WHAT VEHICLE? WHAT ACCESSORIES DOES THAT BELT DRIVE?I replaced my serpentine belt with a new gates belt. The new belt immediately started a clanking type sound. Researched a bit and decided to replace the tensioner and also the idler pulley. Put belt back on and the noise is still there. Odd thing is, I put the old belt back on and the clanking goes away. What’s my next step? I’m out of ideas. Thanks for any insight.
There was a time when CS130 alternators were an epidemic-failure item. Generally the rear bearing. When one died on me, it locked-up so bad the starter couldn't crank the engine until I pulled the belt off.
Similarly, the R-4 compressor was known to explode internally (which you'd know by now) or the pulley bearing would go rough and have slack.
The symptoms you're describing could be a failure in ANY of the accessories--PS, AIR pump, water pump/fan clutch, etc.
They could also be a pebble stuck in the rib of the belt, or maybe a pebble stuck in the rib of a pulley.