Thanks for the warnings... I agree that a new pump is best, but the price I've been quoted so far is over $300! I think that's obscene for any water pump, regardless of who made it. And I don't like the idea of a rebuilt pump. My 1992 190E 2.3 developed a leaky radiator (cheesey plastic end tanks) at 70K miles and then the water pump started leaking (bad seal only) at 75K miles. All I could get from the dealer was a rebuilt pump. The replacement looked like it was "rode hard and put up wet". Not a very professional rebuild job, it's not leaking yet... but only has 8K miles since replaced. It does make me wonder about MB quality when the original pump doesn't even last 36K miles. Looking at the pulley arrangement however it's clear that this is a very poor design. It's also possible that the dealer had the belt tension too tight. The car had some work done when new to fix an oil leak at the front cam cover. According to the dealer, the two dowel pins which hold the cover in place were missing from the factory. It still leaks a bit, so they didn't quite fix it either, but they had the belt off during the repair and may have tightened the tensioner too much during reassembly. In any case... I'll fun for the better part of a day replacing the pump and cleaning up the warranty service mess. Thanks again for the quick replies.