[krazy]

The basic explanation for a pull configuration being more effective than a push configuration is that when a fan is pushing, more air flows through certain parts of the radiator (mostly in a doughnut-shaped ring corresponding to the blade area of the fan). When the fan is pulling, it does a better job of creating an even partial vacuum, which pulls air through all areas of the heatercore much more evenly. The mroe surface area of the heatercore you take advantage of, the more heat you can transfer.