Are power-steering flushes necessary?

For a long time, mechanic Ed Nemphos was skeptical about whether vehicles really need a flush of their power-steering fluid.

With engine, transmission, brake, and radiator flushes already part of most vehicles' general maintenance schedule, he didn't want to oversell his customers. But that all changed when Nemphos saw firsthand what old power-steering fluid is capable of.

"I was a nonbeliever in power-steering flushes because I don't like selling my customers anything they don't need," says Nemphos, owner of Brentwood Automotive in Baltimore. "However, I was given a demonstration . . . and witnessed the sludge and grit in old fluid. The grit is like sand that gets into the rack and pinion seals and destroys them, which explains why we are replacing racks on fairly late-model vehicles that were leaking."

Because a power-steering flush is typically not listed as routine maintenance in a car owner's manual, it's been a debatable issue among some auto mechanics.

However, we put the question - Is a power-steering flush necessary? - to several highly rated mechanics. All agreed that periodically flushing the power-steering fluid is good for your vehicle's health.

Vehicles with a hydraulic power-steering system use power-steering fluid. The fluid essentially works in conjunction with the power-steering pump to make it easier for the driver to turn the steering wheel and, therefore, the vehicle.

Brian Peck, director of operations at Midwest Auto Services in Blue Springs, Mo., says he doesn't believe in so-called lifetime fluids, adding that all eventually break down.

"As components wear, the fluid will become contaminated with metal and rubber particles," he says. "Continuous circulation of this contamination will result in increased wear of the pump and gear."

Hovig Manouchekian, operations manager of Funk Brothers Automotive in Hollywood, Calif., agrees, adding that power-steering flushes should be performed as a preventive maintenance measure, just like any other fluid change.

"We recommend a flush to protect the pump from premature failure because of contamination," Manouchekian says.

There are a few signs the power-steering fluid may need to be replaced.

Frank Renda, owner of Superior Care Auto Center in Brooklyn, N.Y., says dirty fluid or noise coming from the powering steering indicates the fluid may need to be changed. Peck adds that if you hear a moaning or growling-type sound as you turn, it could be an indication that the fluid level is low.

"Power-steering systems are sealed, meaning they should not lose fluid over time," Peck says. "If the system needs to be topped off, the vehicle should be inspected by a technician to determine the source of the leak. Drain and refills should be part of the scheduled maintenance interval."

Experts say they typically charge between $99 and $125 for a standard power-steering flush.

One thing the auto pros don't agree on is how frequently power-steering fluid should be flushed. Manouchekian says the service should be done about every two years, while Peck recommends about every 75,000 to 100,000 miles. Nemphos says he suggests a flush every 30,000 to 60,000 miles.

Depending on your vehicle's age and performance, talk to your mechanic about his or her recommendations for a flush.