aux bel shreading

i have a 300 tdi disco i had to change the belt tensioner as it was failing and shreading the belt replaced the tensioner and belt and it done the same
any thoughts

Whats is the nature of the failure of the tensioner? It sounds like the problem could be elsewhere. Might be worth turning all pulleys by hand, inspect them closely and check that theres no damage such as sharp edges. Also worth checking that nothing else has come adrift in the engine bay and could be interfering with the belt.

it was the rubber breaking down inside the tensioner making it not to run true i will have to check to see if there is any play in the pas pump pully etc the belt was ok when the car was ticking over i seem to think its when the engine is under load that it starts ripping the belt to bits

Check the power steering pully for forward and back play as the key can wear on the pully allowing it to float in and out which shreads the belt but the pump can still operate.

also worth checking the crank pulley. there was a thread on here somewhere about it. I has a rubber centre, for damping, and when worn can cause the pulley to run out of line, and shred belts

I would look for damage to one of the pulleys,particularly the crank (drive pulley),and file anything not correct-have you had the cam belt done recently?

quick update once everything was taken apart it turns out to be the pas pump

thanks for all the advice guys