[Lawrence Coppari]

Like you said, it does put a bigger load on the bearings. Whether that was the cause of the pump going out is not clear. If the water pump shaft wiggles, then the bearing are gone. That will ruin the seal. If the shaft does not wiggle, then it was just time for the seal to go south. I imagine the least robust bearings are the tensioner bearing that is closest to the water pump and the water pump bearing. But when you look at the way the system turns, the pump and tensioner bearings are on the slack side of the belt. The biggest load is between the crankshaft and cam tower. It is a straight shot from one to the other. Any streaching there allows for less tension on the side that turns the water pump.

By overtensioning the belt, the belt itself could be harmed. If I were you and they admit their error, I would ask for a new belt. Maybe you could get a new belt tensioner out of them as well.

The tensioner can be mounted backwards. One side has a lip. There also is a specified direction you turn the tensioner to tighten the belt. It is the opposite direction that the tensioner for the balance shafts is turned to tighten that belt.

Sounds like they really overtightened it.