strong>Dear Doctor: I own a 2010 Mercedes ML350 that I purchased new in February 2010. I was told to bring it in for service in November 2010, which I did. They said I wouldn't have to bring it back for one year. I'm concerned about changing the oil. My mechanic said Mercedes uses synthetic oil and I shouldn't worry. Also, I notice a hesitation when I start the car in the morning. Should I bring it in for service? Terry
strong>Dear Terry: There is no question that today's engine oils and other lubricating fluids are far superior from earlier years. Some manufacturers, such as Mercedes, recommend an annual oil change. We owned a 2007 Mercedes E350, which also required only an annual oil and filter service. Personally, I like to see the oil and filter twice a year. This can be done at any qualified service center. As for the engine not starting on the first turn, this could be any number of problems, including initial low fuel pressure, coolant sensor out-of-range or a computer needing reprogramming. The manufacturer should cover this service issue.
strong>Dear Doctor: I have a 2007 Chevy Tahoe. Often a message displays on the dash "Traction Control Off Service StabiliTrak." When this message is flashing the truck seems to jump and pull slightly. I took it to the dealer twice to read the code. They have no solution. Have you heard of this? Jen
strong>Dear Jen: Before any diagnostics can be started the technician will need more information from you. What are you doing when the lights come on? Most of the time with this complaint the driver is applying the brake and coming to a stop, usually around 10 mph or less. If this is what is happening, then the most common problem is a wheel speed sensor, commonly the front speed sensor that gets contaminated with rust. You can also ask your technician to look on Alldata and Identifix for information.
strong>Dear Doctor: The control for air recirculation on my 2009 Toyota Camry is electric (automatic) and seems to have a mind of its own. I am very sensitive to allergens and pollutants and I don't want the outside air to be sucked into the car and into my face. Do you know if there is any way for me to gain control of this setting, so I can decide when it is on or off? Mike
strong>Dear Mike: The HVAC system needs to be turned on to keep the inside air circulating. The a/c compressor operates on most vehicles in the automatic mode to remove moisture from the interior. Most new vehicles have a carbon-treated cabin filter that helps trap pollen. You should have the filter checked on an annual basis.
strong>Dear Doctor: I have a 2006 BMW 530xi with 56,000 miles. When it's at a complete stop the steering wheel makes a shuttering noise when turning it. The shuddering/shaking on the steering wheel occurs more on an incline. The steering noise occurs in drive or reverse but not at driving speeds only when the car is stopped. Why? Sandy
strong>Dear Sandy: The shuddering or shaking indicates air in the system. I have found o-rings that will leak air only, not fluid. You must use the correct power steering fluid. There are no Technical Service Bulletins on this problem.
strong>Dear Doctor: I bought a 2010 Infiniti G37x. All of a sudden the car's horn has a low "beep" instead of a loud "honk." The dealer found the following: "Found low horn inop due to break in ground circuit. Removed filler panel & grill to access harness. Stripped harness at break and resoldered to correct concern. Reinstalled grille." I'm afraid that resoldering will break and is not the right way to do things. Am I wrong? Dara
strong>Dear Dara: Repairing a broken wire as the dealer did is fine. There would be no reason to replace a wire harness for a break in wire.
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