toyota corolla '91 squeeking

[Debbie]

my corolla is making a loud squeeking sound. seems to be coming from around the alternator area; I thought maybe the power steering pump, or belt?? The noise increases as I accelerate then when I take my foot off the gas it usually stops. Also, it is now starting to make a 'clicking' sound while it is squeekiing. Any ideas?

[mdshunk]

It sounds suspicious for bearing failure in either the alternator, water pump, or other driven device. A mechanic might use a mechanic's stethescope or perhaps his hand to narrow down which device it is. Often, when bearings fail in driven units like alternators and water pumps, the unit will be quite hot to the feel if you check it after the car has been driven. That may help you narrow down which one is or is not the troublemaker.

The bearing failure may not be in either device that you suspect. It is more often in auxillary pullies called "idler pullies" or "tension pullies". These often make squeaking, then clicking noises. The next step is they literally fall to pieces, shredding the belt and leaving you stranded on the side of the road. These are fairly easy to diagnose. With the belt removed, the idler pullies are moved about with the hand to check for excessive play or tightness and visable wear.

Pray for a bad idler pully, since this is a relatively inexpensive repair. If the bearings are bad in a driven unit like the alternator, water pump, or air conditioning compressor, the repair is quite costly. In the old days, new bearings would be installed in the unit. In modern times, most mechanics know that replacing just the bearings is a lost cause since the rest of the driven unit is very near or at the end of its service life. The normal repair involves the replacement of the whole alternator or other device.

Any of the above repairs necessarily involve the removal of the belt. It is fairly typical to replace the belt at same time an idler pully or other belt driven unit is replaced if it has any age on it at all.