PROTIPS from Blue Print: Timing belt tension pulley

15 Apr 2023

Cars with 2.5 and 3.0 TDCi diesel engines, such as the Ford Ranger and Mazda BT50, are experiencing a problem with weak or insufficient timing belt tension after replacing the tension pulley. What to do in such a situation?


If, when installing a new tension pulley, you find that it shows no resistance, bleed the pressure chamber according to the following procedure before installing the timing belt.


  • Install a tension pulley in the engine.
  • Using a suitable tool, turn the tension roller with a torque of 39 Nm or less, and then slowly turn it in the opposite direction.
  • This operation should be repeated several times.
  • Make sure that the piston rod shows resistance in the mounting position.
  • If there is still no resistance from the roller, repeat the procedure.

Once you are sure that the tension pulley is working properly, you can continue installing the timing belt according to the vehicle manufacturer’s recommendations.

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