I just changed out my altenator and put on a new belt... Belt/pulley still has a squeal to it. Two questions, is it possible to over tighten it and what would be the effects be, also how can I tell if my pulley is bad? My mech buddy suggested that could be the issue. If the pulley is bad do I just need to get a new one, take off bolt, washer and pulley to replace?? TIA...

 

I broke mine when I changed my UDP. If you go to Nissan it should be around $40- they will give you the pulley, the washers and bolt with nut. Probably the only way you will find out if you've gone too far is when it breaks. or starts tightening up alot. That's what mine did and then the bolt snapped.

 

You can easily overtighten it. You will hear an annoying
noise.

Adjust the the tension first and see if the sound goes away.
If it's still there you can take the belt off and start the car
just long enough to hear if the noise is there.
If the noise goes away chances are the bearings are going on the
pulley and you will have to replace it. Mine didn't go till I hit
290,000KM.

 

Thanks for the suggestions... One quick question though, do I have to loosen the nut on the pulley ar can I just tighten the tensioner?

 

Yes, you have to loosen the bolt that is in the center of the pulley before you can effectively tighten or loosen the bolt that goes down in behind the pulley. They both should be 14mm.

 

Bolt on the idler pulley is 12mm. Bolt on the unit that moves it up/down is 14mm.

 

In addition to the other suggestions, apply pressure on the belt, around mid-way between the pullies. If the belt gives more than 1/2", you need to adjust it and make it more tighter.

 

If you have the belt off, check the ac compressor bearing and see if that pulley makes any noise when you spin it.