hey can do and Bill

thanks for the helpful info...I just went out and bought a used aux fan from the junk yard. I installed it and it runs like my dads 300E aux fan...kinda loud but with a little clicking annoying sound. The fan seems to be a little off balance because when i put my hand on the black plate when its runing, i can feel it vibrate rough. Do you think i should keep the fan? I bought it for 69 bucks but i have a 30 day return policy.
At what temp should the aux fan turn on? My aux fan turns on at redline 250 fahrenheit (121.1 C)....I'm not too sure if this is normal. Also my radiator fan does have a clutch in it and it has 6 blades (aluminum). I'm assuming my fan clutch is bad, since it doesnt move freely when the engine is turned off (only turns about a quarter rotation). Should i replace it...its pretty expensive, costs around 100 bucks. Last, are the updated 9 bladed radiator fans in the later 81-85 300SD models? I found one off the net for cheap 30 bucks, just wanted to know if its the same fan your talking about can-do.

thanks
Allan