Idling your vehicle to warm it up or when pulled over is both wasteful and hard on your vehicle's engine. Read on for more information about idling, provided by Natural Resources Canada and Idle Free BC.
Myth: Engines should be warmed up for long periods before driving.
Fact: Contrary to popular belief, excessive idling is not an effective way to warm up your vehicle, even in cold weather. The best way to warm it up is to drive it. In fact, with today's computer-controlled engines, even on cold winter days no more than a minute of idling is usually enough warm-up time. Even diesel engines in very cold weather require no more than a minute of idling before starting to drive. A block heater is a great way to improve efficiency in cold temperatures. Use an automatic timer to turn the heat on two hours before driving.
Myth: Idling uses less gas than restarting your engine.
Fact: Research by Natural Resources Canada has shown that idling for more than 10 seconds uses more fuel that restarting your engine. This is because oxygen sensors on today's vehicles are electrically heated, which prevents the engine from running too rich upon restarting and the catalytic converter does not cool down enough while the vehicle is shut off to justify idling the vehicle.
Restarting also has minimal impact on your vehicle components such as your battery or starter which are designed to be used thousands of times. Any replacement costs would be minimal, and likely recovered though fuel savings from reduced idling.
Myth: Idling is good for your engine.
Fact: Excessive idling can actually damage your engine's components, including cylinders, spark plugs and the exhaust system. That's because an idling engine is not operating at its peak temperature, which means that fuel combustion is incomplete. This leaves fuel residues that can condense on cylinder walls, where they can contaminate oil and damage engine components. For example, fuel residues tend to deposit on spark plugs. As the amount of engine idling increases, the average plug temperature drops and plug fouling is accelerated. This can increase fuel consumption by four to five per cent. Excessive idling can also allow water to condense in the vehicle's exhaust, which can lead to corrosion and reduce the life of the exhaust system.
Please consult your owner's manual or your vehicle service advisor if you would like a recommendation specific to your vehicle or climatic conditions.
Sources: Idle Free BC and Natural Resources Canada