VW MK4 How To Remove The Serpentine Belt Tensioner And Lube The Pulley Bearing In A VR6

Overview

Thanks to VgRt6 from the ‘tex for this DIY that explains the procedure for removing the serpentine belt tensioner from a VR6 engine and lubricating the tensioner pulley bearing.

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It’s 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 lubrication 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, lubricating the bearing with a few cents worth of grease before bearing failure can prevent you from having to (1) purchase a whole new OEM tensioner unit for $100-200 (depending on where you buy it from), (2) purchase an aftermarket pulley for $50-100 or (3) buy a new bearing and spending the time and/or $$$ to install it in the existing pulley. The procedure below is very simple and should take around a half an hour to complete.

Tools

Here’s a list of recommended tools to complete this job:

1) 3/8″ drive torque wrench (capable of measuring 18-30 ft/lbs)
2) 3/8″ drive ratchet
3) High-temp wheel bearing grease or other suitable lubricant
4) 15mm socket (3/8″ drive)
5) T30 Torx socket (3/8″ drive)
6) Small flat-head screwdriver
7) M8x1.25 pitch bolt, about 2 or 3 inches long. (I have not specified an exact length since it varies depending on the model year/version VR6 you have)
8) 6mm Allen socket (if the bolts on your VR removed in Step 5 are this type)
9) 13mm socket (3/8″ drive)

Parts

There aren’t any parts required for this project.

Instructions

DISCLAIMER: No warranty or guarantee is provided for the information provided on this site; you use it at your own risk. Although contributors to DIYNexus have an impressive depth of knowledge, neither they, nor DIYNexus can be held liable for any technical inaccuracies, typographical errors or consequences from the use of this information. Depending on the project, it is possible to void your factory warranty, disable a safety feature, create a hazardous condition, be injured or killed. 🙁 If you are uncomfortable or inexperienced working with anything described on this site, please consider having the work done professionally.

REMOVING THE SERPENTINE BELT TENSIONER

1) The serpentine belt tensioner is located on the passenger’s side of the engine, under the cover indicated by the arrow in the picture.

2) Remove the long cover piece on the passenger’s side of the engine to reveal the tensioner. To do this, remove the two (2) T30 Torx screws (indicated by the red arrows in the picture) and carefully pull up on the cover piece.

3) Here’s a general pic of the area we are working on. The serpentine belt tensioner is indicted by the yellow arrow and 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 M8x1.25 pitch bolt into the threaded hole in the top of the tensioner unit (as indicated by the red arrow in the picture) and turn using the 13mm socket until the serpentine belt is loose. Basically, you’ll need a bolt that is long enough to fully remove the belt tension before the bolt threads in completely, but is short enough to not interfere with the fuel lines overhead. The author recommends that you purchase a few bolts with different lengths and return the ones that don’t work.

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 arrows in the picture. NOTE: On some cars, these bolts will be 6mm Allen instead. 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.

NOTE: If you do not plan on lubricating the pulley bearing and reinstalling the tensioner back onto the engine right away, the author recommends 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.

LUBRICATING THE TENSIONER PULLEY BEARING

6) Using the 15mm socket and ratchet, remove the pulley from the tensioner arm by removing the 15mm bolt. NOTE: THE BOLT IS REVERSE THREAD. TURN IT CLOCKWISE TO REMOVE!!!

7) This 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.

8) Use a small screwdriver to remove the seals from each side of the pulley bearing, as shown in the picture. To do this, insert the screwdriver between the seal and inner race and VERY CAREFULLY pry the seal upward. Make sure you do not damage the rubber coating on the seal or it may not stay in place when reinstalled.

9) This picture shows the tensioner pulley with both bearing seals removed.

10) Pack each side of the bearing with some high temp. wheel bearing grease or other suitable lubricant, as shown in the pic. (You may want to use slightly less than shown here based on feedback from others who have used this DIY) You can also add a drop or two of oil to thin out the grease if it’s very thick. Once the bearing has been packed with grease, carefully reinstall the bearing seals. MAKE SURE THAT THE SEALS ARE INSTALLED FULLY OR THEY WILL WORK THEMSELVES LOOSE AND WEAR AGAINST THE PULLEY GUARD OR TENSIONER ARM WHILE THE PULLEY SPINS.

Now you’re completely done with the disassembly and lubrication procedure!

Replacing the pulley and tensioner is basically an “installation is reverse of removal” task. A few things to note:

• Remember that the pulley bolt is REVERSE THREAD – turn it counter-clockwise to tighten.

• Use the torque wrench to torque the tensioner-to-engine bolts to 18 ft-lbs.

• There is no ‘official’ torque spec for the pulley bolt but 30 ft-lbs should be appropriate.

• 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.

NOTE: For those interested in replacing the serpentine belt, this illustration shows how to route the belt around the various accessory pulleys.

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