Four (4) customer questions are discussed in this bulletin regarding the proper timing belt tension on the Audi and VW 4.2L engine as used for the models shown below. 

Audi A6 Timing Belt Kit - 2001-04 w/ 8 Cylinder 4.2L Engine Code AWN 
Audi A8 Timing Belt Kit - 2001-03 w/ 8 Cylinder 4.2L Engine Code AKB or AUX 
Audi A8 Timing Belt Kit - 2004-06 w/ 8 Cylinder 4.2L Engine Code BFM or BGK 
VW Phaeton Timing Belt Kit - 2004-06 w/ 8 Cylinder 4.2L Engine 
VW Touareg Timing Belt Kit - 2004-07 w/ 8 Cylinder 4.2L Engine 
Part Numbers: GH21118, GH21118-1 

audi vw v8 timing belt tension

Question 1) The instructions for installing the kit leaves the timing belt so tight it appears to bind the water pump and hydraulic damper. Will this create potential failure of these parts? Should the tension be loosened a bit?

Answer: Please note steps 25-28 in our instructions related to setting correct Audi or
VW 4.2L timing belt tension correctly: 

25) Insert a 5mm drill bit between the hydraulic damper piston and the tensioner pulley casting arm. Allow the tensioner pulley casting arm to rest on the 5mm drill bit. (Image 9) 

26) Using eccentric tool T40009 rotate eccentric tensioner pulley counter clockwise until the arm of tool T40009 is aligned with the center of the water pump pulley and torque to 16 ft lbs. (Image 10) When doing this step make sure the 5mm drill bit is still properly in place as outlined in the previous step.

 27) Remove the 5mm drill bit from between the hydraulic damper piston and the tensioner pulley casting arm. 

28) Compress hydraulic damper, remove damper holding pin, and allow damper to un-compress. You will want to allow the hydraulic damper to un-compress thoroughly for best belt tension. 

Note 1) After removing the damper holding pin, a 5-7mm distance between the top of hydraulic damper body and the tensioner pulley casting arm should be maintained. 

audi vw v8 timing belt tension and tool
Note 2) The belt tension will be tight. After the crankshaft lock pin (Step 32) has been removed and the camshaft pulleys torqued to spec, rotating the engine two full revolutions by hand. This will allow the new timing belt to center, align, and properly relieve any binding of the belt that might exist. As described in our Audi VW 4.2L timing belt instructions, the distance between the top of the hydraulic tensioner damper body and the cast tensioner lever arm should be 5-7mm after rotating the engine by hand two full revolutions.

Question 2) Does having tight 4.2L V8 timing belt tension effect the longevity of the timing belt components? 
Answer: If you use official O.E. specification timing belt components and you follow the steps as outlined above the answer is NO. These components are engineered and design to perform under load. All BLAU 4.2L V8 Timing belt kits contain official O.E. timing belt tensioners and belts. These are the same O.E. tensioners as those directly supplied to the O.E. automotive manufacturer. That means they are designed and engineerefor the exact same specifications and life span as O.E. and will last as long as the genuine components you buy from the dealer.

Question 3) Does tight 4.2L V8 timing belt tension effect the longevity the water pumps you use? 

Answer: The Graf O.E.M. water pumps used in our kits have been engineered with a large enough displacement sized OEM bearing to carry the heavy load that the timing belt is applying to it. With proper timing belt tension procedures followed the water pumps are designed to exceed the factory service intervals. 

Question 4) Does your kit contain aftermarket belts? 

Answer: The INA - Gates 4.2L V8 timing belt in these kits should NOT be considered 'aftermarket'. INA - Gates is an OE supplier to many automotive manufacturers for a variety of models. 

We would like to encourage installers to read the entire instructions ahead of time and then to take the time to correctly follow the instructions for a failure-free installation. If you have unanswered questions during the repair process, feel free to contact us.