bmw540san. Yes, the aux fan in front of the radiator is a pusher fan. It is my understanding the aux fan is triggered by radiator temp and the air conditioning read by controller.

Once I remove the clutch fan I would attach the aftermarket puller fan to the radiator, leaving the shroud in place. With the PWM controller on the puller fan the result should be that the pusher fan will not get a signal that turns it on or it will be on less. Since I don't know how much air the clutch fan pulls when it is at full lock, the aftermarket fan would need to be a high rated CFM fan.

The only reason to do this is to increase horsepower due to less drag on the engine. If it doesn't do that I have no reason to make the change. I have done this for many years and always felt it was worth the expense but I am only guessing it increases HP on and X5. Depending on the radiator coverage by the aftermarket fan I may go with the aluminum plate to be sure the fan is drawing all the air it can.

I really appreciate your input.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas