Whining noise when I stop and turn off car.

Hi,
I have a 1995 Ford Taurus LX approx. Mileage 113700 I don't know the size of the engine all I know is that it's 3.6 fuel injection. This started happening about a month ago when I start the car and the engine is not hot I don't hear anything but as the coolant level starts to go up and I drive the car this high pitched whining noise occurs when I stop at a red light it happens and when I turn off the car it gets very loud then stops after about 5 or 6 secs. I've recently changed the oil put belt dressing on my belts was told that the belt wasn't the problem took it to the mechanic I bought it from he couldn't really tell what it was he said he never heard it before. From the inside of the car it would be on the right side from outside of the car it would be on the left side but I can pin point where exactly it is. Please help this is so embarassing when I turn the car off.

Thank You