Power Steering Reservoir
The plastic or metal container that holds the power steering fluid required by the hydraulic power steering pump.
The power steering reservoir is the storage container for power steering fluid in a hydraulic power steering system. It supplies fluid to the power steering pump and receives returning fluid that has circulated through the steering gear or rack and pinion. It is usually mounted in the engine bay for easy access.
Most power steering reservoirs feature integrated fluid level markings (usually labeled "Hot" and "Cold") or a dipstick attached to the cap, allowing drivers and mechanics to check fluid levels easily. Many reservoirs also contain a fine mesh filter screen at the bottom. This filter traps metal shavings and debris generated by normal pump wear, preventing them from recirculating and damaging the steering gear seals.
Over time, the plastic housing of the reservoir can become brittle from engine heat and crack, leading to fluid leaks. Additionally, the internal filter screen can become clogged with sludge, restricting fluid flow to the pump. This restriction starves the pump, causing it to whine loudly, overheat, and eventually fail.
When replacing a failing power steering pump or steering rack, it is highly recommended to replace or thoroughly clean the reservoir, flush the old fluid, and install a new return-line filter to prevent residual metal debris from ruining the new components.