Myth #1 The engine should be warmed up before driving.

Reality True, the engine must be warmed up, but idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is by driving the vehicle. With today's modern engines, and the advent of electronic engines, you need no more than about 30 seconds of idling before driving away, even on the coldest winter days.

Myth #2 Idling is good for your engine.

Reality Excessive idling can actually damage your engine components, including cylinders, spark plugs, and exhaust systems. An idling engine is not operating at its peak temperature, which means that fuel does not undergo complete combustion. This leaves fuel residue that can condense on cylinder walls, where they can contaminate the oil and damage parts of the engine. For example, fuel residues are often deposited on spark plugs. As you spend more time idling, the average temperature of the spark plug drops. This makes the plug get dirty more quickly, which increases fuel consumption by four to five percent. Excessive idling also lets water condense in the vehicle's exhaust, leading to corrosion and can reduce the life of the exhaust system.

Myth #3 Shutting off and restarting your vehicle is hard on the engine.

Reality Frequently restarting has little impact on engine components like the battery and the starter motor. Component wear caused by restarting the engine is estimated to add $10 per year to the cost of driving, money likely to be saved many times over due to fuel savings.

Myth #4 Shutting off and restarting your vehicle uses more gas than if you leave it running.

Reality The bottom line is that over 10 seconds of idling uses more fuel than restarting the engine. As a rule of thumb, if you are going to stop for 10 seconds or more - except in traffic - turn off the engine. You'll save money, and you won't produce harmful Carbon Dioxide, the leading greenhouse gas.