The well-made Kenlowe electric fans are popular accessories on many a Landrover. In fact you can replace the genuine mechanical or viscous fan easily with one or 2 electric fans. Works especially well on TDI's as these engines run very cool by themselves.
In winter you get better and faster heating.
Kenlowe advertises 8.5 % energy savings which seems a bit high to us but there's no doubt they make for a small economy as well as free a couple of horses. A large fan takes 3-5 bhp's if you need it or not. The Kenlowes are switched by thermal contacts so they go on only when you need them. Friends of us say the fans cut in very seldom, in winter not at all and in summer only in slow going trafic. They take between 13 and 26 amps of draw. Come in complete kits with everything you need except standard tools - no drilling or cutting.
Offroad TDI's stay very cool too. I have not yet made own experiences with my V-8 and Kenlowes so I can't yet tell if the bigger heat output of fuel engines in hard conditions is successfully mastered.