Click to enlarge pictureHome Mechanic (© SW Productions/Getty Images)

Working under the hood of a car.

In a down economy, it seems that even our cars and trucks are suffering, too. American drivers have cut back on auto repairs and service, according to a new survey, and many are trying to do more of their own maintenance rather than hiring a professional. The results of these driveway repairs are not always pretty. To simply neglect maintenance, however, may end up costing a car owner far more than would a trip to the local mechanic.

"It's great to see more motorists taking on maintenance issues themselves," says Jay Buckley, an ASE master technician (http://www.ase.com/) and technical training manager for Honeywell Consumer Products. "But some consumers are making poor decisions regarding vehicle care, which could be catastrophic for a family struggling to get by."

A survey conducted by Kelton Research for Honeywell, the parent company of auto-parts brands such as Fram, Prestone and Autolite, found that 21 percent of car owners are avoiding service altogether, and 51 percent are performing bare-minimum maintenance on their vehicles, such as changing the oil and oil filter.

Independent and dealership technicians we spoke to confirm the basic results of the study.

"People are changing their oil frequently and hoping that will keep the car happy," says Steve Marsh, ASE master technician and owner of High Country Automotive Repair in Frisco, Colo., an award-winning shop in Rocky Mountain ski country. "It makes them feel good, and there's nothing wrong with changing the oil, but it's not a substitute for following the manufacturer's maintenance schedule, or paying attention to obvious symptoms. Ignoring the noise under your hood until the engine blows up is not a good maintenance plan."

So what could go wrong? Ask Ken Kranz, an ASE master technician with 29 years of service at Sommers Pontiac/Buick/Subaru in Milwaukee.

"Just last week we had a Subaru Tribeca in the shop with a ruined connecting rod that only had been driven 13,000 miles," Kranz says. "Turns out the owner, who bought the car from our dealership, had never changed the oil since taking delivery. He just wasn't paying attention, and now he needs a new engine and it will not be covered by his warranty."

Click to enlarge pictureChecking Battery (© fStop / SuperStock)

Checking a car battery.

Every tech we spoke with has a do-it-yourselfer story.

"I had a customer who spent $450 replacing four oxygen sensors after his check-engine light came on and a code scan at the auto parts store showed a problem with an O2 sensor," says Honeywell's Buckley, who also runs a private repair business in Michigan. "He came to my shop, and our tech confirmed the scan and discovered that the wiring to one O2 sensor had rubbed through. He repaired the wires in five minutes for a total bill of about $50."

Still thinking you'll just extend that next oil change, or blow the dust off your tool box?

"There's very little that you can do with today's cars," says Marsh, who notes that it often takes special tools just to change the spark plugs. "But the good news is that, if you invest in a regular maintenance schedule, any car should give reliable service for at least 10 years, which is probably many years after the car is paid for. Maintenance is cheaper than car payments."

Marsh says the owner's manual (Have you seen it in the glove box?) should be your guide.

"Find the maintenance schedule and follow it," Marsh advises. "If it shows you how to do something in the manual, like change a taillight bulb or the air filter, then you can probably do it yourself. Develop a good relationship with a trained technician and let him or her do the rest."

Ready to get involved and maybe save a few dollars in the process? Our experts suggest this list of "do it" and "don't even think about doing it" maintenance tasks for the average car owner. Check online for more help. Fram (http://www.fram.com/) offers how-to videos you can download to an iPod and take right to the driveway.

Click to enlarge pictureWoman Checking Tire (© Getty Images)

Under-inflated tires add rolling resistance, so the engine has to work harder to move the car and consumer more fuel. We strongly recommend that you check that your tires are at the recommended pressure at least twice a month.

Do This: Buy a quality gauge (http://www.grainger.com/Grainger/items/2HKY6) and check your tires' air pressure once a month.

Maintain the pressure specified in the owner's manual (it also might be on a sticker often found in the driver's door frame). If you discover a slow leak, you have a chance to get it fixed before the tire is ruined, or before it blows and causes an accident. Properly inflated tires last longer and enhance fuel mileage, saving you money.

Don't Do This: Attempt a driveway brake job.

A botched brake job puts you and other drivers at serious risk. Brake rotor thickness should be checked with a micrometer, and they should be machined or replaced every time the pads are changed. There are a dozen other ways to screw up brakes. It's not worth it.

Click to enlarge pictureChecking Car Fluids (© DreamPictures/Getty Images)

Transmission fluid, for instance, should be checked every two weeks. If it's running low, you will notice the car straining to shift from one gear to the next. This gives it a jerky ride and ruins fuel economy.

Do This: Once a month, open the hood and check these vital fluids: engine oil, brake fluid, power steering fluid, engine coolant, windshield washer fluid, automatic transmission fluid and the hydraulic clutch fluid (on some cars).

Your owner's manual will show you how. The washer fluid will naturally deplete with use, but if any other fluid is suddenly low, it's a warning sign. Seek professional help.

What car repairs do you make yourself to save some cash?