If your car is making a squealing or squeaking sound when you turn the steering wheel, there could be any of several culprits at play.
One common cause is low power-steering fluid. When the fluid that powers and lubricates conventional power-steering systems gets low, it can lead to a squealing noise that may sustain for as long as the steering wheel remains off-center. Checking the fluid and replacing if necessary might be enough to solve the problem. Contamination of the fluid by dirt and debris also could be at the root of the problem. A failing power-steering pump could likewise be the cause. If adding fluid doesn't solve the problem, a technician should be able to identify the cause and recommend a repair.
A suspension or steering component that's lost lubrication also could cause a squeak or squeal when the steering wheel is in motion. Tie-rod ends, seals, ball joints and universal joints all need lubrication, and if they dry out, that could lead to noise. Again, a technician should be able to identify the problem and recommend a repair.
We've also experienced squeaks from the steering wheel housing in new cars rubbing against interior trim — typically in hot weather when materials expand and gaps close up. In these cases, a trip to the dealer or body shop might be in order — hopefully for warranty work.
Finally, tire noise could be the cause of the squeal that you're hearing, especially if it happens only when the vehicle is driven on certain surfaces.
If your vehicle is making a squealing sound when the steering wheel is being turned, start by checking the power-steering fluid level and replacing/adding as necessary — and if that doesn't eliminate the noise, make an appointment with a service technician.