How can I fix my car’s air conditioner?

Q. I recently started driving a 2013 Ford Fusion as a company leased vehicle. This vehicle is equipped with a “Start-Stop’’ feature that shuts off and restarts the engine when the vehicle comes to a stop. There is a button that is available that can disable this feature. Are there any general guidelines that you know of for using this feature, such as it is fuel efficient in stop/start traffic when the engine stops/starts multiple times? In the past, the thought was that starting an engine used more gasoline and produced more emissions than letting it idle, although I assume technology has improved this over time. Thanks for the assistance.

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A. You are correct, once it did only make sense to shut off an engine if you were idling for extended periods of time. Today any idling wastes gas. I recently drove three difference cars with “idle-stop’’ and depending on the car some are better than others. In my opinion it is more about how annoying you find the restart. One was a Prius hybrid and the re-starting was almost transparent. The Fusion that I drove started quietly and was pretty tolerable. The last was a BMW 330 and as good as a 3 series car is, I found myself shutting off the idle stop in stop and go traffic because of the raucous sound and feel when it re-started.

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Q. What are the symptoms of CV joints wearing out on a 2005 Toyota Camry?

A. There are four C/V (constant velocity) joints on your car, two outer and two inner joints. The typical symptoms of a faulty outer C/V joint are a clicking noise on turns. A worn inner C/V joint can cause a vibration. The joints themselves are covered in a rubber boot. If the boot is torn or leaking grease the joint should be inspected and the boot or joint should be replaced if necessary.

Q. I’m considering a new Honda Accord with the four-cylinder engine. For 2013 Honda replaced the 5-speed automatic transmission with a CVT transmission. What do you think about the effect on fuel economy, the longevity of CVT transmission and the overall driving experience of the CVT over a more conventional transmission?

A. I have driven the new CVT Accord and found it to be one of the best continually variable transmissions in any car that I have driven. The CVT helps improve fuel economy by always being in the “sweet-spot’’ of that combination of power and economy. The driving experience was totally “normal’’—at first I didn’t realize it was a CVT transmission. Regarding longevity of the transmission only time will tell, but considering Honda’s track record I would expect generally trouble free operation.

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Q. The air conditioner in my car blows only warm air. If I put Freon in, it will be cold for about four hours and then go back to blowing hot air. What can I do?

A. There is a leak that needs to be repaired, just adding more refrigerant without finding the cause of the problem is just a waste of money and not particularly good for the environment. You could try adding a same quantity of refrigerant (generally four ounce cans) with a dye built in and see if you can visually find the leak. There are some leak sealing and recharge products-one is A/C Pro. I have had pretty good luck with this product, but with your car it sounds like you have a fairly substantial leak that may require mechanical repair.

Q. I have had a Jeep for many years and loved it. It would go anywhere and I liked the Jeep community (It is like being in a club-we wave at each other). Now I’m married and have two kids and my husband and I are thinking we should have a more practical vehicle. I was thinking a small SUV like a RAV4, what do you think?

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A. The RAV4 is a good vehicle and the most recent design has only made a good vehicle better. But don’t discount a new Jeep, I recently drove a four-door Wrangler and found it to be a vehicle most anyone could easily live with. The ride was comfortable, off-road ability as good as any Jeep and it has comfortable seating for four-five in a pinch. Even with four doors there is still room for plenty of cargo. The latest V-6 engine in my test car was returning 22 mpg on the highway with an overall city/highway average of 18 miles per gallon. My vehicle had the canvas top which was quiet and generally tight, a hard top is available for winter weather, although I’m not sure it is needed.

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