Rotella Synthetic

#25ashley · 10-30-2009, 05:27 AM

Went to change oil (from the previous owner) Wanting to run Rotella Synthetic. Truck calls for 15-40 conventional oil. Only thing I could find,was Rotella 5-40 synthetic. My question is, Is that exceptable? Do they make a 15-40 synthetic? Live in the mid atlantic region,where it does not get too cold nor too hot. I'm thinking the 5-40 would be ok. What is the opinion here?. Thanks for the help

**ob_1jr** · 10-30-2009, 05:50 AM

5w40 will be fine. the 5 is just for colder weather. I havent seen any sythetic that wasnt 5w40. That is all i have run in mine....-50F to 90F in the interior of alaska.

Dura2thaMax · 10-30-2009, 07:26 AM

I have been debating on that too as I live in South Dakota. I can get well below zero here and over 100 in the summer.

#25ashley · 10-30-2009, 07:31 AM

So even in the dead of summer when it get's to be in the high 90's and pulling a 30' camper. I should be fine?

**ob_1jr** · 10-30-2009, 07:37 AM

yes you will be fine. the 40 weight is for the hot.

**GMC4Me** · 10-31-2009, 12:14 AM

Quote:

Originally Posted by #25ashley

Went to change oil (from the previous owner) Wanting to run Rotella Synthetic. Truck calls for 15-40 conventional oil. Only thing I could find,was Rotella 5-40 synthetic. My question is, Is that exceptable? Do they make a 15-40 synthetic? Live in the mid atlantic region,where it does not get too cold nor too hot. I'm thinking the 5-40 would be ok. What is the opinion here?. Thanks for the help

AMSOIL makes a 15w40 full synthetic diesel oil, which I use. You might want to think about staying with 15w40.

Your owner’s manual says 15w40 because your oil pump is designed to work optimally (pressure and volume) with this viscosity of oil within a specific temperature range. Will running 5w40 hurt anything? Probably not, but GM did not pull this requirement out of their ear for no reason.

IMO, unless you are in serious cold country I would stick with a 15w40 for all seasons.

**ob_1jr** · 10-31-2009, 01:19 AM

Depending on where you live and the temps you see will depend on the weight of oil that you need to run. the only difference between 5w40 and 15w40 is you can use the 5w40 in colder weather. They are both rated for the same hot weather.

kman2468 · 10-31-2009, 01:31 AM

Quote:

Originally Posted by ob_1jr

5w40 will be fine. the 5 is just for colder weather. I havent seen any sythetic that wasnt 5w40. That is all i have run in mine....-50F to 90F in the interior of alaska.

sorry but i have to ask this... it reaches 90 in alaska??

**ob_1jr** · 10-31-2009, 01:34 AM

Yes it does in fairbanks...the interior.

kman2468 · 10-31-2009, 01:36 AM

Quote:

Originally Posted by ob_1jr

Yes it does in fairbanks...the interior.

well i learn something new everyday haha
i thought it was mostly always cold there