Every time I start up my car I get a pleasant squeal that varies in duration. Sometimes it lasts half a second, other times it can go on for 10-15 seconds. This squeal also shows up when I have my rear defroster on and I disengage the clutch. It will usually continue on until I tap the accelerator or put the car back in gear.

I figure it has something to do with the alternator (perhaps a bearing?) but my knowledge on this area is rather limited.
Any help would be appreciated!!

 

I have perhaps similar squeal on startup occasionally. I have traced to starter. I think it's failing to disengage when engine catches and gets "over sped" by engine leading to squeal. There are other possibilities; AC compressor bearing, cooling fan motor (horrible squeal), alternator, and power steering.

It may help to have someone else start car and listen carefully at front of car to isolate source of noise (not easy to do).

good luck

 

Might even be the belt getting hard & slippery with age.

 

Usually it's the belt being loose. If it's old replace and adjust tightness, if new just adjust. Adjust = you should be able to finger twist at the longest span between pulleys. If looking at the belt with engine running you see it flop up/down it needs tightening.

 

All belts have been checked, and adjusted. The squeal persists. I never actually thought of the starter. The A/C no longer works in my car, not sure if that can still be an issue if it is not functional. I have had problems with the power steering in the past, but it was just line work.

 

It could also be the harmonic balancer/crankshaft pulley. They can develop a slip between the outer belts ring and the inner body when the rubber vibration dampener between the two sections gets loose. I don't know that it would squeal, but it might. Only way to diagnose is to remove accessory belts and see if noise disappears. If yes, the pulley may be the problem.

good luck

 

Another way to diagnose a slipping front pulley is mark it (white paint or sharpie marker?) across the hub & the outer pulleys. Check the marks over a week of driving to see if they move.