I would say no, it has been proven that the lly's cooling system is not capable of doing its job whet the trucks are worked hard. and i dont think an electric fan will move enough air to help. Lots of guys have been working on overheating fixes forthese trucks and the only thing that has worked so far is the addition of another small radiator after the stocker!!! an electric fan might free up a few hp but i dont think the other effects it could cause would be worth it!!
Flexalight claims a 2 mpg inclrase and 27hp freed up by going to their dual electric fans. They flow like 6200 cfm. I think it would be a good idea. I am looking into customizing an kit for my dodge.
I would say that if the cooling system is not capable then electric fans couldn't hurt. If anything, it would help reomve a large load against the motor, thus reducing the amount of heat it builds.
I think we are going to install a set on a customers 05 next month. If we do, i'll do a write up on it. He is currently having the issue of it getting hot, and the fan clutch engaing at 70mph and just draggin the motor down.
I tried converting a clutch fan to a dual electric setup on a 4L Cherokee once.
, used flex Fans, Highest cfm made for their size, did everything as per instructions, and it absolutely sucked compared to clutch fan, I will never do this again. And it does take a heavy amp load. Any performance or mileage benefit would be negated by the higher amp load on the alternator.
From what I've heard if you tow more than 10,000 lbs or more don't even bother. As well the Ally runs hotter. These fans have had electrical issues with thwm as well, to the point of guys just about loosing their trucks. Not worth it to save a little money on mpg or noise.