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Belt Tensioner and Idler pulley bearings

7K views 1 reply 2 participants last post by  IlovemyFX 
#1 ·
I recently started to hear a bit of bearing noise coming from the tensioner pulley on the main serpentine belt. I checked with the Infiniti dealer in Halifax and the part is $481 + tax (CDN). I decided to pull the pulley and see if I could replace just the bearing. While I was at it, I decided to do the same for the idler pulley and Power steering (P/S) belt tensioner.

The main belt tensioner pulley is pretty simple. Just release the tensioner, with a 14mm socket and ratchet, and lock it in place with a long allen key. You do not need to remove the entire tensioner assembly, just the pulley. The pulley bolt is a 14mm but it is reverse thread, so you turn it clockwise to loosen. The idler pulley is also 14mm but is normal thread. You can leave the belt in place.

The P/S tensioner has to be removed as a complete assembly. Again, release the tension and lock it in with a allen key. There is a small plastic in the centre of the tensioner. It comes off easily with a small screwdriver or pick. There is a 8mm Allen bolt that holds the tensioner on. Just remove the bolt and take the entire assy out. You will see a plastic cover on the backside of the pulley. Remove it with a small screwdriver. Under that is a T30 torx bolt that holds the pulley to the tensioner.

Once you have all of the pulleys removed, you can either use a press to extract the bearings, or bring them to a maching shop for removal. You could also rig up some sockets and bolts for removal. I have a press, so this part was easy.

I found the following:

Idler pulley - uses to stacked NTN 301LU bearings. I used 2 X 6301-2RS bearings. They have the same dimensions.

Both tensioner pulleys use a single NSK 6203-2RS bearing.

All 4 bearings cost $25 total.

I pressed the bearings in and reinstalled the pulleys. The engine is once again quiet, other than the normal noise a 5 litre engine makes.
 

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#2 ·
Nice post Denis. Really good information here. Should probably be in the DIY section, if we still have one that is.
 
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