Power steering is important in modern vehicles because it allows smoother driving and easier control. By taking external power and applying it to the process of turning the wheels, power steering allows you to use less effort to drive the vehicle. Power steering, however, doesn't work when there is no fluid or when the fluid is bad. Knowing when to change your power steering fluid is key in maintaining your vehicle.
Why Change the Fluid
Like any liquid that is designed to work hydraulically, the tests of time and strain eventually begin to break it down. Instead of being able to operate consistently in any situation--including in high pressure, in freezing cold, while the engine is idling or at full speed and even in triple-digit temperatures--the fluid eventually breaks down and needs to be changed. The 1 or 2 quarts of fluid, depending on the vehicle, that run through the power steering pump are the lifeblood of the steering system. Changing it from time to time means keeping that steering system fully functioning and the car's steering easy and reliable.
General Rule of Thumb
The best time to decide when to change the power steering fluid is when the engine coolant fluid is changed according to your owner's manual service instructions. If you choose to use the long-life variety, according to AutoMedia, you can change the power steering fluid every 100,000 miles or 5 years. Most manufacturers of average power steering fluid suggest a complete change every 40,000 miles, or every 2 years. You should, however, check all the fluids in your car every 2 weeks to make sure levels are appropriate and colour remains constant. For older cars, fluids like oil and coolant should be checked more regularly.
When to Change It Sooner
Check your fluids at regular intervals. This can be accomplished by looking under the hood of your vehicle and finding a large cap that is typically marked with the words "Power Steering" on it. If it is not, consult your owner's manual to find where the power steering reservoir is located. Unscrew the cap by turning it counterclockwise, and there will be a small dipstick attached to the underside. Clean the dipstick with a clean cloth, making sure not to get any debris inside the reservoir, and gently place the cap back down and lift again. The stick will indicate if there is a need to add fluid.
Check the colour of your power steering fluid at this time. If you find your power steering fluid looking darker than normal, it is time to change it. As the fluid breaks down from wear and heat, it will begin to darken. When the fluid is dark, remove it from the reservoir and dispose of properly. Add new fluid to the reservoir and close the cap, securing it tightly.