A hissing noise is present in the steering gear.

There is some noise in all power steering systems. One of the most common noises is a hissing sound that is most evident at a standstill when parking. The noise is present in every valve. High velocity fluid passing the valve orifice edges results in the noise. A relationship between this noise and the performance of the steering is not present. Expect the hiss when the steering wheel is at the end of the travel. Expect the hiss when you slowly turn the steering wheel at a standstill. Do not replace the valve unless the hissing is extremely objectionable. A replacement valve may also have a slight noise. A replacement valve may not satisfy the objection. Refer to Power Steering Pump Flow Control Valve Replacement - Off Vehicle .