I've been able to fix a few problems (broken hood latch, etc) with my 1992 190E by searching the forum here, but I've got a coolant leak I can't seem to diagnose and a search has brought me nothing.

I found this thread from a couple years ago, and it sounds similar to my problem, but no one responded to it.

I'm having to refill my coolant every week or so and we've already ruled out the water pump (the leak is definitely coming from back near the tranny), and I thought it might be the heater core, but there's nothing leaking inside the cabin.

Any ideas guys?