Download SYMPTOM The power steering pump whines, buzzes, or hums after driving for 30 minutes in temperatures of 35 to 40 degrees F (2 to 5 degrees C). PROBABLE CAUSE The power steering pump reservoir is defective. CORRECTIVE ACTION Flush the power steering system with clean power steering fluid, then replace the power steering reservoir. DIAGNOSIS 1. Run the engine until it reaches normal operating temperature (the cooling fans cycle twice). 2. Listen for abnormal noises from the power steering pump while the steering wheel is centered and not being turned. • If the pump whines, buzzes, or hums, go to REPAIR PROCEDURE. • If the noise is not coming from the pump, this service bulletin does not apply. Check for other possible causes of the noise. 3. Inspect the power steering reservoir. Is there a white dot on the reservoir cover, with one of its ribs pointing toward the reservoir holder? Yes – This vehicle already has the revised power steering reservoir. Continue with normal troubleshooting procedures. No – Go to REPAIR PROCEDURE. POWER STEERING RESERVOIR COVER 2. Drain the fluid from the power steering system: • Connect a suitable diameter drain hose to the disconnected return hose.