The fan is working correctly. It just does not do it well enough. The stock rad is used with out the shroud and I was told the current set-up would work. The fan attaches with zip tye like things slid through the fins of the rad with a plastic nut type thing on the front of the rad. the fan rest against the rad. There is not much room for a fan and shroud. I've been told that the4bt does not produce much heat, In fact I might need a grill cover in the winter.
Ige, Do you have manuals for the 4bt available through your work? are there fans that bolt to the pully on the 4bt? I could build a custom shroud with that tpye of fan if there is room.