Power Steering Fluid Maintenance

Pint-for-pint, the one or two quarts of power steering fluid required by your passenger car are probably some of the least appreciated fluids under the hood. Considering what it does, and how much a motorist depends on it, we're talking about the lifeblood of your steering system. Yet keeping it clean and doing its job doesn't require all that much effort.


The function of this fluid is basic: transmitting hydraulic pressure to make steering easy—but achieving a seamless system operation over a wide variety of conditions is not. The fluid must perform consistently in any situation, from sub-zero to triple-digit temperatures, and both ambient and under-hood temperatures. It also must function when the engine is at idle or full-throttle, and under high pressure, all the while providing adequate lubrication to pump and control valve assemblies, maintaining integrity of rubber components in the system, and promoting noise-free system operation. And your fluid has to do all of these things over an extensive period of time!

Transfer Tool
Of course, these demands take their toll on the fluid and break it down, which can lead to inconsistent performance and expensive component failure. Although vehicle manufacturers haven't generally specified in the past when to actually change the fluid, some are doing this now, or they have designed a fluid that they feel will last "the life of the vehicle." Of course, your opinion on a vehicle's lifespan may differ from that of the manufacturer. That said, we'll share a couple of relatively simple and mess-free methods for maintaining the fluid for a much longer period.


If your vehicle's manufacturer recommends a fluid change interval, definitely follow that. Do-it-yourselfers will need to consult a service manual for the procedure on their particular vehicle. If there is no recommended change interval, however, here's a good rule of thumb to follow: Change it as often as you would your engine coolant. Power steering fluid of the "long-life" variety should be changed every five years or 100,000 miles. For conventional fluid, the interval is every three years or 50,000 miles. Most likely, the fluid will appear normal at this point—either amber (on most vehicles) or pink/red in color. This is good, as no serious problems are indicated.

Filler Cap
As with other vehicle fluids, changing before visible deterioration occurs is ideal. The fluid should be checked at every routine service interval, but if at any time before the interval recommended here, it appears significantly darker than new fluid, it should be changed at that time. Use the following easy procedure for evacuation and filling.