Power Steering Fluid
The hydraulic fluid used in power steering systems to assist in turning the wheels.
Power steering fluid is a specialized hydraulic fluid used in vehicles with hydraulic power steering systems. Its main function is to transmit pressure from the power steering pump to the steering gear or rack, reducing the physical effort required for the driver to turn the steering wheel.
In addition to transmitting hydraulic force, power steering fluid lubricates the moving parts within the steering pump and steering rack, prevents internal corrosion, and helps dissipate heat generated by the high-pressure system. Depending on the vehicle manufacturer, the fluid may be a specific mineral oil, a synthetic fluid, or automatic transmission fluid (ATF).
As power steering fluid ages, it becomes contaminated with moisture, dirt, and microscopic metal particles from normal pump wear. This contaminated fluid turns dark and lose its lubrication properties, which can damage seals and lead to pump or rack leaks.
Symptoms of low or degraded power steering fluid include a stiff or hard-to-turn steering wheel, a whining or groaning noise when turning the wheel (especially at low speeds), and visible fluid leaks. Regularly checking the reservoir and flushing the system keeps the steering light and responsive.