bushing inside the bearing of idler/tensioner pulley - loose and noisy

[jbutler67]

Mercruiser (5.0l / 5.7l Alpha & Bravo Gen+) - M048938

Engine making a clickety clack noise while running. I located problem -- idler/tensioner pulley. I removed serpentine belt and started engine again (for very short time). Noise gone.

I spun all the pulleys and narrowed it down to the idler/tensioner pulley. Bearing inside the pulley spins fine. But, the bushing inside the bearing is loose, has a little slack, it's not snug. I purchased a new bushing thinking the existing one may have worn down over time.

The new bushing has a little slack too, it's not snug either.

Questions
1) Should the bushing inside the bearing have a little slack? Or should it fit snugly? (If it should fit snugly, then inner diameter of bearing may have worn down?)

2) is there a way to make it fit snugly?

3) what diameter idler/tensioner pulley SHOULD be on model M048938? 3" or 4.25"? Closed cooling, power steering.

Currently has one that is 3" diameter.

Thanks for your help.

 

[Bt Doctur]

 

[jbutler67]

Here is a view from further back...

 

[achris]

What condition is the bearing in? That would be the first thing I would replace. There should be a number on it, or just remove it and measure it up and get a new one from a bearing shop. I would expect those bearings to be so expensive you'd get a dozen for under $10...

Chris.........
(DO NOT buy it from Merc.... You'll pay the 'marine' tax. )

 

[jbutler67]

Bearing number is NTN 6203LH. Pulley is a Dayco 00076.

Bearing spins fine and no noise. (But, that doesn't mean the internal diameter is worn.)

 

[achris]

Bearing number is NTN 6203LH. Pulley is a Dayco 00076.

Bearing spins fine and no noise. (But, that doesn't mean the internal diameter is worn.)

Yep, just pulled the pulley off my engine and the bushing is a CLOSE fit, and that's the same number for the bearing...

Chris.....

 

[jbutler67]

Yep... it's the bearing.

Internal diameter should be 0.6693 in or 17.000 mm. The current one is 0.688 in or 17.5 mm. Plus.... the "new" bushing I received by mail is only 16 mm!

 

[achris]

Closer inspection of the pulley, and I don't think the bearing is removable. (I think the pulley is manufactured around the bearing)... The good news is it is a Dayco pulley, and Dayco have a size chart. Just measure the pulley and look it up on their chart.... http://www.daycoproducts.com/dimensional-guide-and-catalog-pdfs And click on 'Pulleys'...

Chris.......

 

[jbutler67]

Thanks Chris!