I have a 2000 Dakota 3.9L standard cab with 60000 miles on it. The Serpintine belt squeals and apears to be slipping on the alternator. The pully on the alternator is all rusted! Is this rust causing the belt to slip? Will a new belt fix this or can I change the alternator pully or paint the pully to correct the slippage??

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If the belt is tight, I don't think some rust would cause it to slip unless it's rusted so bad the diameter of the pulley changed. You could always take the belt off, take a wire brush and clean up the pulley and see how it is after that. If the belt is loose then you probably need a new belt.

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1999 v-6 solar yellow 4x4 sport ext. cab.

If it's the same belt as on the V8, then yes in my experience they do start to squeal after 20 or 30k miles, it's worse when its cold or humid out. Easy replacement. Never seen a rusted pulley like you mention, if you have it pulled to clean up just be sure the surface of the pulley is smooth, any roughness will year the new belt like sandpaper.

This happed to me about a year ago. Check your accessories. Rumor has it that water from the under chassie spray at the car wash gets into the bearings of the assessories and washes out any grease. In my case it was the alternator.
Hope this helps.

Had the same thing happen to me, although my alternator pulley was not rusted. Mine was the belt tensioner pully. I changed that and all was fixed. It had rusted to where is was not auto-adjusting the tension.

Hope this information was helpful.

Mike

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MM

I have a '97 Dakota with the 3.9. It seems to squeel most when it's first started, when it's hot & humid, or when it gets wet from rain. I have already replaced the belt twice, replaced the tensioner pully, and replaced the idler pully. Every time I replace something it stops for a few days then goes right back to squeeling. I've tried belt dressing and it makes it far worse. The only thing that quiets it down for awhile is a bar of soap, but you have to do that every time you start it because as soon as you shut off the engine for awhile and restart it, it's squeeling again. I've even tried taking a wire brush to all the pullies. I have no idea where to go from here and it gets really old putting soap on the belt everytime I have somewhere to go. Any ideas?

check your accessory pulleys for junk in them. make sure they are turning ok and not seized.

I've taken a wire brush to all the pullies. The roughest lookin pully is the alternator pully and my next attempt to fix will be trying to get a little bit of rust off that one. I'm not really sure that will do anything though because I have put the wire brush to it before and even though there is a hint of rust on it, it's not really on the contact point for the belt.