Looking at some of the pictures on the previous threads looks like they are all Diesel which I know nothing about.
The M.H. that I have is a gas driven one.
The fan in front of the engine has a fan clutch that come on only when the engine is getting hot and if I am going up a hill in the summer months the fan will increase its speed as the engine get hotter it seem to increase its speed to keep the coolant at a constant temperature.
Which I think is great.
Just a thought.