Johnny,
The oil cooler might be in the lifter valley if it is the oil/coolant cooler that is used in the cars.
demarpaint,
Interesting, cannot find any comment like that in my manual. I was thinking it was more a towing thing like the truck, which makes sense to me.
KC & demarpaint,
No need to be on or off the bandwagon really. This allowance by Chrysler is a good thing. Don't forget about the temperature factor in viscosity. In a lot of apps and a lot of usage patterns 5w20 is very likely sufficient and will see an engine to a long healthy life. To me Chrysler here is saying, if vehicle weight is 14000#+ it is not one of those times. It makes complete sense to me that this would heat the oil to higher temps than running around empty. Looking at Petro-Canada 5w20 vs 5w30, the 30 gets you approximately another 15 degrees Celsius. So let's say when the 5w20 is 120C it is the same viscosity as the 5w30 at 135C for example. I don't see this as 5w20 not being good enough, just not thick enough at this temp in this vehicle. Personally, I haven't seen over 95C in the Charger on 5w20 and I can guarantee that it will never have a GVWR or 14000+!