Water pump failure after harmonic balancer replacement??

[JAY4]

I just had my Harmonic balancer replaced on my 112 (car is a '98 C280). When I picked the car up I drove a short distance to the gas station. I got out of the car and it was running I could hear what sounded like the belt squeeling. I immediately took the car back to the dealership and of course the service dept. had just closed for the day. I brought the problem to the General Managers attention, he said no prob. we'll take care of it tommorow. So I called the following day to schedule an appointment. (The balancer was replaced on Monday-meanwhile the squeeling is getting more apparent) They said the soonest they could get me in was Fri. morning. I took the car in today,my service advisor told me that the tech. probably forgot to adjust the belt tension. A few houres after I dropped it off my servive advisor called me and said (guess what) "the squeeling is coming from your water pump, we can replace it for you today for $640.00". This problem did not exist before the harmonic balancer was replaced, and the car has never run hot. What do you all think, could improper belt tension take out my water pump? Or is this just one of those "things"? The balancer was replaced before it failed. I just wanted to add.......I'm not trying to rip anyones head off. I have warranty (an extended aftermarket one) on the car and they are covering everything except $93.00 outta' pocket. The dealership has my car now and they gave me an '05(or '06?) C240 for the weekend. It could be way worse, I guess. I am just curious how this might have happened.

[jnenad16]

overtightened belt will cause pump bearing failure, but right after the repair, I dont know. the belt would have to be super tight for the pump to fail right away.

nenad

[benzfan]

The belt tension is automatic, and can't be 'overtightened'. It's that way on the inline 6. HOWEVER, there are 2 different diameter pulleys used on the inline 6 (I honestly don't know about the V-6). 80 and 92mm. Each requires a different belt. If someone doesn't get the right belt, and forces a shorter belt onto a larger pulley, you can get all sorts of device bearings and/or bushings failing. I don't know if something like this has happened in your case, or if in fact the shorter belt can be forced on, but it might be worth investigating.

[SLAMMED_C]

sounds like just "one of those things".. the belt tensioner on the v6's is self adjusting.. so that rules overtightened belt out of the question..
It could be just one of those things that the waterpump was on its way to fail and was disturbed as the balancer was replaced.. and then caused it to fail?.. very possible.