check the fluid in the Power Steering pump
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.
check the power steering fluid level and belt tension.
Brake booster problem?
Your AC unit may be making a whistling noise due to a clogged air filter, a refrigerant leak, or a problem with the fan blades. It is important to have a professional inspect and repair the unit to prevent further damage.
The rumbling noise could be due to issues with the exhaust system, such as a hole in the muffler or exhaust pipe. The whistling noise could indicate a problem with a worn-out or loose belt or a leaking vacuum hose. It is best to have a mechanic inspect your car to diagnose and fix the issue.
It could be a power steering belt that is wore or stretched. If no luck with the power steering belt check the pulley.
A chirping whistling noise!
Your air conditioner may be making a whistling noise due to a blockage in the air filter, a problem with the fan blades, or a leak in the ductwork. It is important to address this issue promptly to prevent further damage to your air conditioning system.
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.