Auto Doctor: Minivan sliding doors require regular maintenance

Dear Doctor: I have a 2013 Chevrolet Malibu that leaves a white stain on my driveway. The dealer says it's condensation from my air conditioner. Can you advise? -- Bobby

Dear Bobby: The white color should disappear in a couple of months. All vehicles with air conditioning have a heater-a/c box drain. The condensation draining from the box, especially on a new vehicle, can leave a white color from the water coming off the evaporator. If there was a coolant leak, then the coolant level would need to be refilled.

Dear Doctor: I have a 2000 Honda Odyssey with 160,000 miles in perfect running order however, the sliding doors are not always operating properly. What could be the problem? -- Elisabeth

Dear Elisabeth: We service and repair a lot of minivan sliding doors -- both power-operated and non-power. These doors need to be serviced at every oil change. The doors require cleaning and lubing at the lower track (which always collect debris and will rust up if not treated), as well as the upper slide rail and rollers and all latches. In some cases when the owner does not want to spend the money for a failed electric slide motor we disconnect the motor and cable.

Dear Doctor: I have a 2011 Acura TSX four-cylinder automatic with 15,000 miles. I never get more than 22 mpg in local driving and 24 on the highway. The EPA fuel economy estimates for city are 18-26 mpg and 25-37 mpg for highway. I'm a conservative 77-year-old driver. Can you explain what can possibly be causing this? -- Basil

Dear Basil: Gas mileage and the way the EPA conducts its fuel economy estimates have changed for 2013 and are much more accurate. Many factors affect gas mileage, including oxygen sensor response, tire size and pressure, driving habits, engine operating temperature, mass air flow meter for cleanliness, just to mention a few. Another thought is the way the gas mileage is being checked and the gas pump filling the tank -- how much does it actually fill the tank before clicking off. Even a different gas brand will make a difference.

Dear Doctor: I am the proud owner of a 2005 Ford Mustang GT with 31,000 miles. Each year from about Nov. 1 to March 31, I keep it covered, in a garage, on jacks, with the tires off the ground and the battery disconnected. The Mustang has the original battery and tires. I've read and been told that given the age of the car I should replace the battery and tires. But the tires still have a lot of tread on them and the battery has shown no sign of weakness. What are your thoughts on the matter? -- Marty

Dear Marty: The rule is 3 to 5 years on battery replacement and 8 years on tires when a vehicle is used 6 months a year. As long as the tires are not dry-rotted, cracked or worn, you can keep them on. For the battery, there are two ways to check it. The newest way is a continuity test and the old is an actual load test. The continuity tests are the most common and take less than 15 seconds and in my opinion are 85 percent accurate. When it comes to battery replacement, the largest cold cranking power lead acid battery is still the best choice. You should also buy a battery maintainer and charge the battery when you disconnect it and again on a monthly basis.

Dear Doctor: I have a 1995 Toyota 4Runner with power door locks. The rear hatch door will not unlock and the back window does not work. All of the other doors work fine. How do I get the door and window to open? -- Allan

Dear Allan: The technician will need to remove the inside panel and check for power and ground at the latch, making sure the actual latch manual release is not rusted and frozen. It could be a poor ground connection or broken wire. A few simple tests need to be performed.  -- Junior Damato, Motor Matters

Junior Damato is an ASE-certified Master Technician. Email questions to info@motormatters.biz. Mail questions to: Motor Matters, PO Box 3305, Wilmington, DE 19804