Thanks for feedback. Sorry to hear it isn't solved. Am cheering for you! All the best!

 

My protege sqeels whe nothing is on except the motor. it only does this when it is cold or wet if sitting still. However, when moving, it squeels if being driven at 20 miles an hour or less/when stopping/taking off (but only if the heat is on). i have become accustomed to turning the heat off before breaking and back on when up to speed. this is a real pain. I have had all belts replaced and the alternator replaced and there was a slight substantial decrease in the noise for a few weeks, but now it is back to being annoyingly loud. Unfortunately there are no mazda dealers in town. I have had a chevy machanic and a general mechanic work on it with no luck. I have not had any other problems with this car. I have read everyone's post on this subject. Thanks for all the suggestions. It seems to be hit or miss. i wish i could afford to just fix every suggested solution.

 

Holley:
You need to use quality belts: Gates
you need them properly adjusted for tension and alignment.
You need the pulleys slightly roughed up with sand paper to provide some friction.
You need to make sure the bearings in all accessories are good.

 

I did everything you did also, except pay a mechanic.Whats funny is ours would act up then I would adjust belts and it would quiet down then come back.It is very hard to tell where the sound is coming from.My last thought of what it might be is the bearing in the air conditioning compressor pulley.This bearing/pulley is turning all the time even though you may not be using the air.Not sure if you realize when you have defrost on the air cond. compressor kicks on also.I think there are two positions on the heat dial that the air cond. comp. is on.Since you said it stops when heat is turned off it goes away or quiets down try turning heat to different positions and see if it changes the sound.This will be my next move if it comes back I think.

 

Consider a bypass belt that eliminates the compressor as a source. If the squeal goes away you know the source of the trouble is the compressor clutch bearing.

 

thought of doing that if needed.