Oil visocity for 360 Magnum

[pjc360]

I have a crate 360 Magnum in my 91 Dodge power ram 150, This engine was bought brand new by my father in 2003, it has around 20 thousand miles on it right now. He broke it inn using conventional Valvoline 10w-30 and after break inn he switched to Valvoline Synpower 10w-30 synthetic. I got the engine in 2011 and I just continued running the synpower 10w-30.
I live in Idaho where in the summer it the highest we see around 100 to 105 on really hot days, winter is the longest season here and in the winter the temps routinely get below zero, sometimes as much as 30 below. So this got me thinking maybe I would be better off running synpower 5w-30, what do you guys think? Or I could run 10w-30 in summer fall and spring and run 5w-30 in the winter? Or would I be fine just running 5w-30 all year round?

 

[Chris142]

id consider a 0w30 on those cold nights.

 

[901Memphis]

A 5w30 synthetic would be more than enough for that engine. A 5w30 synthetic I superior to a 10w30 in just about everything that counts.

You could also consider a high VI, light 40 like Mobil 1 0W40 European Formula which also has extra additives for longer runs. If you used a synthetic 5w30/0w30/0w40 you could leave it in all year and go by mileage note time.

The engine was originally specd for a 10w30 conventional wasn't it?

 

[HTSS_TR]

I agree with 901Memphis about M1 0W40 all year.

This is similar to your engine: Honda recommends conventional 10W30 in S2000 for all year and all climate the first few years, then around 2004 they changed to conventional 10W30 for warmer climate and 5W40 for colder one. Some S2000 owners in So Cal use M1 0W40 all year for daily drives and for track time too.

 

[Kuato]

Originally Posted By: Chris142
id consider a 0w30 on those cold nights.


My thought also. Amsoil's is very good, and M1 0w30 also.

But if your engine is specified by Dodge for a 40 weight, M1 0w40 would be a great choice.

 

[Flareside302]

the 5.2s were originally spec's for 10w30.

 

[Oldmoparguy1]

Thats a 5.8L. Good engine, last forever, just like all the other mopar iron engines. Don't over think this. Run 5W-30 year around, it'll be fine.

Wayne

 

[Flareside302]

its actually a 5.9.. and I forgot to mention they're also spec'd originally for 10w30. so anything near that will be fine..

 

[pjc360]

I'm thinking about running the synpower 5w-30. I've always ran Valvoline oil because that's what was in our shop as a youngster growing up. The engine was speced for 10w-30 conventional according to what I've read online.
And I'd rather run an oil that I can run all year round. Synpower 5w-30 is good for -20 to 100 correct?

 

[901Memphis]

Yes a 5w30 synthetic is good for - 20F climate.