last week i changed the water pump in my r33gts-t s2 as it had a small leek at the top ,i used a second hand pump that was almost new- after putting it all back together and using a new genuine timming belt there was a dull whinning sound coming from it as it was warming up i was giving it slight revs to try and pin point the sound then the hole front off the pump ripped itself to peices and dropped the fan into the radiator wich caused enough damage to have to buy a new radiator. i thought it might have been the second hand pump so i got a brand new one and radiator and spent most of the week re installing it & finished it today and it was all sweet so drove it 50km to work with no probs but at midnight when i went to leave i gave it a rev in nutral to aroumd 3500rpm then it all shat itself like the week before --now my cars left at work 50+km from home with the water pump shatered again -so i need help what could i be doing so wrong --could i be overtightening the alternator/waterpump belt that might cause it to rotate of ballance then brake with a sudden rev or something else ?
this is the first pump it still spins so it hasnt seezed up the second new pump has brocken in the same way