Drivers may see red over high prices at the gasoline pump. Ignoring red on a car's dashboard — when red warning lights illuminate — could wreck the engine, lead to a crash or simply lower the car's gas mileage.
When a red light comes on, AAA recommends getting to a safe place as soon as possible and calling for a tow to a repair shop.
"That's considered a serious warning and you should stop driving or risk damage to your car," Meredith Mitts of AAA Minnesota-Iowa, said. "Even if your vehicle does not stop driving right away, it could cause danger to you as the driver and anyone on the roadways around you when it decides to stop working."
Dan Burns with Lloyd's Automotive Service in St. Paul sees worst-case scenarios that result from ignoring warning lights.
"The oil pressure light came on, they ignored it and continued to drive the vehicle and ruined the engine," Burns said. "We don't see that every week or every month but certainly probably every year we see that."
Gary DeRusha, who with his wife, Jane, manages Bobby & Steve's Auto World in Eden Prairie, had a customer recently who ignored the coolant level warning light and, as a result, needed a new engine. The customer kept driving while coolant leaked from the water pump, overheating the car until it got so hot it cracked the cylinder head.
"It's still cheaper for him to put a new engine in than it is to go buy a new car, but you have to have some common sense," DeRusha said. "Those lights are designed to help you and protect you from causing damage like that."
Don't ignore any dashboard lights unless you know what they mean, Burns said. Details on each light are in the owner's manual.
Know your lights
These are the warning lights that drivers absolutely cannot ignore:
Low oil pressure: "If your engine has low oil pressure, then your engine is going to fail," said Burns, who has four decades of auto service experience. "You would need to deal with that immediately."
Engine overheating: You have a little longer than with low oil pressure but not much. "Maybe you could exit the freeway before you pull over, stop and shut the engine off," Burns said.
Check engine: This one is tricky because dozens of issues could cause the check engine light to activate, Burns said. Some need immediate attention, others can wait.
"If you ignore your check-engine light and it's not an emissions problem or something that doesn't affect the running of the car, the car will still run fine," Burns said.
"The trouble is that because now the light is on if a more significant problem arises you won't know that," he said. "It's a little risky to drive with the check-engine light on. You should get the repair made so that the check-engine light is off. Then, if a more significant problem occurs, you'll know that."
If the check-engine light comes on soon after filling up the car, it could mean that the gas cap isn't on correctly and is letting too much air into the tank, Mitts said. Stop, undo the gas cap, retighten it and drive another mile or two to see whether the check-engine light goes off.
"If you're worried about gas prices, many of the problems that will turn on your check-engine light have to do with fuel economy and fuel efficiency," Burns said.
Other warning signs
Brake system: On many cars, the parking-brake light and brake-pressure light are the same light, Burns said. If the light is on but the parking brake isn't, the problem may be with the brake components or hydraulic system. Experts recommend stopping as soon as possible to do so safely. Then, have the car towed for repairs.
Low tire pressure: The light comes on when pressure is low in one or more tires. Find a safe place to check the tires and fill them with air. Drivers should check tire pressure themselves and not trust that the car is keeping track of it correctly.
This warning also could mean that tires are overinflated. A label on the driver's door area lists the proper tire pressure; some cars have different pressures for front and rear tires.
Battery: When this light is on, the alternator is not recharging the battery. A driver can let it go for a little while, but eventually the battery voltage will get low enough that the engine stalls.
Coolant level: Short-term driving should be OK if the driver adds coolant soon, Burns said. If the engine overheats, the driver should pull over in a safe place to let the engine cool before driving farther.
Airbag: This light means the airbag system failed a self-test when the car started or while driving. This disables the airbag system to keep it from falsely deploying. But they also won't deploy in a crash. "It's safe to drive but not safe to drive," Burns said. "I mean, you're driving without airbags, which we know save lives."
Seat belt: When seat belts are latched, the system will tighten them at the same time it deploys the airbags in the event of a crash, Burns said. If seat belts aren't latched, airbags won't deploy in a crash.
Keeping the lights off
Routine and preventive maintenance can help keep warning lights from coming on. "The cheapest insurance you have on a car is to make sure you've got good fresh oil in it and it's full at all times," said DeRusha.
DeRusha, who has worked in auto service for 32 years, also recommended checking coolant, power steering and brake fluids and filters, belts and hoses. Antifreeze, counterintuitively, will help prevent some breakdowns, especially in the heat.
When a check engine or other warning light does come on, some auto repair shops, parts stores and dealers will do a free reading of the car's on-board diagnostic system to identify the problem. Drivers can check AAA's website for car care centers that the organization has vetted at aaa.com/autorepair.