We have a 1992 Mercury Tracer with over 200,000 miles on it. Today, while driving over the Golden Gate Bridge, we heard a loud chirping noise coming from under the hood, that built to a loud squeak. The car handled just fine, but we are concerned because we will be driving it several hundred miles tomorrow. Any suggestions as the origin of this noise?
Check all the drive belts for excessive slack, glazing or cracks first.
A quick belt test is after they start making noises, pull over safely, pop the hood and with the engine idling, spray water on the belts. (Use a spray bottle) If the belts stop squeeling/squeeking, you may have found the problem.
If they look good, remove them and (by hand) rotate the pulleys while applying side pressure and listening for a scratching or squeeking noise.
If you detect noises you may find worn pulley shaft bearings.
The pulley list includes the Alternator, power steering pump, the water pump, the drive belt(s) tensioner pulley(s), and the A/C.
Could be any number of things, did you run into a flock of birds? Does the noise stop when the car stops, does it change with engine speed? Open the hood with the engine running and see if you can figure out where the sound is coming from. It could be your serpentine belt or one of the pulleys. If it is only heard when the car is moving and stops when the brakes are applied it could be the squealers for the brakes telling you that the brakes will need to be replaced. Maybe a wheel bearing. Maybe a terrified chipmunk. Without knowing more about the car and it’s maintenance history and more about the symptoms a lot of time could be wasted guessing what it could be.
So it alarmed you enough to post on this forum but not enough to pick up the hood and look.