NEW YORK (MainStreet) — Most drivers do a good job of remembering to change their car's oil, but few keep brake fluid, tires and other key systems in good working order, an AAA survey of mechanics shows.

"Vehicles are so sophisticated today that they'll often keep running even if something's going on, so people forget to keep up with required services," says Greg Brannon of AAA, which polled some 600 club-approved mechanics recently to see how well customers maintain their cars.

Of 10 maintenance items AAA surveyed mechanics about, oil changes were the only one a majority of respondents — 65% — said their clients keep up properly.

Some 44% said customers do a good job with windshield wipers and 42% said clients properly maintain engine air filters, but less than a third said drivers properly maintain any other system that AAA asked about.

Brannon, who serves as AAA's director of auto engineering, attributes the low compliance rates to the fact that modern cars need much less upkeep than vehicles in the old days.

He says many modern cars come with "maintenance-free" batteries or spark plugs that last 100,000 miles, so customers rarely bring autos in for service — making it easy to skip those items that vehicles still require.

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"Years ago, you needed to take a car in every 3,000 miles for a tuneup — but now, there's not even really a service that's known as a tuneup any more," Brannon says. "The downside to that is that whenever you do have a breakdown because you failed to do the maintenance, the cost is much greater."

The expert says the best way to avoid trouble is to read your car's owner's manual carefully to see how often the vehicle needs various services.

Brannon also recommends developing a good relationship with a trusted repair shop, which can keep tabs on your car's maintenance record and contact you when the vehicle needs service. He adds that AAA-approved shops will check over club members' cars for free and look over non-members' vehicles for little or no charge.

Here's a look at services customers rarely keep up with, according to a majority of mechanics polled by AAA:

Brake fluid
Just 12% of technicians reported proper customer maintenance of brake fluid, placing the item dead last on AAA's survey — with an emphasis on the word "dead," because that's what you might be if your car's brakes fail.
Brannon says brake fluid can absorb water over time, making the level look fine but rusting out the system or otherwise causing your brakes to not work. Unfortunately, not all manufacturers specify how often to change this fluid, so AAA recommends every two years unless your owner's manual says otherwise.

Only 18% of survey respondents said their customers properly maintain car batteries. While it's true many automakers bill batteries as "maintenance free" — meaning you no longer have to add water — Brannon says drivers should still periodically have mechanics remove any corrosion that builds up on the terminals.

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Transmission fluid
Brannon says good transmission fluid will last around 75,000 to 100,000 miles and is generally bright red, with any other color indicating that "you might have a major transmission problem." Still, just 19% of mechanics polled said their customers maintain this fluid properly.

Only 22% of shops said their customers keep tires in good shape. AAA recommends checking tires using the "quarter test," in which you stick an upside-down U.S. quarter between your tires' treadwalls. If you can see the top of George Washington's head, your tire has less than one-eighth of an inch of tread left and it's time for a replacement.

Engine coolant
Just 23% of mechanics said their clients maintain coolant properly, partly because cars rarely need coolant flushes these days. Although automobiles once needed coolant swapped out every year or so, modern vehicles can often go 75,000 miles or more without a change.

Accessory belts
These belts typically run a car's air conditioner and alternator, but just 26% of survey respondents reported proper upkeep of them by customers.

Timing belt
Only 31% of mechanics said their customers correctly maintain timing belts, even though a snapped one will leave your car stranded where the breakdown occurs — and might even destroy the vehicle's engine.

— By Jerry Kronenberg for MainStreet