I've been using 0W20 oil for the past month and have improved mileage by .6 mpg. I didn't think it would make any difference but it has consistently improved my mileage for the past 1500 miles. Bottle says that it meets specs for 5W20. Just thought I'd let everyone know.

 

What brand?

 

??? brand

 

Thinner oil is easier for the oil pump to push so it's less drag on the engine.
Probably Mobil 1.

 

any negative effects of using the oil. I saw the mobile 1 0W next to the 5w when I bought mine, and was wondering about it.

 

I think Mercedes uses it in their European models. It doesn't usually get as hot over there. I'll stick with 5W20 myself. That's thin enough.

 

lots of engines use 0 weight oil now. its not smart to do if your engine manufacturer doesn't recommend it.

 

Brand is Mobil 1, though I know Amsoil makes it also. Advance Auto is having an oil change special with 5 qts of Mobil 1 and a Mobil 1 filter for $27. I agree with concerns over viscosity, I'm going to research this more. One other thing I've noticed; it take longer for the truck to get to normal operating temp with the zero weight. I'm hoping this is because of reduced friction.

 

I changed my oil acouple weeks ago with castrol GTX syntec 10w30. do you think thats too thick?

 

thicker than you need it, but nothing at all to worry about. I think the Hemis are specd for 5W30, so you at least got the 30 part right. remember the W part is the cold rating, with it getting warmer out now you will be absolutely fine. I wouldn't do that in the dead of winter, but i bet it still wouldn't have problems.