Auto Doctor: Change spark plugs before recommended intervals

Like all vehicles, the 2013 Toyota Camry needs Like all vehicles, the 2013 Toyota Camry needs new coolant regularly. Photo Credit: Toyota

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Dear Doctor: I own a 2006 Subaru Forester with only 16,000 miles. When should I get the spark plugs changed? -- Conrad

Dear Conrad: Though it's against factory recommendations, I like to see spark plugs changed before the usual 5-year or 50,000-mile mark. I know that some manufacturers even recommend 100,000-mile spark plug replacement, however, I know that spark plugs can seize in the cylinder head, causing a big exercise and expense to remove.

Dear Doctor: I recently purchased a 2013 Toyota Camry and the service technician informed me that the coolant does not have to be replaced for 100,000 miles. Can that be true, and if so, will the rust inhibitors still be effective for that length of time? Also, I was told there's no power steering fluid and the transmission fluid is permanent. Can you advise? -- Marty

Dear Marty: I own a 2012 Camry with the four-cylinder engine that now has 40,000 miles. I've never heard of fluids that do not need to be changed. The Camry is a great car, and like all vehicles, need to be serviced properly over time.

Dear Doctor: I own a 2003 Chevy TrailBlazer with 117,000 miles. Three weeks ago I started having intermittent problems with the air conditioning. I went on a trip and it worked for 140 miles before the hot air came out. My mechanic checked the Freon, which was fine, checked the low pressure cut-off switch, which was ok, and then told me about a service bulletin from Alldata that described my problem and suggested I have the a/c system reprogrammed. I did, but still have the problem. -- Jim

Dear Jim: First, check for any trouble fault codes in the body control module. See if there are any fault codes and make sure the cooling fan is cooling the a/c condenser. High pressure in the a/c system will shut the compressor down. It would be great if the TrailBlazer could be brought to the mechanic while the a/c was not operating. This will take some diagnostic time too find the problem.

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Dear Doctor: I'd like to get the tire size(s) with a softer ride to replace OEM P215/45R17 tires on a 2010 Hyundai Elantra Touring SE. Can such change be completed without altering the speedometer, suspension/fit? Also, what brands do you suggest? -- John

Dear John: When changing a tire size to make for a smoother, softer ride, the most important items are the rim size and tire clearance. Your current aspect ratio is a 45 series tire and there is very little distance between the alloy rim and the asphalt. We need to increase the distance between the rim and asphalt. To do this increase the aspect ratio, such as a 50, 55, or even a 60 series tire with changing the outside diameter by more than 1/4 inch and making sure the tire fits on the rim. Your factory size P215/45R17 can be changed to P205/55R17, as long as the overall diameter is within 1/4 of an inch. As for brand, talk to a tire expert at the tire shop when making your selection -- and do not buy directional tread pattern tires.

Dear Doctor: I've owned many cars, but the one I really miss is my 2003 Dodge Durango SLT. I have started to look for a one as a second car. There seems to be many available with mileage from 110,000 to 175,000. I traded mine in with 109,000 four years ago. What should I be concerned about with this model now? What costs should I expect with the age of it now? What is the average used car price for a 2003 Durango? I remember a front-end recall when I had mine, plus I replaced the evaporator sensor above the gas tank twice. -- JLB

Dear JLB: Today's average yearly mileage ranges from 20,000 to 40,000 miles. There's a big difference between city and highway miles. It is not unusual to see both cars and trucks with the original engine and transmissions with 300,000 miles on the odometer. There is nothing special in service repairs that come to my attention. I suggest having the vehicle checked before the purchase by an ASE-certified technician. If the technician gives the green light on the vehicle, then start with changing of all fluids and a major tune-up, including the ignition coil if the engine has one, as well as the crankshaft position sensor. The price will vary on the condition and demand of the SUV in your area.

Dear Doctor: Have you tested the 2014 Impala? If so, what can you tell me about it? -- Joe

Dear Joe: I owned a big 1996 Impala SS V-8 rear drive that was a regular Impala up fitted with optional equipment. The 2014 Impala comes in both a 195-horsepower, 2.5-liter four-cylinder and 3.6-liter V-6 with 305 hp. I looked closely at this new Impala and was impressed with the aerodynamics covering the underside. The 2014 Impala now has front-wheel-drive and a powerful V-6 and much better fuel mileage than my 1996 model, not to mention all the electronics.  -- Junior Damato, Motor Matters

Junior Damato is an ASE-certified Master Technician. Email questions to info@motormatters.biz. Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347

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