Nobody likes to pay the bill for car repairs, right? And the more expensive the car repair winds up being, the more disgruntled the customer is likely to be. Granted, when your car needs fixing, it should be done. But it might be instructive to learn where in the U.S. it costs the most to fix cars, on average.

CarMD.com, in its second annual Vehicle Health Index, showed that drivers in the Western U.S. paid the most for car repairs in 2011, at an average cost of $360.89. This is 17 percent more than Midwest drivers paid—and Midwest car repairs were also the least expensive, on average ($309.75).

Some of the reasons why car repairs cost more in the Western states aren’t all that hard to comprehend. CarMD.com says that it can be partially attributed to higher amounts of airborne dust. “By putting off replacing air filters in Western states, vehicle owners put their vehicles’ mass air flow sensors at risk,” said the report. “On average, this is a $400 repair.”

Here are the top 5 states for most expensive car repairs:

Wyoming – Why is Wyoming the most expensive state for car repairs? The data here, and the reasons for it, are clear. CarMD attributes Wyoming’s number one ranking to its harsh weather, high altitude, more remote locations with reduced access to parts and service, resulting in vehicle owners putting off smaller repairs. Catalytic converter repairs were the second most common reason the “Check Engine” light came on. This is a very expensive repair, with an average cost of $1,030.63, and can be traced to the tendency to put off small repairs. Overall, the cost of car repairs in the state was $389.18 (including parts and labor).

Utah – Right behind Wyoming, in terms of top car repair costs, is Utah, with an average car repair cost in 2011 of $378.54.

California – The Golden State isn’t far behind Wyoming and Utah, averaging car repair costs last year of $367.86.

Montana – Over in the Big Sky country, costs to repair cars in 2011 averaged $364.29.

Arizona – With an average total car repair cost of $362.65 last year, Arizona rounds out the top 5 states for most expensive car repairs.

    Another interesting finding of the Vehicle Health Index is that the most common repair across the country was “Replace Oxygen (O2) Sensor.” This is a repair that it often ignored because it seems like the vehicle is driving fine, when in reality, a faulty O2 sensor can lead to as much as a 40 percent reduction in fuel economy.

    Back to Wyoming – the most expensive state for car repairs – O2 sensors accounted for 10.10 percent of repairs in 2011, at an average cost of $233.93. Just ignoring the O2 sensor can then lead to more serious parts failures, like the catalytic converter. If a car’s catalytic converter fails, it can lead to complete engine seizure and roadside breakdown. In Wyoming and four other Western states (but also anywhere else in the U.S.), that can be a dangerous situation.

    Want to know where your state ranks for car repair costs? See the full list here.

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