Brand: Driver's airbag is automatically armed

Q: I'm driving a 2015 Chevy Cruze. I use a rotating cushion for ease in getting in and out of my car. When I ride in the passenger seat using the cushion while somebody else drives the car I noticed the passenger airbag light on the console says it is off. Through trial and error I found that the rigid bottom of the cushion prevented the seat from sensing a person on the passenger seat thus preventing the airbag from turning on. Without that cushion it works fine. My question, as dumb as it sounds is: Does the driver's side work the same way since there is no airbag indicator light for the driver seat? Logic would dictate that the airbag for driver is always "on" when the car is in use. How can I be sure?

A: Your analysis of the driver's side airbag function is correct — this airbag is always armed while the vehicle is running. Your confirmation is the fact that if, for whatever reason, the driver's airbag was not capable of deploying, the airbag warning light on the dash would illuminate.

Q: My dealer's service department wants to do a fuel injection service every 15,000 miles. At $140, is it worth it or necessary? Will a can of SeaFoam be just as good?

A: Fuel injection cleaning service can be beneficial if there are symptoms of a fouled fuel injector such as misfires from a specific cylinder or loss of performance and/or idle quality. A fouled injector delivers a poor spray pattern of fuel and may not atomize the fuel properly. Think of a shower head with clogged nozzles due to calcium deposits.

Today's gasolines contain detergents to help keep injectors clean, so I don't believe routine injector cleaning is necessary. With that said, I do add SeaFoam periodically to help keep the entire fuel system clean and moisture-free.

Q: My query is regarding the headlights on my '05 Elantra. They are dull. I bought a cleaning kit at the parts store for $10 They cleaned up some, but I want cleaner! Any advice?

A: Sure. More elbow grease. Restoring the clarity of polycarbonate headlights is akin to polishing metal. The key is to "finish" with one grit before starting with the next finer grit. If you leave scratches that could be removed with the heavier grit, the finer grit won't remove them. Like I said, elbow grease and more elbow grease.

A: Is it a hot oil or hot coolant odor? Hot coolant is the easiest to distinguish because it has a somewhat bittersweet smell. Hot coolant dripping on the exhaust — even a very small amount — would create the odor but leave little or no physical trace.

Perhaps the next step would be to pressure-test the cooling system and check the coolant for the presence of hydrocarbons — a relatively quick loss of pressure after shutting down and/or contamination with exhaust gases could point to a failed head gasket. Adding a special dye to the coolant to check for specific leak evidence with a black light after a week or so of driving could identify an external coolant leak. The same type of leak detection can be used for the oil, as well.