Q I have a 2009 Chevy Cobalt. When I needed four new tires, I mounted the new tires on new aluminum rims rather than on the original steel wheels. Now, the "SVR Tire Monitor" warning light comes on every time I start the car. The original tire pressure monitors are still in the original steel wheels, which I've kept as spares. The aluminum rims did not come with tire pressure monitors -- adding them would have cost another $300. How do I disable the warning light so that it doesn't come on every time I start the car? It's annoying to have to hit the reset button on the steering wheel every time I start the car. There should be an "on/off" switch so the car owner can check the tire pressures when he wants to!

A Here's the simplest answer. If the light really, really bugs you, put a small piece of black electrical tape over the warning light -- problem solved. I know of no way to disable the tire pressure warning system. Why? Because the overwhelming majority of motorists fail to check tire pressures, this system is now mandated on today's vehicles to effectively force car owners to pay attention to tire pressures.

My 1970 Corvette, which I've owned for 40-plus years, features a seat belt warning light on the dash that must be manually turned off with a push of the button every time I start the car. It's never been an issue for me. If you choose to check your tire pressures manually, good job! But recognize the benefit of the warning system to alert drivers to the potential safety hazard of low tire pressure.

Q I've been driving my 2000 Malibu for months on five cylinders. I know it's hard on the car and bad on mileage, but is there a safety issue? I can't afford to get a new cylinder.

A I don't think you can "get" a new cylinder. If a six-cylinder engine is running on five cylinders, that means one cylinder isn't doing its share of the work. In the priority of easiest to fix, the potential causes are: a bad spark plug; a bad coil, coil pack or plug wire; a fouled or failed injector; a stuck, burned or broken valve; or a leaky head gasket. Next on the list are: worn or broken piston rings; a holed or broken piston; or a scored or damaged cylinder wall.

A single cylinder failing to fire doesn't present an issue in terms of driving safety, but, like you said, it's not doing the engine, emissions or your mileage any good. If you haven't had the problem diagnosed yet, I'd suggest having the engine performance analyzed to determine the exact cause. It may be a relatively inexpensive repair.

Q I have an '03 Subaru with 123,000 miles on it. After routine maintenance at the dealership I was told the car needed new head gaskets. The mechanic had detected oil leakage. After hearing the $2,500 quote, I asked the service manager why this was so expensive. He said it was a big job and listed the steps involved, including replacing the timing belt. Since I had the belt replaced at 104,000 miles, I asked why it needed replacing again. He said reinstalling the old belt was not recommended.

A You've raised two issues I'd like to address. First, Subaru suggests a careful inspection of the timing belt before reinstallation. If it has any cracks on its inside or outside surfaces, or is contaminated with fluids, it should be replaced.

Secondly, with the age and mileage of your vehicle, I would hesitate to have the head gaskets replaced until there is a serious driveability or durability problem. If the oil leak is external and visible at the junction of the cylinder heads and block, it won't cause a problem -- only a mess -- unless you allow the engine to run low on oil. If, for example, you don't have to add more than a quart of oil between oil changes every 4,000-5,000 miles, I don't think the leak is serious enough to warrant a major repair.