Q. I've been looking at many new five-passenger vehicles, specifically the Chevy HHR. One thing that bothers me is that there is no head restraint for the middle passenger in the back row. I can understand the visibility concerns associated with locating a head restraint in that position, but because I have three kids, I'm more concerned about the safety of the person sitting in that seat. Since there are many cars, trucks and SUVs that don't have head restraints in the center position, is there an OEM or aftermarket add-on product that can be installed to provide this protection?
A. Although there may be an aftermarket head restraint, the problem is that the car was not crash-tested with this part installed. Because of the lack of testing, we have no way to know if an aftermarket would be a help or a hazard. This is the case with many aftermarket items, such as seatbelt minders and child passenger safety accessories. If a middle head restraint is mandatory, depending on the age of the child, a high-back booster seat may offer the additional margin of safety you're looking for.
Q. I like the idea of not buying gasoline. Does hydrogen really have promise as an alternative fuel?
A. Hydrogen-powered cars have a bit of the "chicken or egg" problem. Vehicle manufacturers are a bit hesitant to mass produce hydrogen vehicles without a refueling infrastructure in place. Hydrogen manufacturers don't want to build infrastructure without customers to buy the fuel. Although recently, I drove several hydrogen vehicles at the Massachusetts Alternative Vehicles conference. After a short drive in both the hydrogen Ford Focus and a Chevy Equinox, my overall impression was they drove just like any other car. Both vehicles performed well and except for the absence of an engine sound were at least as good as their gasoline counterparts.
Q. I have a 1998 Chevy S-10, and when I'm driving it the engine starts to idle very fast. This will happen until I take my foot off the gas. Once I do this, the idle will start to calm down. Could you tell me what you think the problem is?
A. There a several items that could cause this symptom. It could be as simple as a vacuum leak or a faulty oxygen sensor. At this point, I would want to check the engine with a "smoke" machine to look for vacuum leaks and a scan tool to check for sensor data.
Q. I have a 1992 Honda Accord, and the brake warning light remains on all the time. I have checked the bulbs, and the brakes stop fine, so what could the problem be?
A. The brake warning light will illuminate for a couple of reasons: if the parking brake is on, or the parking brake switch is faulty. The light will also come on if there is a leak in the brake hydraulic system, or if the brake fluid level is low.
Q. I was at an Infiniti dealership and the Service Advisor tried to sell me a can of oil additive with my 30,000 mile service. He said if they put a can in the car with the oil change I would get better gas mileage and it would be turning the oil into syththetic oil. I have been told that this is not true. I asked around and people are telling me this stuff is snake oil. What is snake oil? And how are the dealers able to sell this stuff? Won't it void my warranty? The service writer told me it would not, but I'm skeptical.
A. There is no additive that can turn conventional oil into synthetic oil. Most vehicle manufacturers don't recommend adding any additional products during routine servicing. Some dealers will recommend certain products, but in reality it is more about profit than mechanical longevity. Regarding the term "snake oil," the term became a generic name for many compounds marketed as miraculous remedies. One of my favorites was a product sold in the 1950s called HADACOL. This product contained, among other things, honey, vitamin B12 and 12 percent alcohol. This product claimed to cure everything from arthritis to baldness. Follow the manufacturer's maintenance schedule, and keep the additives to a minimum.
Q. I have a 1998 Buick Century with a 3.1 V-6 engine. Whenever I let the gas tank get down to a quarter of a tank or less, the "service engine soon" light comes on until I fill up. Why does this happen?
A. The first place to start is to check the car for computer fault codes. Once the technician has the fault code, they should be able to properly diagnose and repair the problem.
John Paul is the public affairs manager for AAA Southern New England. He can be reached at firstname.lastname@example.org.