Originally Posted by
Winnie
I agree with what MB says here. In fact at highway speeds or even general road speeds, a fan is more of a hindrance than a help.
But offroad at speeds below 40kph then fan does help a fair bit then.
I have a fan on my cross country cooler wired to ignition so it is always running. I would forget to switch it on at low speeds if I had it on a switch, and I think it helps with heat soak when stopped at lights etc, it always has cooler outside air flowing through it so doesn't soak up as much heat from the engine.