Serpentine Rattling

[FATHERnSON]

So I had been hearing a bit of a rattle under the hood at idle for quite some time, but it's gotten to be very loud and concerning. I narrowed it down to the passenger side of the engine, and when I run the engine without the serpentine belt the noise goes away. The only part of the drive belt system on that side of the car is the alternator, and when I fiddle with it the actually pulley has a little bit of play left right and in out. Is that what it is? If so, can I fix that without buying a new alternator? If that's not the issue does anyone have any advice on where to look? Its a 3.0 V6 by the way.

 

[Uncle Gump]

Are you sure it isn't the tensioner or idler pulley? Those are known to get noisy with some mileage.

 

[ericbphoto]

Alternator pulley should have no play left to right or up and down. A bit of end play could be ok. Its easier to replace the alternator than to rebuild it yourself. Does it rotate smoothly by hand? Also look at the rear of the alternator. I had the rear bearing walk out of place on mine once.

I agree with Gump. Check your idler pulley and tensioner pulley. Check for excessive play and make sure they rotate smoothly.

 

[FATHERnSON]

After some more research I was going to look at the idler pulley and belt tensioner today, but I heard/saw rattling on the passenger side and those two were on the other side I thought. Also after some more reading I'm hearing that lose belt pulleys result in some nasty squealing; I don't have any of that. The bearing on the alternator shaft is still there.

 

[FATHERnSON]

It was the alternator pulley. I just went and picked up a new one at the local pick n pull so she's back to just normal loud lol.