Maaaaaaan, I started my c4 .1 last week and I heard a loud BANG from behind me. Looked back expecting a monkey with a hammer to be sitting on my rear deck lid clearly visible through the rear window. No such luck. Car drove fine, nothing weird, all continued as expected. I did back into the garage that day which I normally never do. No death puddles or broken serpentine belts. Nada. A few days later I start the car and I hear a horrific and very brief SQUEAL from behind me. In four years I’ve never ever experienced anything like this. Shot in the dark guess is a starter motor dying. Today I had an unusually long crank needed to start the car, also a first. That sentence came out funny...........

 

I have never heard of a starter motor making a “bang” sound. Do you have a scanner? I would start there and make sure you find out what is wrong before driving more as that sound is not normal even if it just happened once.

 

Durametric here at home. I’ll give it a whirl.....sounded mechanical not electrical!

 

This is going back to high school and working on old Firebirds. Was a 1968 old in 1980? : )

Typically it's just a DC wound motor that gears into a solenoid that moves fore and aft to engage the teeth on the outer edge of the flywheel.

A solenoid could make a loud clunk but nothing like an ape with an Estwing.

Squealing while starting does sound like a starter/solenoid not fully engaging issue.