5w30 is not to thick I would do all 7 quarts of 5w30.
here is a chart that shows how they work . As you csn see 5w30 works to -30*
View attachment 120421
There are also these charts, though idk about the accuracy of all of them since they don't all have all of the grades listed.
However, viscosity for temperature is not all you should look at. HTHS, or high temperature, high sheer resistance in addition to base oil and a good additive pack are very important from what I'm picking up.
As far as Redline goes, which is what I just got delivered and am about to put in, the 5w40 and 0w40 have very high HTHS on their website. And, given the first chart below, those two give the widest range of operating temperature. With a mix of the two being the best middle ground.
However, to simplify, the first number "xW" is how good it does in cold. 10w can go to freezing or 10 below, I believe. 5w can go 20 below, and 0w cam go 30 below or farther. I'm not 100% certain in these numbers or information, but yeah.
The second number (20, 30, 40, etc) is your viscosity once it's heated up. Hemi's are rated for 20wt mainly to meet carb fuel economy standards. 30wt (and is reportedly even what's recommended in the 3rd gen RAM 2500 manual) is just fine to run, and many also run 40wt no problem as the 6.4 recommends 0w40 PUP.
I'm currently about to put 5w30 in mine and I live in Florida. Between now and the next oil change, I want to find out more about viscosity mixing and running 40wt in the 3rd gen ram era 5.7 before I pull the trigger in my theoretical ideal oil of Redline 5w40 and 0w40 mix.
Another important thing is the filter. I'll keep it simple. Royal Purple or Fram ULTRA. It has to be the Fram ULTRA if you go Fram. The orange frams are said to be terrible.
((the fram is cheaper than the royal purple filter. By about $6 usd on Amazon.))
Also, get a bigger filter than stock. Just use Amazon to find the one recommended for your ride, then go to Summit and type in the filter name and find all the ones that have the same size threads and gasket as your recommended one and use the biggest one you think will fit.
In my case, my truck would take a royal purple 20-253, and I ordered he larger rp 30-8a. Which was actually the only other one with the same threads and gasket as the recommended one, and it's twice as long. {I looked under there. It should fit just fine. But mine's a 2wd 05, so a 4x4 or newer generation truck might be different.}
Either way, good luck, dude. This post was much longer than I anticipated.



Sent from my magic 5-inch