Oil Weight

[kcw12]

What does everyone run in there truck. I normally run 15w-30 but i was thinkin about switching to straight 30 weight. Any input is appericated

 

[sle2115]

Most I know, myself included, run 15W40 of one flavor or another. Don't ask what brand as that will start a small skirmish, something similar to Iwo Jima...

 

[kcw12]

i ment 15w-40. would there be anything wrong with runnin 30 weight?

 

[tonkadoctor]

i ment 15w-40. would there be anything wrong with runnin 30 weight?

Nope, not if it's diesel rated but it will probably start a little harder when cold and probably very hard in the winter. Curious why you want to do that.

I run 15w-40 Rotella T in the IDI and 5w-40 Rotella T synthetic in the PSD.

 

[86 1 tonhauler]

the ford maunual suggest 30w oil for all types of weather thats what my manual says for these engines

 

[BROWNIEBOY525]

i run 30w in the summer then switch to 15w40 in the winter. but that fits my oil change interval perfetly so that why i do it.

 

[kcw12]

Finally found the manual, it has 30 weight in there. Dirt da derrr im a bright one tonight. All good though

 

[Mr_Roboto]

I tried straight 30w, it seems to give lower oil pressure at hot idle and I'm going back to 15w40.

 

[Diesel JD]

Yup...I found what you did Roboto, but the oil samples didn't indicate that it caused any problems I didn't already have. It was a very slight difference like 9-10psi with the 30wt and 12-14 psi with the 15/40. The 15w40 acts like a 15wt cold and a 40wt hot.