VR6 belt tensioner pulley repair

From THE Corrado Forum Knowledge Base

Contents 1 Removing a VR6 serpentine belt & tensioner and replacing the tensioner pulley bearing 1.1 You will need the following: 1.2 So let's begin 1.3 REPLACING THE TENSIONER PULLEY BEARING

Removing a VR6 serpentine belt & tensioner and replacing the tensioner pulley bearing

You will need the following:

The tools/parts needed to perform the procedures are:

1) T30 Torx driver
2) M8x50x1.25 pitch bolt.
2) 13mm socket or wrench
3) 15mm socket or wrench
4) Small screwdriver
5) Large heavy duty vice
6) Replacement NSK bearing part no. 6203-2RS1 (available from BSL for £6.70inc VAT)
7) Stanley Knife
8) Patience :o)

So let's begin

The following outlines the procedure for removing the serpentine belt tensioner from a VR6 engine and replacing the tensioner pulley bearing. It is common for the bearing in the pulley to dry out, causing the bearing to become very noisy when the engine is running and eventually, to fail. The replacement of the bearing as preventative maintenance or at the first sign of noise can significantly extend the lifetime of the tensioner pulley. Since VW does not sell the pulley separately, replacing the £5 bearing before it fails can prevent you from having to purchase a whole new OEM tensioner unit for £160.

REMOVING THE SERPENTINE BELT TENSIONER

1. The serpentine belt tensioner is located on the driver's side of the engine.

2. Remove air box. Undo the 3 rubber bands and disconnect the air flow plug. Air box just lifts out

3. The serpentine belt tensioner is indicted by the yellow arrow in the picture below. The tensioner pulley which applies force to the serpentine belt is indicated by the red arrow.

4. To remove the tension from the serpentine belt, thread a M8x50x1.25 pitch bolt into the threaded hole in the top of the tensioner unit (as indicated by the yellow arrow in the picture below) and turn using a 13mm socket or wrench until the serpentine belt is loose. You need a bolt that is long enough to fully remove the belt tension before the bolt head threads in completely, but is short enough to not interfere with the fuel lines overhead (red arrows in picture).

5. Once the belt tension has been removed, remove the tensioner unit from the engine by removing the three (3) 13mm bolts indicated by the yellow arrows in the picture below. When the three bolts are out, slide the serpentine belt towards the passenger's side of the car and off of the tensioner pulley. You should now be able to remove the tensioner unit from the engine.

6. Now jack the car up and remove the offside wheel and wheel arch liner to expose the lower pulleys. Remove the old belt and fit the old one. It’s a bit fiddly but I found it easiest to fit the new one from the top down.

NOTE: If you do not plan on replacing the pulley bearing and reinstalling the tensioner back onto the engine right away, I recommend that you remove the M8 tension-release bolt to release the extra tension from the spring inside the tensioner. While not likely, it's possible that the spring may be damaged or deformed if it sits for too long in an over-tensioned state. If you do remove the tension, make sure to thread the M8 bolt back into the tensioner and reapply tension to the spring before reinstalling the tensioner onto the engine. If you don't, you will not be able to get the serpentine belt back onto the tensioner pulley.

REPLACING THE TENSIONER PULLEY BEARING

7. The picture shows the three main parts of the tensioner unit - the main body, the spring-loaded arm and the idler pulley.

8. Remove the pulley from the tensioner arm by removing the 15mm bolt indicated by the yellow arrow in the picture (shows the bolt partly removed). NOTE: THE BOLT IS REVERSE THREAD. TURN IT CLOCKWISE TO REMOVE!!!

9. The picture shows the pulley removed from the tensioner unit. Note that there is a pulley guard (top center of picture) that is used between the bolt and pulley.

10. Cut around the retaining lip on the pulley (outlined in red). You have to cut pack quite a bit and you need a good sharp stanley knife. Cut back enough so you can see the outline of the bearing. It is important you cut back enough otherwise the pulley will split when you push the bearing out and trust me…you don’t want that to happen!!

11. Use a good sized socket and the vice to push the old bearing out. I used a bit of wood as well to minimise damage to the pulley. I only got it half way out with the vice and had to finish it off with the same socket and a big hammer!

12. Once its out, clean up the pulley with the knife to remove any lip that may still be there. This will make fitting the new bearing a lot easier

13. Fit the nice shiney new bearing (shown below) using the vice and socket again. Install the onto the tensioner unit and then reinstall the tensioner unit back onto the engine by following steps 2-8 in reverse. Remember that the pulley bolt is REVERSE THREAD - turn it anti-clockwise to tighten. If you have a torque wrench, the torque spec for the tensioner-to-engine bolts are 18 ft-lbs. I could not find the torque spec for the pulley-to-tensioner bolt, but 30 ft-lbs should be appropriate.

15. After reapplying tension to the serpentine belt and BEFORE starting the engine, check to see that the belt is properly positioned on ALL of the pulleys that it contacts.

For those interested in replacing the serpentine belt as well, the illustration below shows how to route the belt around the various accessory pulleys. (The diagram shows the route for cars with the optional AC, so uses a double-sided V-belt)

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