Pulley Wobble?

[BMWerke]

So heres the situation, i did a tranny swap and the head gasket on my '90 325is and everything sounded good as we let the engine run for about 15 mins as we bled the collant system, in fact the car sounded new. So i took it for its first drive as a 5 speed and it still sounded good. the next day i was driving it and after about 15 mins i started to hear this knocking, come to find out the pulley for the water pump is wobbling, bad. all 4 bolts were tight before we put the fan on, any idea on what it could be??? and the belt is not too tight. thanks

[OrganicMechanic]

if the bolts are tight--and it is wobbling, it could be that the bearing in the waterpump has failed. Pull the belt and confirm.

[call me jack]

my car did this too for awhile. but i had 2 things going on. my is actually warped, while my my water pump was simply defective. i just replaced the water pump, the other day, and the car is pretty much parked for the winter.

[recall]

I had the same thing happen after changing the timing belt and it turned out to simply be that the pulley worked itself loose. We torqued it down to spec with a torque wrench, but apparently that either wasn't enough or it was hard to get a good reading on because the pulley moves... after checking for play in the pump and seeing no issues I put the pulley back on and got it as tight as possible (make sure the washers are there).

I don't think I'll use a torque wrench on any pulley again...lesson learned.

[BMWerke]

i well check it today, after i eat :) . i was gonna get a new water pump anyway.

[Tbolt]

lock-tight them