I don't think there's much to worry about. I drove for quite a while with one fan out. Just watch temps when stopped, etc. If temp gets too high you can always dump some heat by turning on the heat to max.

The fan motors get gunked up with bugs and debris, although you wouldn't think they would, the way they are facing. I think all our cars of this vintage are starting to experience failing fans.

I replaced the failed one on my car and I've tried to clean out the failed one. I've reassembled but not tested it yet. You have to bend the motor can tabs to take out the guts, which is a PITA, and it's ugly when reassembled.

Rgds,
Chris W.
'95 E300D, 240K