Power-Steering Fluid

Simply put, power-steering fluid is the hydraulic fluid that transmits the power in power steering. Servicing it involves draining or flushing out your car's old power-steering fluid and then adding fresh power steering fluid.

Should I do this service when it's recommended?
In power rack-and-pinion steering, fluid pressurized by the pump pushes on either side of a piston mounted to the rack, helping you turn the wheels.

In power rack-and-pinion steering, fluid pressurized by the pump pushes on either side of a piston mounted to the rack, helping you turn the wheels.

Absolutely. The fluid is the cheapest component of your power-steering system. Changing it can help to prolong the life of other, more expensive power-steering components such as the power-steering pump and the stratospherically expensive power-steering rack.

Why do I have to do this?

Over time, the seals, O-rings and internal power-steering components will wear out. When they break apart, they contaminate the power-steering fluid, which forces the power-steering pump to work harder (having to pump little chunks instead of just fluid) and eventually break down.

What happens if I don't do this?

You'll eventually chew up your power-steering pump. It'll have to be replaced at a cost of several hundred dollars, or you'll have no power steering — and you can't easily drive a car that's equipped with power steering when the power-steering system fails. You also may damage the rack, which will require you to take out a small home-equity loan to replace.

Can I Do This Myself?
It depends on where you rank on the Car Talk do-it-yourself scale:
There are two kinds of screwdrivers?
I've successfully hung pictures around the house.
I've changed my own oil.
I've fixed things on my car that involve removing more than five bolts.
I've built a working nuclear reactor out of wood.
Is there any maintenance required between intervals?

If you hear a whining or moaning noise when you turn the steering wheel, you should have your power-steering system checked. Your power-steering pump may be about to fail.

Also, if you notice a leak of any kind, you should definitely check your power-steering fluid level and make sure you keep it topped up. Running out of fluid will cook the pump, too.

Car Talk Tip: If you do a lot of your own car maintenance, and you feel like servicing the power-steering fluid yourself, you'll still need to dispose of the old fluid properly. To find out how to dispose of hazardous materials where you live, check out the 1-800-CleanUp/Earth's 911 Web site.

Posted on 3/31/05