Back in a 4Runner after Land Cruisers for a while.

The bearing on my serpentine belt tensioner started making a lot of noise. Toyota Canada wants $352 for the tensioner pulley assembly on my 2003 (made in late 2002) 4Runner. The bearing itself if not available from Toyota or offered individually by parts stores when you ask for a tensioner pulley bearing for a 4Runner with a 4.0L V6. As I only replaced the bearing, I did not have to pull the AC and possibly alternator to access the tensioner assembly.

I pulled the bearing off the tensioner assembly. It is easy to do BUT know that the bolt is REVERSE THREADED (i.e. it is loosened by turning CLOCKWISE, opposite of normal). I found the bearing number on the bearing dust shield, it was hard to read but there. I phone a parts store and not only was the bearing available by part number, but it is a common one and they had 5 in stock. I don't even remember what I paid because it was so trivial a sum... like $15.

My built-in-late-2002 4th gen 4.0 V6 4Runner had an NSK 6203 DUL1. I think the 6203 is the bearing size, the DUL1 means its sealed both sides, but don't quote me on that. I'd assume most, if not all bearing-manufacturers (NSK, SFK, Koyo, Timken etc.) produce this size bearing. An auto parts or industrial supply store should be able to easily cross-reference this bearing. I used an SKF 6203-2RSJ bearing as a replacement.

Note that there maybe a different bearing size for 4Runners built after mid-2003, as identified in the VIN. Toyota parts shows several tensioner assemblies listed for 4Runners, depending on the year. That said, there will be a bearing number somewhere on the OEM bearing that can be cross-referenced.

Removal, repair and install procedure

1. remove engine cover to free up working space (2x 10mm bolts)
2. Place 14mm socket on tensionner and turn counter-clockwise. This will let tension off the serpentine belt. While slack, pull the belt off the power steering pump.
3. With the same 14mm socket, unscrew the bolt on the tensioner in a CLOCKWISE direction (reverse threaded bolt).
4. Remove the pulley wheel. The bearing is pressed inside the pulley wheel.
5. Either press out or hammer out the old bearing. You won't be re-using it, but not obliterate the numbering so that you can ID it.
6. After removing the bearing, place place the pulley wheel in the oven (I did 300* for 10 min.). Skip this step if you have a press.
7. Smear oil (engine oil... or anything really) on the outside of the bearing and press into the pulley. I tapped mine in carefully with a peice of copper plumbing pipe serving as a punch until fully seated in the pulley.
8. Install is the opposite as the removal.

Found these threads useful:
http://www.fjcruiserforums.com/forum...ml#post1888318

Idler Pulley/Bearing Failure, what to do: - Toyota FJ Cruiser Forum

Serpentine belt pulley diagram for a 1GR-FE V6



Serpentine belt tensioner is visible on the bottom left of the photo



Replacement bearing: an SKF 6203-2RSJ.



The tensioner pulley, with its faulty bearing on the left, and its replacement on the right. The original (OEM?) was NSK 6202 DUL1 bearing on my truck. I replaced it with a SKF 6203-3RSJ. Varies by year possibly.