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ASK THE AUTO DOCTOR: Hot weather plays havoc on tires, brakes andother motor functions

Junior Damato | Ask the Auto Doc

June 20, 2008

Dear Doctor: We live in the hot climate of Arizona where my girlfriend owns a 2005 Infiniti FX35 with 51,000 miles. One of the rear brake pads went to metal contact, while the other three rear pads were worn evenly to about 1/8 of an inch remaining. The front brake pads are still in good condition. If I apply the brakes hard the front of the car will drop down, I think it feels normal. Why did the rear brakes wear out first and why would one pad wear down to metal?

Dave

Dear Dave: Extreme hot weather, as you are subject to in Arizona, can play havoc on all vehicle systems. The brakes should be checked twice a year or each time the tires are rotated. The rear brakes are much smaller than the front and in some vehicles will sometimes wear down before the front ones under certain driving conditions. The one rear brake pad wearing down to metal contact can be due to a number of things, such as a sticking brake caliper piston, dirty and sticking brake caliper slide pins, and a restricted brake flex hose, just to name a few.

Dear Doctor: I own a Mercury Mountaineer. When I turn the air conditioning on for the first minute or so there is a foul odor that comes out the vents. How do I get rid o the terrible odor?

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Tony

Dear Tony: This foul odor is caused from mold and moisture that collects in the heater box. There are many odor eliminator products available in auto parts stores and at dealerships. The disinfectant will be sprayed into the fresh air inlet side of the ventilation system, usually located at the lower outside base of the windshield. You can open the hood, lift up the wiper blade and put a piece of newspaper under the wiper. (Keep any and all chemical sprayoff the windshield). You will spray the solution in 45-second intervals with the heater on and then again with the a/c on. This treatment will be done a few times for the first week and a couple of times for the next three weeks, or until the odor is gone.

Dear Doctor: I own a 1999 Ford Ranger 4x4 pickup with 112,000 miles. Recently it developed an occasional buck around 33 mph. The second problem is when I put the transmission in four-wheel drive the light indicates 4WD, but the front wheels are not engaged. What is the best way to find the source of these problems?

Francis

Dear Francis: The bucking problem sounds like a secondary ignition breakdown, such as spark plugs, wires or ignition coil. The 4x4 transfer case problem can be a number of things. The first step is to check the computer for trouble codes. If there are no trouble codes then the ignition system will need to be checked with a lab scope. As for the transmission, a trouble flow chart will need to be followed. Information for both problems can be found at Alldata.com under the DIY section.

Dear Doctor: I own a 2003 Subaru Forester with 137,000 miles. In March I had to have both cylinder head gaskets replaced. The dealer covered the cost of the repairs, but ever since the head gasket replacement there has been an oil burning smell. I went back to the dealer and they cleaned the underside of the car. The smell is a lot less now. At the time of the cleaning there were no leaks seen. Is it normal for to have a burning oil odor after all these months?

Debbie

Dear Debbie: There could still be a small amount of oil that is on top of the exhaust system. The way the exhaust system is designed and located any oil leakage will end up on the topside of a hot exhaust. Also, there could be a small oil leak onto the exhaust that is burning off. Take the car somewhere else for another opinion.

Dear Doctor: I need your advice on my next car purchase. I have owned four Buicks over the years and currently I own a 2005 LeSabre. Since the LeSabre is no longer in production, my choice would be a Lacrosse. Would I be making a mistakein buying another Buick that might be discontinued?

John

Dear John: GM vehicles are much improved, so too, are dealership relations with customers. The long warranty is evidence that GM has taken away any worry that an owner could have. Buy the Buick and enjoy years of worry-free driving.

Dear Doctor: What is your opinion on the life expectancy of car tires? I have heard different opinions from many shop owners.

Donna

Dear Donna: It's my opinion that when a tire is five years or older it needs to be replaced, regardless of tread depth. There are many tire brands and tread patterns on the market. The smoother the tread design the quieter the tire. The smoother tread will also generate less heat and improve gas mileage. Always keep the tire at the vehicle manufacturer's recommended air pressure.

Junior Damato is an ASE-certified Master Technician. E-mail questions to info@motormatters.biz U.S. Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347 Listen to Junior online at www.1460wxbr.comSaturdays from 7 a.m. to 10 a.m. eastern time. Copyright, Motor Matters, 2008