On my 300E it was a year later and another 5000 km (3000 miles) I replaced the water pump (replaced at 205,000 km which is just over 120,000 miles). I watched it carefully but the leak became progressively worse and temperatures were running too erratically, too high, and too often.

The new pump works very well, temperatures are very stable and right on spec. Also replaced the belt tensioner so hopefully I'm good for a few years.

By the way, the Snap-On tool FLX-M13 to get at the virtually hidden bolts works very well. You have to put a lot of torque on it but it will turn the bolt. I bought mine on Ebay for $25 which was half the local retail price.

hope everything goes well,
Paul

Dont' forget to first ensure that it's not the hose taht is leaking. Also check the clamps first to see that it 's good. A while back I thought my pump was gone. While I was in the process of pulling out the pump, I found it was a failed clamp (it snapped) which allowed coolant to leak. Replace the clamp and it be fine since then.