From your picture, it looks like the fan clutch that you took out was not an original MB fan clutch, but rather an after-market one. Its strange that you would go through 2 fan clutches already on a 99 E300D

BTW, to answer JimmyL's question, the purpose of the fan clutch is to provide additional cooling to the radiator, especially in stop and go traffic under high ambient temperature conditions.

Phil

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]