Why would a 1994 Geo Prism belts squeal when the car starts?
When the engine is cold, check for serpentine belt condition and
tension with a flashlight and your hand by pushing on the belt at
about the halfway mark between pulleys. There should be 1/2 inch or
less play in the belt. Also check for cracking along the inside
surface ribs of all belts. There should be 3 total belts if you
have air conditioning. Any cracking along the belt ribs and the
belts should be replaced and properly tensioned. If the belts look
ok so far, have a helper start the vehicle while you watch the
pulleys with a flashlight. Any signs of a pulley that is not
rotating with the engine is a sign of the component attached to the
pulley begining to seize. Whether this is a power-steering pump,
A/C compressor or other pulley driven item, it should be inspected
or possibly replaced by a qualified individual.