CarMD.com surveyed ASE certified technicians to find out top ten car maintenance mistakes

When it comes to today's high tech cars and trucks, most drivers understand that following a scheduled maintenance program almost always costs less than paying for expensive repair surprises down the road. But which mistakes, bad decisions and missed maintenance items do the most damage to your vehicles?

CarMD.com Corp. surveyed its team of Automotive Service Excellence (ASE)-certified Master Technicians, which has more than 840 years of combined experience repairing cars, to reveal the following top 10 maintenance mistakes car owners make when caring (or not caring) for their vehicles.

Putting off recommended / scheduled maintenance
Ignoring the "check engine" light
Not changing the oil, or not having it changed on time
Not checking tire pressure
Neglecting coolant, brake, transmission and other fluid services
Continuing to drive when the vehicle is overheating
Not changing fuel and air filters
Having unqualified shops service your vehicle
Using generic aftermarket parts instead of original equipment manufacturer (OEM)-quality parts
Trying to service your own high-tech vehicle

"When consumers fail to properly maintain their vehicles, the resulting repair costs dwarf the money that could have been budgeted to maintain their car," said Art Jacobsen, vice president, CarMD.com Corp. "As a result, CarMD reached out to our ASE-certified Master Tech committee to confirm the top 10 most damaging mistakes drivers make. We believe this information will help consumers save money in the long run and plan better as they care for what is often their second largest purchase."

No. 3 in the top 10, "not changing your oil" was also listed by technicians as by far the single most damaging car maintenance item that their customers neglect that they wish they could change. Dirty oil ruins today's high-tech engines. Camshaft actuators can freeze when restricted by dirty oil, and a faulty camshaft actuator can in turn cause the "check engine" light to illuminate, resulting in complete engine failure if ignored for too long. Simply following the factory-recommended oil change schedule helps vehicle owners avoid this problem, along with potentially hundreds, if not thousands of dollars in extra repair costs.

Ignoring the "check engine" light is another example of how putting off repairs on a small problem can escalate to an expensive repair. According to the CarMD Vehicle Health Index, the most common reason for a "check engine" light is a faulty oxygen (O2) sensor. A dirty air filter ($1,000 repair). That's why it's so important to have your car's air filter replaced as recommended by your service manual, and to address "check engine" warnings as soon as possible.

And while these top techs encourage their customers and all drivers to follow a regular maintenance program, they don't want consumers to get lured into spending extra money on unnecessary items. According to CarMD's Master Techs, the best rule of thumb is "any service other than what is recommended in your owner's manual is unnecessary." They recommend servicing your car according to factory requirements, but suggest avoiding gimmicks like injector flushes and nitrogen in the tires, which are a waste of money. CarMD offers its customers "Staying Healthy" reports online with maintenance schedules for their registered vehicles to help know what services their car needs when. CarMD also offers a free online service – available at www.carmd.com/ScoreCard – where anyone can see the most common problems for their own vehicle, as well as how it scores in terms of reliability against other vehicles on the road.