A whistling noise indicates a vacuum leak.
It could be low on power steering fluid. That is a common problem. It makes a sharp whining noise when you turn the steering wheel.
If the power steering pump is making a whiny noise on a Pontiac Grand Prix, the way to tell if this noise is from the pump or another source is to turn the steering wheel. If it turns hard, the problem might be with the pump. If the belt quiets down after a drop or two of dish soap is placed on the belt, then it was just the belt causing the noise.
worn crankshaft main bearing is the problem
check the power steering fluid level and belt tension.
Brake booster problem?
A chirping whistling noise!
It could be a power steering belt that is wore or stretched. If no luck with the power steering belt check the pulley.
I would suspect a CV joint is bad.
The rattling and whistling on the 94 Explorer sounds like an exhaust problem. Check the exhaust for any leaks or loose connections.
A bad compressor belt can cause a whistling noise while running the air conditioner. A bad engine can also cause this noise.
whistling noise from engine will be caused by a leaky gasket,sucking air. this is usually the intake manifold gasket