Here\'s the new visco-electric fan clutch off a Mercedes Sprinter.  We LOVE this thing!  Having suffered through an endless stream of fan clutches that either didn\'t work at all, or only worked for a little while, we were fed up with the thermostatic spring variety. Pretty sure we\'ve spent more money replacing fan clutches (usually at the side of the road) than we did on this one.  I also found on our latest trip that the auto parts stores for the most part don\'t stock any but the lightest duty fan clutches, which aren\'t sufficient for our application.
I trimmed about 1.25 inches off the ring/lip of the Curtis two-piece shroud so the shroud approximately lines up with the the rear side of the solid ring on the new fan.  It\'s a 20" fan, vs 19" for the oem fan.  I think it might possibly fit the stock shroud if you removed the "horse collar", but I haven\'t gotten to test that theory.
You do have to remove the stock studs on the front of the water pump; a couple of nuts threaded on each stud against each other made quick work of that. The fan clutch is held on with bolts with allen wrench heads for clearance (1/4" wrench, I believe).
It\'s much quieter than the stock fan, or even the later style offset blade fan we were using. It sounds much different than the stock fan too, more of a whir than a roar.
We\'re using this with the Dynamic EFI "EBL" fuel injection computer (a stock 7747 GM ECM with a special "daughter board" added on). This allows direct control of the fan via the EFI computer.  It works marvelously; just wish we could have done this sooner!!!
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