What belt(s) should be replaced?

Might very well be the one driving your air conditioner. Mine was very touchy as I didn't want to over tighten. Kind of a pain getting at the bolt behind) if memory serves me right) the power steering pulley.

Try adjusting the belts before you replace them.

Look also for fluid dripping from the cam cover gasket or thermostat housing or hoses. A tiny amount of oil or coolant will make a belt squeal until it burns off.

Is the a/c compressor engaged when you start the car (a/c or defrost)? If not, you can probably disregard the possibility of it being a compressor problem. Given that it happens when you start the car and goes away shortly I would expect it to be a loose alternator belt. You might try making sure all electrical loads are turned off before you start the car (heater blower, brake lights, interior light...) and see if it's any better (squeals less, or not at all, or not as long).

Good luck, John McClary ('94 Miata) jsgmcclary at cox dot net

I have manual transmission. If I turn off the A/C, does that eliminate the A/C belt as a possible culprit?

Never though of fluids causing a problem. Are most of the belts adjustable without dismantling anything?

I have the A/C turned off, because the A/C coolant is about spent, given the car's age.

Strangely enough, leaving the A/C turned off is usually what causes the refrigerant to become spent.

Yep. It's hard to remember to run the A/C for 5 minutes every week when it's below freezing, but it pays off: my '94 has never needed a recharge. Neither has my 1985 Accord.

I don't think it would be that simple. since that belt drives a couple of things and you only have 2 belts to begin with. Mine would give off a squeal when the AC compressor kicked in, so it was easier to figure out. My F150 serpentine belt on the other hand chirps when it gets damp.

I think maybe you missed the point. What I was trying to say was that I think the problem probably is the alternator belt, not the a/c belt, and there are some things you can do, besides just grabbing and feeling it (which works really well), to try to narrow it down.

John McClary ('94 Miata) jsgmcclary at cox dot net

Its a beautiful day and I'm going to go over the inspection of the belt and especially look around for any fluid leaks, etc. Great tips. Thanks.