Cars with VAG 1.4 gasoline engine: Do you experience noise from the water pump?

On vehicles with VAG 1.4 gasoline engines, you may occasionally experience noise from the water pump. The noise usually leads to the conclusion, that the water pump should be replaced. However, it is by far not all cases where this is necessary.
 
The vehicles covered by the problem are equipped with a special water pump that has two pulleys. The inner pulley, which operates the compressor, is switched on and off as required, while the outer pulley keeps rotating once the engine is running. The activation of the inner pulley is carried out by activating an electromagnet that connects the two pulleys via a spring-loaded flange mounted on the outer pulley. On the inner pulley, the contact surface of the flange is provided with a clutch / friction ring.  
 
 

The noise that can occur whether a Triscan- or OE pump (Triscan ref. 860029062) is used, is often heard at a certain rotation speed. If this is the case and the cooling of the engine is working properly - and the water pump does not show any visible signs of leakage or clearance - it is our experience that the noise is generated by the spring-loaded flange of the water pump.

The noise is caused by vibrations propagating in the water pump's outer pulley and causing the spring-loaded flange to vibrate at a certain rotation speed. The clearance between the two flanges is just a few tens of millimeters, and therefore the contact surface of the vibrating spring-loaded flanges can unintentionally hit the contact surface of the opposite flange, causing noise.

It is our experience that the vibrations often stem from the v-belt drive system, for example, a defective belt tensioner or a misalignment in the system. Instead of changing the water pump, the troubleshooting should focus on finding the true source of the vibrations.


The noise stems from vibrations causing the contact surface of the spring-loaded flange on the outer pulley to hit the contact surface of the flange on the inner pulley
 

The noise can occur on cars with the following engine type (11.2005 - 08.2015):

  • 1.4 FSI with engine types CAVB, BLG
  • 1.4 TSI with engine types CAVA, CNWB, CTHA, CAVF, CNUB, CTHF, CTJB, CAVD, CNWA, CTHD, CTKA, CAVC, CTHC, CTHB, BMY, BLG, BWK
  • 1.4 TFSI with engine types CAVG, CTHG, CTJA
  • 1.4 TSI RS with engine types CAVE, CTHE
  • 1.4 GTi with the engine types CAVE, CTHE

within the brands Audi, Seat, Skoda and VW. For more information about the car models and specific years: Enter 860029062 in Triscan's TriWeb (Ref. List).