on my 86 k 5 blazer the alt. is giving me trouble when you start it you have to let the volt meter get over 12v before you move or the belt will slip and squeal i have had to replace the belt several times and i swapped the alt out with a used one and a new one with the same result. everything about it is stock set up except the big wire off the back of the alt. is now ran strait to the battery because it melted the fuse link at the fire wall and i had to fix it on the side of the road that was 5 years ago it started the belt squealing 2 years ago granted the truck dosnt see 5000 miles a year

i checked the voltage and i have power on the wire to the batt at all times(of course) and the bigger wire on the plug (red) key on or off


what ya think?

sometimes it happens because of crappy belts from discout stores(thin offshore crap) try a better quality belt like from NAPA or CARQUEST they may cost more but they generally fit in the groove better

I second cdowns idea. A good belt (Gates is the best, IMO) is gonna cost ya about twice the price of a wallie world belt. But, it should end your squalling problem.

I had a similar situation with a serpentine belt on a '95 350 sbc that I had. I put 3 different Kelly belts on it from AutoZone and all three squealed and would jump out of the grooves. I got scared thinking that a pulley was bent or out of alignment or something. After about 2 weeks of this B.S. I bought a new Gates belt and it never gave me a bit of trouble.

no i have used 4 gates and 3 dayco i asure you it is not a belt quality issue the alt. is not prejudice it will burn up cheap or exspensive belts. like i said it has to do with when the voltage gets to 12 on the gauge before 12 it will squeal till it burns over 12 its fine???

Now, I'm thinking cheap alternator (it is squalling when it has a load on it, it seems).

beat me to it shadetree,sounds like the alt bearings are raising heck under load..

Give the battery a good check & check for a small drain overnight. Seems like you have a strong load on the alternator till the battery comes up a little. Sometimes a replacement alt. is higher amps than the original & will put more load on the belt. When the same belt is driving a smog pump it was a big problem back a few years ago till most of the smog pumps were taken off. With the smog pump it left very little contact area for the belt on the pulley. This contact area is important. Sometimes you can use a longer belt if the adjustment slot will alow it. The belt must be very tight along with the other belts. They help by driving the other accessories & takes some load off the aly. belt. Another thing to look for is a bad or wrong fan clutch. A larger alt. pulley might help also.

well at least i know my first thoughts were the same as yours the squeal is also not prejudice about alt. it has done this with 3 alt the original 90 amp the 60 whatever amp off my 81 and a new 90 amp

as far as the battery goes it is a fairly new optima yellow top and as far as a draw it dosnt matter if it sits 5 months, over night or 5 min in the grocery store it always does it when you start and if it falls low enough at idle it will do it again but mostly only at start up

post a picture of this alt with the belt installed looking at the next pulley..

a pictures worth a thousand words :metal: