New Alternator, then mysterious coolant leak
 

I had to replace my alternator on my 560SL this week, and upon driving back from the shop, a puddle of coolant was on the garage floor the following morning. I watched it for one day of driving, and strangly enough, it doesn't leak for about an hour after the car is shut down. The leak is a drip off the oil pan at about 1 drip every three seconds.

Any relationship between the new alternator (worked performed by the shop) and the now new water leak one day later? Seems pretty suspicious to me. Could he have stressed the water pump too tight by re-tensioning the belts?

What will a water pump replacment run me?