[Rorty]

Originally Posted by rxpo\";p=\&quot

A few things I learned about cooling:

Fans that are used to push air are only good for cooling circuits that have no direct obstructions directly in front of them. *Otherwise you create eddy currents in the air flow, lowering the CFM and reducing effective thermal transfer.

With obstructions (i.e. radiators or the other term: "air-to-water heat exchangers") or sharp bends in duct work, you want the fan to pull air. *Air being pulled can easily come from any direction.

The fan blades should also sit properly in the venturi, or you reduce the air flow.
A fan blower working well will run with a noticable drag. *Obstructions or poor positioning will make the fan spin faster than normal becuase the blades are not cutting and moving the air effectively.

What he said.