Belt Tensioner: Bearing 203

Belt Tensioner Problem: Bearing 6203

Serpentine belt tensioner and idler pulley field repair; quick fix for noisy or worn-out bearings 


by Bruce W. Smith

The old saying, “The squeaky wheel gets the grease,” really does apply when it comes to those serpentine belt-tensioners and idler pulleys that help drive the power steering pumps, A/C compressors and alternators on our pickups. 

Automatic belt-tensioners (and idler pulleys) are used on millions of vehicles and extend the life of today’s serpentine belts beyond 100,000 miles.

But the bearing the tensioner’s pulley rides on might not last as long.

If your pickup has developed an annoying squeak that’s coming from the front of the engine, or it’s thrown a belt, chances are good the culprit is the bearing inside tensioner’s pulley — not the tensioner.

Most pickup owners and many fleet service managers think the tensioner pulley or idler pulley is maintenance-free or non-serviceable item that hs to be replaced as a unit.  It’s not.

This little bearing can save you $60 in repair costs and serve as a quick field repair.

While it’s probably best to swap the old tensioner assembly with a new OE replacement, you can replace the pulley bearing and save  $50 or $60.

The sealed bering is very common: NTN 6203 or Timken 203FF. It’s used in alternators, clutches, idler pulleys and even lawnmowers. 

It’s a $6 part  that can be easily installed in the field or in the shop.

If nothing else, toss one in the toolbox. Replacing the bad bearing in the old tensioner gives you a cheap “field backup” just in case the problem happens on a jobsite or in transit.