Just a note, you're actually best not to let your car idle to warm up. The best way is to start the car, and start driving right away once the idle settles. And just drive slow keeping revs down until the engine reaches operating temperature.

You can speed up this process by keeping your heater off until the engine is warm as well.

Idling your car is bad, idling the car when cold is worse, 2 minutes is hardly a long time, but if you're doing this stricktly to 'save' your engine, then don't bother, you're much better off doing as recommended above

Although you might think it’s easier on your car to let it sit and gently warm up, doing so is a bad idea for a number of reasons. Most importantly, it does indeed waste gas.

The vast majority of cars on the road today use electronic fuel injection. When your car’s engine is cold, the computer tells the fuel injectors to stay open longer, allowing more fuel into the engine to help it run cold. As the engine warms up, the injectors let in less fuel and everything returns to normal, so to speak.

The problem is, letting your car sit and idle is the slowest way to bring it up to operating temperature because it’s generally sitting in your drive at just above idle speed. And this method to warm up also invites other problems. Remember that modern cars are equipped with a multitude of devices to help them run clean, including a catalytic converter (sometimes three of them), a device in the exhaust system that works to burn off unburned hydrocarbons in the exhaust stream. A cold engine emits a far higher percentage of unburned hydrocarbons than a warm engine. Unfortunately, the average catalytic converter can’t process 100 percent of unburned hydrocarbons even in the best of times. Importantly, the catalytic converter needs high exhaust temperatures to work properly. Throw in a cold engine emitting a high percentage of unburned hydrocarbons, repeat several hundred times, and you can end up with what’s called a “plugged” converter. In a nutshell, the converter becomes overwhelmed and literally ceases to function. This won’t happen all at once but over time, the end effect is the same: poor mileage and significantly dirtier exhaust.

The best bet? Even when it’s 10 degrees F outside, start your car, let it run for 30 to 60 seconds to get all the fluids moving, then drive off gently. Your engine will warm up faster, your exhaust system will get up to temperature faster so the catalytic converter can do its thing, and you’ll use less fuel. Which is what you wanted all along anyhow, right?

If it's below zero outside, it would be a good idea to give the engine five minutes or a little less before you drive off into the frozen wilderness!


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In these modern times most of us don’t think once, never mind twice, about warming up our engines. We turn the key and expect our vehicles to be ready to go. But despite technological advancements, are we compromising performance, or even shortening the life of our vehicles?

From the invention of the automobile until the late 1980s, fuel delivery was regulated by a carburetor – which often required a warm-up period to ensure smooth operation. Modern cars start easier in varying climates than their predecessors because they’re fuel-injected.

Let’s take a moment to think about what happens in an electronic fuel-injected engine when the ignition key is turned. The fuel-injection computer calibrates precisely how much fuel is required. When your car engine is cold, the computer directs the fuel injectors to allow more fuel into the engine. As the engine warms, the injectors let in less fuel.

“You get a lot of old wives tales, and even mechanics will argue amongst themselves. There’s not a definite answer; you can find two mechanics with two different answers,” says veteran mechanic Russ Perry.

“It doesn’t hurt to start and let it warm for a minute or two, or to start and drive away. It comes down to your preferences. If I had a brand-new vehicle I was really proud of, I would want to let it warm up for a minute or so, but that’s more of a psychological thing.

“What I tell my customers when they’ve asked me this question over the years: in ordinary summer, spring, or fall weather – get into your car, start the engine, and while putting on your seat belt, getting comfortable, checking your mirrors and turning on your radio, 30-45 seconds have passed, so put it in gear and off you go,” Perry says.

“People argue that at 32 F or 0 C [freezing], the oil is cold, it’s like molasses, so you should let it warm up – but I’ve never seen oil like molasses when doing oil changes out in my shop, down to -10 C.

“If you’re up in northern Alberta, where it’s -20 or -30, a lot of vehicles are plugged in at night so the battery is kept warm via an electric blanket. They also have a probe that sticks into the oil pan or engine block to keep everything warm. So under extreme conditions, without these devices, yes, you’d want to let it warm up a few minutes because the oil is quite thick,” Perry says.

When I contacted Toyota Canada, its representative said it’s not necessary to warm your vehicle, nor will doing so cause any harm. The rep adds that there are pros and cons: the motor and oil will warm, and the coolant will flow – but idling for long is harder on the environment.

If you have a fuel-injected car, it’s not necessary to warm it up in average weather conditions. If you choose to do so, it may not harm your vehicle – but it could hurt your wallet. There are bylaw fines for idling in many municipalities – including the one-minute rule in Toronto.