Try a fan/clutch from a 80-85 M-B 300D. Get the later plastic fan, not the cast aluminum one. Junkyard, since new parts are $$$. For kicks, I tried a new Dart SB fan/clutch on my 85 300D and it fit the water pump fine, using the collar in the box, so should fit the other way. My Mopar fan blades were too thick to clear the M-B engine parts. I was fooling with this because initially I saw >$100 prices for a new M-B clutch, then found a $30 one on ebay that worked fine. You can't swap the fan alone between Euro cars and U.S. because their clutches are smaller. The lighter Euro fans probably put less load on the water pump bearing.
