I have a friend who is considering replacing his older 5.2L Ram 1500 pickup with a megacab 2500 with at 5.7 hemi V8.

He tows a lot, but he can't justify a diesel as he only drives around 10k miles a year.

I know my wife's Charger R/T with the 5.7 multidisplacement system requires 5W20 oil (I use Mobile 1).

I'm assuming the pickup truck version of the Hemi would use the same (since the MDS depends on the oil viscosity to work).

My thought is 5W20 seems a bit thin for hot summer towing.

Do the trucks have massive oil coolers? I'd worry about the long term effects of thin oil when running for extended periods of time at near max. engine capacity.

Any opinions?