Car Doctor Questions and Answers – Saratogian


Q. I have a question about the tire pressure indicator light on my 2007 Subaru Outback. After anywhere between 8 and 15 miles of driving, the tire pressure indicator starts flashing and continues to flash until ‘at the end of the trip. The pressure in all the tires is good, and even a short break in my trip with the engine off, the light will stop flashing, only to reappear soon after. No suggestion?

A. There are two types of direct and indirect tire pressure sensors (TPMS). Indirect sensors use the vehicle’s anti-lock braking system and have no physical components on the wheel. Your Subaru uses the direct type which uses a battery powered sensor mounted on the wheel. It is more than likely that one or more of the tire pressure sensors is faulty. These battery-powered sensors have an expected lifespan of 7-10 years. When the battery gets low, it can’t send a signal to the car’s computer, and the light flashes to indicate that the system is malfunctioning. The Subaru TPMS costs around $ 75 each plus installation. There are also aftermarket sensors that are less expensive. TPMS is a safety system, until the system is repaired, check the tire pressure monthly.

Q. My 2013 Honda CR-V has 83,000. The car drives well but has a muffled clicking noise, especially on bumpy roads. Last oil change, I asked the mechanic to check. He said there were plastic clips (forgot what) that were loosening, and he tightened them up. It still makes noise.

A. Rattles are a difficult problem to diagnose, but Honda has a few common rattles.
The heat shield of the catalytic converter (part of the exhaust) may vibrate – this would be a metallic noise coming from under the car. Another bumpy rattle in the car could be part of the heater called the heater core, and Honda’s solution was to simply add foam insulation (a fair amount of work). If this was my car I would check all the steering and suspension parts, at age 8 a strut / shock might weaken or one of the brackets might start to wear out. I would just like to rule out any security concerns. I have found that besides a good test drive, the best style shop lift to check rattles is an elevator workout. On this type of lift, all the weight of the car is on the tires, just like on the road. There are also specialized tools for finding rattles (one is a wiretapping device called a Chassis Ear. Eliminating the easy and obvious doesn’t take a lot of time. After that, finding a rattle can get expensive. may be one of those cases where if it’s not dangerous, let time be your diagnostic tool and wait for the noise to become a little more obvious.

Q. Someone told me to leave the wax on for 12-18 hours before polishing it for the best shine. Is it true? Also what do you think of machine pads for applying and removing wax, I see the pros using them all the time.

A. When waxing a car, apply the wax to a square of about two feet and remove the wax as soon as it becomes cloudy. Then continue by slightly overlapping the areas. Where the confusion is, some people want a richer, deeper shine and, in this case, wait a day before applying a second coat of wax. When it comes to polishing wheels, the safest and easiest to use are dual-action pads. High speed pads work great, but without the proper care you can easily burn the paint. If you invest in a tampon, this has been my experience, the more you spend, the better the results.

Q. I have a new car and the dealer recommends nitrogen in the tires. The cost was around $ 75 and it was included in the funding, but I said no. Now I wonder if I should have put nitrogen in the tires. Is nitrogen better than using ordinary air?

A. Air is 78% nitrogen and I’m cheap and would never pay $ 75 for something you can get for free. There are specialized applications where nitrogen is preferred because it is a dry gas and compressed air can contain moisture. These specialized applications include racing, military and commercial aircraft and even space shuttle tires. So unless you’re running or putting your car into orbit, say no to nitrogen.

Q. An evergreen tree left sticky sap on the hood of my car. And I have a hard time removing it. What should I use or does it need professional details?

A. Start by washing the car with hot soapy water (only use car wash soap) and when dry, use a specialized bug remover, tar and sap. Once clean, wax the car again to make it shine again after using the cleaner. If that doesn’t work, a professional draftsman should be able to remove the sap and restore the finish. The longer the sap cooks in the sun, the more difficult it will be to remove.

Q. I don’t know if you have tested varnishes, waxes and ceramic coatings. Which consumer ceramic coating do you recommend? I’ve used Mothers Ceramic with great results (and it’s pretty easy to apply) but auto parts stores have a whole shelf of products. Preferences?

A. Original ceramic coatings were difficult to apply, expensive and preferable for professionals. They also required a tedious paint fix before they could be applied. Some of the original ceramic products cost $ 250 or more for single use and, when applied professionally, could cost between $ 750 and $ 1,000. Quite expensive, although you had to do it once every four or five years. Today, ceramic spray products are kind of a hybrid, Mothers is a good product at a reasonable price, as are Chemical Guys and Meguiars.

– John Paul, Senior Director, Public Affairs and Road Safety, AAA North East


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