How to replace a noisey belt tensioner bearing in Land Rover 300tdi

Replace the 300tdi tensioner bearing and stop that squeeking belt!

Replace the 300tdi tensioner bearing and stop that squeeking belt!

The bearing in the Discovery, Range Rover & Defender 300tdi fan belt tensioner is a common failure item.  It starts as a minor squeek and soon starts to becomes a loud repetative chirping. Mine had began to sound like I had an angry budgie under the bonnet.

This 300tdi fanbelt tensioner bearing is available on eBay.  The information below shows how I replaced mine recently.  The very first thing you need to do is remove the top piece of fan cowling in order to gain a bit more access.  

Replace 300tdi tensioner bearing

Next you need to take the tension off the belt and get the belt out of the way of the tensioner.  Use the longest 15mm spanner you have on the nut on the tensioner pulley wheel.  A bit of pressure anticlockwise will lift the tensioner from the belt and allow you to free the belt from the tensioner.  

Once the belt is out of the way you need to remove the tensioner pulley (complete with squeeky 300tdi tensioner bearing).  This bolt is left hand thread so you need to turn it clockwise to undo it.  Once you have the pulley off and the bolt removed, you will be able to see the offending bearing in the centre that causes that famous 300tdi fan belt tensioner squeek!  

300tdi tensioner pulley removed 

The bearing in the 300tdi tensioner pulley can only be removed from one side (from the front as it was originally fitted to the car).  You will see there is a snap ring that needs to be removed first.  This can be a real nitemare to get out, its a tight fit at the best of times.  It will come out with a bit of effort.  The picture below shows it removed.

Snap ring removed from 300tdi tensioner

The tensioner I was working on when I took these pics had previously had a bearing replaced.  Whoever did the last one clearly had a nitemare removing the snap ring (they can be very difficult to get out).  They have drilled a hole in the tensioner pulley that allowed a small screw driver to be inserted behind the ring – this made it really easy to remove.  I suppose this is bound to weaken the pulley slightly but it has been on this car for tens of thousands of miles without a problem!  Its up to you which way you do it but I have included a picture of the drilled tensioner pulley (with the bearing removed).

300tdi tensioner pulley drilled to help remove snap ring

Once the snap ring is out, its a simple job of pressing the old bearing out and the new one in.  You don’t need a bearing press for this, its easily done in a small vice. I would think that with a bit of thought, this could be done with a large G clamp!  I just used a small workshop vice and a socket that was almost the same size as the bearing.

Pressing out300tdi tensioner bearing with a vice

Once your new tensioner bearing is fitted , you just need to refit the old snap ring.  This is a bit fiddly but is a great deal easier than removing it.  Once that is back in you are ready to put it back on the car.  

tensioner puller from 300tdi discovery complete with new bearing.

Here is my 300tdi tensioner pulley complete with new replacement bearing:


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