Alternator belt squeaks at startup when engine is warm, not sure why?

[dbsoundman]

Hey all, this may strike you as silly, but I have an annoying problem with my alternator belt (at least I think it's the alternator belt). Ever since I had my mechanic do my timing belt and water pump almost two years ago, I've had an intermittent problem where a belt will squeal for about 10 seconds when I start up the vehicle, but only if its been fully warmed up and then sat for a few hours. For example, if I run an errand at lunch, the belt will probably squeal when I start it back up when I go home for the day (4 or so hours later). It seems to happen more often when the sun is hitting the hood. The squealing has now gotten to a point where sometimes it happens when the engine is cold and I've got it in gear. For example this morning it was snowing out, I drive off from my driveway with no noise, but at one point I put it in reverse, and the squealing came back. I also had four wheel drive on at the time.

Again, I assume this is the alternator belt, but I can't say for sure. I asked the mechanic about it a while ago and he said he couldn't really get the pulley on that belt any tighter, so I'm not sure that's the solution. The only reason it gets to me is because it makes my 4Runner sound like a beater and I'm afraid I may be wearing the belt out, or maybe I have an alternator problem?

I'd appreciate your thoughts and suggestions!

 

[lhsoulrebel]

I had a mechanic tell me the same thing... Problem was he tightened the pivot bolt all the way, and not the adjusting bolt... I guarantee it just needs tightening... The power steering and alt belt have a pivot bolt and an adjusting bolt.... Their is an order to tightening.... Search on the site for the belt write up... It's not too bad.. A ratchet set, and extensions and you'll get rid of your problem. I believe the write up is in the 3rd gen ref section.

 

[Xinirgi]

Your belt is loose, pretty much the only reason it would squeal. If your mechanic has indeed already maxed out the adjuster, your belt is either old and stretched now, or you have the wrong belt on (too big) which required more adjustment to make tight. Takes about 5 mins to adjust the belts, hopefully you're good at guessing which one needs tightening.

 

[TheDurk]

If the belt is old and worn out, NO AMOUNT of tightening will make it stop squealing, but may well shorten the life of your alt. My factory alt. belt reached this point at 120k. New belt and problem solved.

 

[gamefreakgc]

x3 on a loose belt. They don't last forever. Change the belt, you'll have to adjust the alternator as well so you'll kill two birds with one stone.

 

[I-4x4]

X4 Loose belt. Just did my timing belt, water bump and all of other belts. I didn't get the alternator belt quite tight enough and it did the same thing.

Guessing it does it when it's warm because the belt heats up, expands and gets looser.

 

[animator]

If it can't be adjusted out any further, it sounds like either the wrong belt is on, or the belt needs to be replaced (which should have been done along with the timing belt).

If they're all new belts, then one is in the wrong location. I forget which, but two of the three belts are incredibly close to the same length, and can be easy to mix up...