Got this 2002 Ford Escort 2.0L. My problem is that the belt tensioner keeps bouncing back slightly making a clattering noise (not too bothering... but noticeable) Its as if the belt tensioner doesn't have enough tension and the belt force keeps forcing it back....to make it bounce a little back... then back to position. I replaced the belt and
Remove the belt and check each of the accessories and idler pulleys to make sure each spins smoothly without any play laterally or axially. Check each pulley surface to make sure there are no bumps or gouges. Check the crankshaft pulley to make sure the damper isn't breaking down (just watch it as it spins and make sure it's not bouncing around). If the tensioner bounces more when the A/C is engaged, that's normal.
The tensioner on my 97 Escort bounces around a little, and there's no reason not to live with it as is. But it doesn't make a clattering noise, or at least I can't hear it over the usual valve train noise.