Dear Doctor: I have a 1999 Toyota Camry with the four-cylinder engine that has given me a rotten egg smell since 2005. Toyota said it is not the catalytic converter and refused to change it. I was told to change gasoline, tried all different gas and still have the problem. The car otherwise is in good running condition. Do you have any suggestions? -- Dan
Dear Dan: The problem is not the catalytic converter. The rotten egg smell out the exhaust is the catalytic converter working doing its job. If the catalytic converter was at fault, then the rear oxygen sensor would set the "check engine" light. The smell is usually caused from gasoline brand. It can take five fill ups to clean out the smell from a catalytic converter. I would run the gas tank down to just under 1/4, switch the brand and gasoline grade to a higher octane. The higher the octane the hotter and cleaner the gas burns. The premium grade will not harm the engine or drive the computer crazy.
Dear Doctor: I recently had my transmission re-done on my 2002 Chevy Impala. It still ran a little tight with the shifting of gears. I was told to go to the dealer to have the new software programmed into the new parts of the transmission and this would cost me about $75. Is this common practice? -- Bob
Dear Bob: Reprogramming (reflashing) both engine and transmission computer systems is a common practice after certain parts are replaced, or when the manufacturer has a drivability or emission issue. Even some ignition keys and power window replacement switches need to be reprogrammed when replaced.
Dear Doctor: I own a 2004 Chevrolet Cavalier. Can I buy the brake pads at an auto parts store or should I buy the original brand brake pads from the dealer? If I buy from an auto parts store, what are some of the better brand names? -- Jane
Dear Jane: I use only name brand pads and shoes to limit brake squeal. If you go to an auto parts store, then ask the counter person which brand they have the best service with. Some brands may still offer a lifetime free replacement. Make sure the brake rotors are in good condition on your Cavalier. Lubricate the caliper slides and clean off any rust from the contact surfaces. Also apply anti-squeal compound to the non-friction side of the brake pads. On vehicles with rear drum brakes, always check the brake shoe adjustment. The rear brakes must be properly adjusted to ensure proper braking.
Dear Doctor: I work in a fleet repair shop and we have four types of colors on the different makes of antifreeze. General Motors: orange; Motorcraft: gold; Extended Service Ethylene Glycol: red; Ethylene Glycol: green. Is there really a difference between the different types of antifreeze? -- Ken
Dear Ken: Each car manufacturer has its own special chemical antifreeze make up, including dye color. You can use a name brand universally in most cases. We stock a case of each brand for top-off on new vehicles. On a complete flush we use a name brand universal antifreeze. Always check the label on the antifreeze to make sure it is compatible with the vehicle. The replacement time varies among vehicle manufacturers.
Dear Doctor: I bought a new Buick Rendezvous in 2002 that had a noise in the steering. It almost sounds like a groaning noise whenever the steering wheel is turned sharply. While under warranty the dealer insisted there was nothing wrong with it. After the warranty expired, the dealer said it was the rack-and-pinion steering and the charge to fix it would be $900. Another mechanic told me that he doubted it was the rack-and-pinion steering and advised I do nothing. Other than the noise, I have experienced no other problems with the steering. I also have a friend who owns a 2003 Buick Rendezvous, which makes the same noise. What should I do? -- Ruthi
Dear Ruthi: Some power steering pump groan is normal when the steering wheel is turned all the way in either direction. The noise emits from the high pressure in the power steering pump bypass and vane system.
Junior Damato is an ASE-certified Master Technician. E-mail questions to firstname.lastname@example.org. Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347. Listen to Junior online at 1460wxbr.com Saturdays from 7 a.m. to 10 a.m. EDT.
Copyright, Motor Matters, 2009