Ah this one I am having trouble diagnosing. I had an alternator put on my wifes 2002 maxima a few weeks back. I don't know why but when the car is first cranked, that alternator vibrates like a fool. So much so that it's evident in the cabin. When you go out, its a very fast twitch type vibration.

Also the belt squeels during the first few seconds of startup after an overnight teanure.

Would a somewhat loose belt cause the extra vibration.

I checked all the bolts and they are all snug.

 

Vibration will be caused by: 1. Bad mounting, loose bolts. 2. Bad bearings. 3. Wrong belt.

Go through each one, good luck.

 

Otherwise it could be your mounts.

 

If its indeed your alternator you may have a bad one. Best thing to do is to pull the belt off and feel for any roughness in the alternator or other accessories that are driven by the same belt. Another thing to look at is the belt itself. Make sure its not glased and is installed properly.

 

The bolt holding the pulley is most likely loose and you should replace the bolt with a new one in case it starting to strip.

 

Im experiencing somewhat of the same problem, no vibration but if there is then i can't really notice it. belt squeals during start up for a good 10-15 seconds then goes away.

Had a new high output alternator installed before this belt squeal started. Alternator came with a smaller pulley so the belt was also replaced with a shorter one. While installing alternator I managed to snap the adjuster bolt on the tensioner so i went ahead and replaced the whole thing with OEM from Nissan(tensioner/adjuster/nuts/washers).

I haven't got the time to go over everything and find the problem so i've been dealing with the squeals. One thing i did notice is that the tensioner seems to have a lil flex/movement to it if i move it with my hand.

I am thinking maybe the tensioner pulley wasn't installed correctly so i may need to check that but won't know the correct way to install it.

My A/C also stopped working, was told that theres a leak in the low pressure hose so can it be the a/c compressor making the squealing noise??