Dear Doctor: I own a 2004 Subaru Outback with 55,000 miles. Last summer the "check engine" light came on. After replacing two oxygen sensors (1 up stream and 1 down stream) and a fuel injection cleaning, the light eventually came back on and has stayed on. My mechanic tells me I need to replace the upper left catalytic converter (3 cats altogether). What should I do? -- Stan
Dear Stan: I have always used factory Subaru converters. The aftermarket converters do not work after six months. You must also check for oil consumption and make sure the engine has had a recent tune-up. When a converter fails the fault code will be p0420 and or p0430. Factors contributing to converters failing at low mileage are short drives and very little highway driving.
Dear Doctor: How do I get scratches out of the front windshield? My husband offered to remove the snow and ice and used to much force with the snow scraper. Can the scratches be buffed out? -- Eileen
Dear Eileen: I see a lot of scratched windshields. Glass companies sell rubbing compound to remove scratches as well as water spots. Some large auto parts stores also sell glass compound cleaner. You can also try regular auto rubbing compound. These work best using a small pad on the end of a power drill. Check with the local auto detail shop, too. They may be able to use their own products to remove scratches.
Dear Doctor: I have to add transmission fluid through the transmission dipstick on my 2002 Acura MDX. I went to so many auto stores to buy a funnel long enough with a thin end so it would fit into the dipstick hole. No one sells it. Can you tell me what I can use? -- Mark
Dear Mark: There is a fill-plug that needs to be removed in order to add transmission fluid. The plug has either a 15 or 17 millimeter head. You will need the correct size socket and 18-inch extension and possibly a 1/2 drive ratchet to loosen the plug, as it can be very tight (do not overtighten the plug when you complete the job). You must use factory Acura fluid only.
Dear Doctor: I purchased a used 2002 Nissan Altima with the 2.5-liter engine and with 57,000 miles. After owning it for two weeks, I noticed almost no engine oil on the dipstick. After topping the oil off, I noticed the same thing two weeks later. Turns out the car is burning oil. Also, this car was bought from a used car dealer. Do I have any legal leg to stand on? -- Ed
Dear Ed: These Nissans do have internal engine oil usage problems. They can range from piston ring problems to worn valve guides. In some cases, the use of top engine cleaner installed by a professional technician can clean the carbon from the rings and help cure the oil consumption. The cost of engine rebuild will range $3,500 to $4,500. I do not recommend buying a used engine because you could run into the same problem. The selling used car dealer does have an obligation to warranty the defective engine or refund you the money.
Dear Doctor: Do you recommend Jeep's Grand Cherokee? -- Jerry
Dear Jerry: This winter I drove the Grand Cherokee Summit 4x4 with the 3.0-liter EcoDiesel engine and the Quada-DriveII electronic limited-slip rear differential. The outside temperature on the cold mornings averaged 0-10 degrees. This diesel engine started right up. In the old days, diesel engines took a long time to warm up. With 420 lb.-ft of torque, the diesel engine delivers plenty of power with a maximum shift point of 3,800 rpm and a sweet power range from 1,800 to 2,500 rpm. During the snow storm I drove out of my unplowed driveway in a foot-plus of snow and into town in another foot-plus of snow -- all without skidding or sliding.