In Reply to: bad idea , dissimilar metals react! posted by Angus on August 16, 2001 at 20:55:31:
these fans and this mounting technique work fine on a normal copper core radiator in a normal car but the bmw one is aluminum and the two metal's dont get along ,where the copper pins and aluminum touch (and get wet from rain)the corrosion will be accelerated and you will soon be replacing this radiator!!!!!!! not only that the vibration of these motors will soon have that fan loose and the copper pins will rub right thru the aluminum cores!!!! i would suggest you build a real mounting frame for the fan that mounts to body at side of radiator before you cook your motor.
Here is what I got done last night. The fan is really nice, compact, and is rated at 1200 CFM. I bought a 40A relay and a pre-wired relay plug with it. I went to BMW of Bellevue last night and picked up a 91 deg C switch to put into one of the plug holes in the botom of the radiator. The fan did not come w/ a good way to mount it, so I ran to Action Auto parts and got a kit from there. Basically, it is 8 copper pins that you carefullt slide thru the cooling fins and secure on the other side with rubber locking pads. I'll see how it works, but the test fit in the car was great.
Here is a head on view of the fan mounted on the radiator:
3/4 Profile View:
View of the mounting pads on the front of the radiator. They just friction fit slide onto the copper pins, not physically attached to the radiator itself:
Here is another shot after I painted the center part of the fan black:
Part 2 will be the actual wiring, including the temp switch and a button on the dash for manual activation.