temp range I would be wary about using a multi of the 40 is really needed due to ambient temps, i'd run a SAE40 to get back some cooling performance.

dblshock

when your 14mi. into the trail now you find yourself stuck in mud on a 90 degree day you'll work that 4.7 before you get out in the mud to winch it out...that's the 40....and for the 0, cold morning starts at any temp (I can see -35F here) M1 or Edge really have 0/40 oils down, they test out (UOA) at the top of their respective offerings...can't miss bought on sale and after rebate.

Lexus4321

I was asking why you using 0w40 multi grade. When it's -35F outside a 0w20 should be good, and when you are stuck in mud when it's 95+F outside then a SAE40 should suffice as it provides for better engine cooling than any wide multi.

Using a 0w40 is interesting to me, just not my choice unless the daily temp swing was -35 to +100F, When it's -35 outside what's the high temp that day, -20?