I have an 02 Protege5 that makes a terrible squealing noise when started up in the cold and engaged the clutch. Or when driving and I turn on the heat. I tried popping the hood and feeling the belts right after its squealing and none feel hot. Any ideas?

 

Slippage due to additional current draw. Replace the belt(s,) w/new of course, and a proper torquing, clean the pulley's, That should solve the problem.

 

My 2000 Protoge 1.6 does the same thing. I replaced the alternator belt and tightened it but can't get the noise to go away. The belt doesn't show any signs of slipage wear. Could it be something else? It makes so much noise that I can't tell where it is coming from. Frustrated.

 

most likely, the pulleys are dirty. when a belt starts to slip, it leaves bits of rubber and debris behind. i always recommend going over the pulleys with a wire brush before re-installing the belt.

the other possibility is that the shaft on the water pump is bent.