Top Ten Car Maintenance Mistakes Mechanics Say Do Most Damage

Jan 23, 2013, 11:00 ET from Corporation

IRVINE, Calif., Jan. 23, 2013 /PRNewswire/ -- 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 can do the most damage to your vehicles? Corporation 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.

  1. Putting off recommended / scheduled maintenance 
  2. Ignoring the "check engine" light
  3. Not changing the oil, or not having it changed on time
  4. Not checking tire pressure
  5. Neglecting coolant, brake, transmission and other fluid services
  6. Continuing to drive when the vehicle is overheating
  7. Not changing fuel and air filters
  8. Having unqualified shops service your vehicle
  9. Using inferior or incorrect parts for your vehicle
  10. Trying to service difficult repairs on 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, Corporation. “As a result, we set out to capture a consensus among our Master Tech committee regarding the top 10 most damaging mistakes they have seen drivers make. We believe this information will help consumers save money in the long run 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. In some newer model vehicles, the recommended service interval may be as long as 12 months, and other vehicles are now programmed to track oil life versus mileage.

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 (<$20 repair) can result in an O2 sensor failure (<$250 repair), which can in turn result in substantial gas mileage reduction, cause the vehicle to misfire and eventually result in the need for an expensive catalytic converter replacement (>$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 – 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.

This top 10 list is based on a survey of factory-trained, Master automotive technicians conducted by CarMD between Aug. 3, 2012 and Aug. 23, 2012. They are the opinions of the mechanics surveyed and meant to serve as reminders to everyday drivers regarding how they can help minimize damage to their vehicles.

About Corp.

The mission of Irvine, Calif.-based Corporation is to empower consumers and the vehicle market by providing the tools and information needed to make better-educated decisions about their vehicles' health and maintenance. An ISO 9001:2008-certified company, CarMD's premiere product is the CarMD® Vehicle Health System™. The company has built the largest, most up-to-date database of diagnostic trouble codes, expert repairs and related costs, which it uses to compile its annual CarMD® Vehicle Health Index™ and to provide its customers with personalized vehicle diagnostic reports featuring the cost of parts and labor for their specific vehicle and situation.  CarMD's team of Master Techs oversees the quality assurance of this database, which currently has more than 3 million verified repairs. For more information about the company, its product and information, visit

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SOURCE Corporation