Fan belt squeal and broken belts

Hi all, I'm looking for a bit of help. My fan belt is squealing on my 2003 jimny, it starts before the engine is warmed up, and continues when warm. It starts with the belt chirping, then turns into a continuous squeal, and I have noticed lots of rubber dust on the alternator around the pulley. I did initially just tension the belt and it stopped squeaking, but returned back to how it was after just 5 miles.
I have just got the vehicle, but I know the previous owner, and he recently had a new alternator fitted, then the fan belt snapped shortly after, the mechanic who fitted the alternator then fitted a new belt, then I took ownership of the vehicle.
I'd be grateful if anyone could help me pin point the problem.
Thanks.

I'd replace the belt, take the current one off and clean the pulleys thoroughly. I found the bottom pivot bolt a bit fiddly to access as all my Allen key sockets were a bit short but I found something suitable in my toolbox.

Good luck

Thanks. I am about to buy a new belt, I'll run around the pulleys with a wire brush before fitting.

It's probably the alternator bearings on the way out. This happened to mine just before the alternator seized solid.

OllieNZ wrote: It's probably the alternator bearings on the way out. This happened to mine just before the alternator seized solid.

Could be if it has been driven in muddy water.

Mine did the same and it was the alternator stator breaking apart and seizing the alternator.

Most likely needs a new alternator shortly.

See one of my threads reference this problem if your car has a dual cam engine. I had to replace the crankshaft pulley in the end even though the rubber did not look too delaminated. Also do not overtighten the belt and ensure you have the correct length belt fitted. I find it easier to remove the radiator and fan blades when changing the belts as you do not want to damage the rad core which is easy done. Removing the rad gives you the opportunity to flush out the block and the rad and use a new batch of anti-freeze 50-50 mix is what I use.