Hi,

Had to replace alternated two days ago. I went ahead and replaced the serpintine belt while i was at it and tried to charge the AC.

Everything worked fine until after I charged AC. Once the AC cycled on the tensioner pulley started knocking. Ended up replacing the tensioner and pulley.

Everything great for a day -took on freeway no problem. Today knocking sound is back though not as loud as before.

Noticed the gap on the top of the tensioner is reduced from what it had been after initial installation...

Any idea what's up?

PS- I have not turned on AC since the initial test after charging it (still blew warm).

 

Have had bad "new" tensioners. If it was an economy version could be tensioner.
Sometimes an engine problem will show up as vibration/ noise from belt tensioner.
How does the pulley alignment look with the alternator you installed ?

An overcharge of refrigerant or too much oil in the A/C system can place a load on the belt and tensioner.