Mine is an '83 and doesn't have a fan clutch either...

On the thermostat replacement just make sure the new one goes in the same way as the old one. I replaced the one in my 240D once and put it in backwards. You get very weird results, mostly overheating. I was very embarrassed to have my Indy write "removed, reversed, reinstalled" on the receipt...

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Sadly Benz-less