BNielsen
I'm Awesome
My truck doesn't have any issues with heat when towing, and the fans are set to turn off above 35mph. Were the truck to get hot and need a fan while moving, engine driven is superior. I will not remove the engine driven fan from my dually, but I haul big and heavy with it. What radiator are you looking at for an upgrade? Stock 3500 or aftermarket?
Depending on what you're working on, the size isn't always an issue. The air doesn't cool the engine though, that's what the coolant is for. The dually will throw some serious heat though after a mundane drive. I'm amazed the stock cooling system works so well on it.
Aftermarket 3" thick rad, and probably running a good coolant like Shell/Rotella and maybe Water Wetter, similar set up to what someone is running on his truck. (That someone is in a groupchat with me, Biggershaft96, Gavin, and a couple others)
I can't seem to find a straight answer on which is better, I do plan on towing with my truck, but I'll probably only ever gross 13K max combined and that'll probably be a rarity.
I know after my quick 6 minute drive home my engine bay is like the surface of the sun.