Breaking Fan Belts

My Sister has a 2003 Mazda Protege that has now been through 4 fan belts! They actually break, starts by squealing then poof, broken belt. They tried replacing the alternator (suspected bad bearings) but still breaking belts. Any ideas?

I’d check the other rotating components. I’ve never had one break, even with a seized AC compressor. Just smoke and squeal. I’d check the AC compressor for your most likely suspect. Anything else would squeal from the moment you started the engine. There’s always the possibility that you’ve got some unicorn that could produce some intermittent condition, but the compressor is the only one assured to present one.

Hmm, nice thought, but given she doesn’t believe in unicorns, I may not get far on that line. As for the AC, she doesn’t have AC so it too is in the unicorn category of non-existence. Apparently it does some squealing when the car starts…??

Check all pulleys for proper alignment.

As noted belts don’t normally break. They usually burn in two when something is keeping them from moving. Does this engine jerk and spin backward when it is started or shut off?

She does not have a big audio amp on her stereo that is putting a huge load on the alternator does she?

Otherwise, if you have replaced the alternator, and you have no A/C, that leaves just the water pump and the power steering pump and perhaps idler pully as suspects. I presume that the guy who is replacing the belts and the alternator is spinning them and they spin OK when the car is shut off.