Jun 3, 2019 · I feel that FCA and Cummins would love to require 5w-40, but are afraid of people throwing a hissy fit over having to use synthetic, hence the conventional 15w-40 option.

2019 Ram 2500, 6.7 Cummins, towing a 10K fifth wheel in Texas. Cummins recommends 10w-30 above zero, REQUIRES 5W-40 below zero. I had dealer change the oil and use full synthetic. They used 5W-40. Is that ok for year around use with our hot summers? Is 10w-30 even available in full synthetic...

Feb 21, 2023 · The owners guide recommends 10w-30w in above zero temps but WHY exactly when we all know the 5W-40 can also be used in summer and looks like most of you do use 5w-40 year round. The oil cap shows the sun 10w-30 and a snowflake 5w-40 and lots of post about cold weather but what makes a 10-30 oil recommended in Summer?

Mar 2, 2023 · This is not another oil thread about what to use but info I'm sharing after getting back my oil report from Blackstone. No one has been able to answer with proof from cummins or stelantis what grade oil comes in the current 6.7 from factory, 10w30 or 5w40. Just change my factory fill oil at...

Jan 26, 2020 · Not wanting to start a war here just looking for input! Most synthetic diesel oils come in the 5W40 viscosity. There aren't as many choices for full synthetic oil in the 15W40 viscosity. Anyone have any preferences by viscosity? Thanks everyone!

Sep 14, 2020 · In my experience with my 2004.5 truck, 5W-40 synthetic is fine for winter cold weather up here in Calgary where it gets to -30C/-20F. 15W-40 synthetic makes for a grumpy cold weather start. I would not recommend 15W-40 conventional oil for cold winter use.

Sep 28, 2009 · Do you think it would be a good idea to run the 5w-40 synthetic, or will the 15w-40 be ok? If i start running the synthetic, id run it year round, since as soon as i switch to synthetic, i run it nonstop

Feb 28, 2024 · 5w-40 is better. Plus like gsbrockman said I don't really see 10w-30, maybe my last trip at the parts store, best price I can find is O'Reilly's through their website they always have a discount, minor but it usually brings it down a few bucks. You'll get oil pressure when starting due to the thinner cold weight, 5w.

Aug 5, 2021 · I run 5W-40 here in N. Idaho. The truck is quieter running the M1 ESP 5-40 than the 10-30 syn blend. Been running 5-40 for 20 years everything is still running. Never an oil related problem.

Dec 26, 2012 · I have an 04 cummins with 120000 miles ben running Amsoil 15W40 for a while some people tell me to switch to Schaeffer's 9000 Synthetic 5 W40. Is this better engine oil all together for protection, fuel mileage, cold starts,more? Or is it made more for powerstrokes? Has any one tried this oil...