another squeeky belt

I know squeaky belts aren't a new topic here but I haven't seen this exact situation yet so here goes...

Couple weeks ago I start hearing a squeak coming from the front of my Blazer. I noticed the tensioner is moving a lot, so I replaced that along with the belt. Squeak went away, and I thought the problem was solved.

Couple of days later, it comes back. I check the tensioner...looks ok. Water pump looks ok-nothing in the weep hole & the pully feels solid. Can't isolate just where the noise is from. Also cleaned the grooves in all the individual pulleys.
So, just for giggles, I put the old belt back on (it was only a few months old to begin with)...& magically the squeek goes away for a few days, but eventually comes back.
I've gone back and forth probably 6 times now using the same two belts..squeeks, change the belt, it's quiet for a couple days then comes back until I swap belts again.
This is drivin me nuts...any ideas?
-Mike

have the same thing on my jimmy... seems like the belt is sticking to the pulleys... bust out the ol bar of soap and rub a little on the grooved side... temp fix but it works

dont put soap on it, that will help the belt fly off, what kinda belt and tentioner is it and where did they come from? i reccomend goodyear belts and gm tentioners to all my customers because i trust them to test my liability

You said the tensioner was moving some . What you describe sounds like this. when you remove the belt , the tensioner relaxes off the spring . It might pick up some lubrication internally and when you put the belt back on , the squeeky surface has lube on it . Then after a few days that lube wears off with that tensioner movement .
While the belt is off , shield everything and carefully spray some heavyweight oil ,not Wd40(too light and dries out) inside the tensioner spring . Rob

How about the idler pulley fixed mounted above the water pump - that bearing often goes bad too. Then of course the famous GM alternator bearings start going and you get that same noise so with the belt off the alt spin it and see if it grinds or grates alittle - pull in and out on the pulley and see how much play you have - thats been my fix on many Blazers - new alt about $150 at most stores - get new for $10 more!

thanks for the replies;
I'm gonna check the idler pulley next. The tensioner was replaced after I found the old one shimmying around a bit, & the alternator is only about a year old, though that doesn't mean it couldn't be at fault of course.

If I can add a dumb question for the same price....what is the pulley/device that's directly under the water pump?
I know all the other stuff that the belt drives, but I can't place what that one is.

thanks guys!

Thats the harmonic balancer that is the drive for the belt -its connected to the crankshaft.

My money is on the idler pulley.

Has any pulley been replaced recently, other than the tensioner? You mention the harmonic balancer(the pulley under the water pump), if that was taken off for any reason, and not reinstalled fully back on the crankshaft, or reinstalled but the large bolt not torqued right, then the balancer will walk out a little, causing the pulley on it to be off a little with the rest of the other pulleys in the belt system, giving you that belt noise. The same can happen if the power steering pulley was removed and not replaced fully back on the pump shaft.

I can't pinpoint sounds worth a damn but it kinda comes from the area by the idler pulley. I'm gonna replace it next day or so to see.

I just asked about the harmonic balancer, 'cause I wasn't sure what it was seems to be tight & in line with the rest of the pulleys.

As for the other pulleys, the tensioner has been on for about 4 months, the alternator, I believe is a year or two old, & the AC unit is about two years old, the others are original equipment (1997)

I looked at it again today & I did notice just a little front-to-back play on the power steering pump pulley, maybe a millimeter or two of travel; everything else looks tight. gonna keep an eye on the power steering...might be my next project...

thanks again for all the help guys
-Mike