Q My '03 Mazda MPV with 125,000 miles has the Check Engine light going on and off the past few weeks. The parts store's scan tool found a code for catalytic converter issues. The manager suggested I try a couple cans of Sea Foam or a product called Cataclean, which I've never heard of. It's about $25 for a 16-ounce can. Do either of those products do anything to revive a tired catalytic converter? Hate to spend foolish money on a long shot. The vehicle runs perfectly and has no unusual sounds or smells.
A No additive can repair a failed catalytic converter, but they can clean deposits from a functioning converter and help restore its efficiency. In a nutshell, the catalytic converter matrix is covered with platinum or palladium that, when heated by the exhaust gases, oxidizes unburned fuel to eliminate raw hydrocarbons from the exhaust. As converters lose efficiency, the percentage of raw fuel in the exhaust increases, which is monitored by the rear oxygen sensor.
The good news is that federally legal aftermarket catalytic converters are available at a significantly lower price than most original equipment converters. A quick online check found replacement "cats" for your Mazda starting at under $100, not including installation.
Try the cleaners first, but if the fault code for a failed converter returns, consider an aftermarket replacement unit.
Q I have a 1999 Chrysler Town & Country with 120,000 miles that is in great shape and a very good road car. A few months ago while on a long trip the cruise control would not work. The control buttons are on the steering wheel. It started off working indifferently. Sometimes I could get it to turn on but not work. Very occasionally it worked fine. Sometimes it partially works after turning the wheel lock to lock. About a month after this started, the air bag warning light would go on for a while and then turn off. The light's "on" period became longer and longer until now it is on most but still not all the time. Could it be bad connections in the steering wheel? Is this repairable without spending a lot of money or should I chalk it up to a 14-year-old car?
A The problem very likely is in the wiring harness in the steering column -- particularly if it's a tilt column -- or instrument cluster harness. Yes, it's probably due to the vehicle's age and mileage, but regardless, the issue needs to be addressed. Why? The air bag warning light. When this light is illuminated, the air bag may not function properly in a crash, and potentially could deploy unintentionally.
Have a shop scan for DTC fault codes for the restraint system as well as the cruise control. This should pinpoint the problem and give you an idea of repair costs. Replacing a harness is far less costly than potential injuries if the air bag fails to properly deploy in a serious crash.
I just had to print Susan's letter; it made my day. "I just read Saturday's column and you left me wondering what your semi-professional, completely biased opinion on extended warranty and service contracts is! I think I remember a column on it sort of recently, but can't remember what your semi-professional, completely biased opinion was! Help! I'm a 78-year-old widow and life was so much easier when my husband had to deal with me asking all these questions. Even if he didn't know the answers, he asked someone who could help. Darn it, wish he was still alive!"
Susan, my semi-professional, completely biased opinion is this: If you intend to keep the vehicle well beyond the carmaker's warranty and drive an average mileage of roughly 10,000-15,000 miles per year, seriously consider purchasing a reputable bumper-to-bumper extended warranty or service contract that fits the term and mileage of your ownership.