Hydraulic fan

[caymann]

Trying to clear up my understanding of hydraulic fans on the radiator.

1. It is supposed to run at all times at low speed
2. Based on a solenoid (temperature) it will speed up or slow down
3. It doesn't steal power from engine

Are these correct?

thanks
jim

[BigSkyBob]

The fan for my side mounted radiator comes on at 210 degrees and shuts off at 195 when I'm ascending a grade. So it's temperature activated. It does not run at low speed under any conditions. When the fan is running it obviously takes power to run it and that is supplied by the engine driven hydraulic pump, so it does "steal" power from the engine.

[Pusherpilot]

On our 04 Imperial ISL 400, side radiator, The fan comes on in a variable speed fashion depending on the coolant temp. There is a valve that uses wax to determine how much hydraulic fluid to let thru to the hydraulic fan motor. Being continuously variable the cooling is extremely even rarely fluctuating more that 5 degrees no matter what grade we're on or the outside temp. This insures that only enough power is "stolen" from the engine to keep it cool.
The only thing I don't like about the side radiator is the tendency to raise a huge cloud of dust when the engine is hot and we are driving on a dirt road, usually the interior roads of CGs!! Very annoying to the neighbors, wish I could turn it off for the few minutes it takes to get to the campsite etc.
Ron