Do I Need To Warm Up My Car in The Winter?

One of the biggest misconceptions about car maintenance and repair comes up time and time again every winter. I'm of course talking about warming up you car (car's engine) during the winter?

Turns out that even in the worst weather conditions assuming you car was made after 1992, you should only need to warm up your car for 2 minutes max. During the average snowstorm / blizzard ; starting and soon after driving your car will warm up you engine more efficiently than any amount of idling.

Of course all myths have a kernel of truth to them. The confusion behind car idling dates back to the days when all cars utilized these little mechanical devices called carburetors. Carburetors are devices that blend air and fuel for an internal combustion engine.

The issue with carburetors is that they operate very poorly in cold weather. Basically, without first warming up, carburetors cannot get the right mix of air and fuel into the engine. Eventually, this might cause the car to stall out.

However, starting in the 80's and continuing into today, car manufacturers used electronic fuel injection in place of carburetors. Electronic fuel injection uses a series of sensors to mix the correct quantities of and and fuel before injecting the mixture into the engine. Unlike carburetors, fuel injectors adjust themselves to different temperature conditions.

Despite the above mentioned truths, many people still choose to to idle their car for 10 even 20 minutes before finally driving off. And usually this wouldn't be a problem; except for the fact that our knowledge of greenhouse gases and gas mileage tells us it is.

Experiments on car idling, done by the United States Department of Energy and National Resources Canada, have found that on average idling a car for 5 minutes increased fuel consumption by 7 to 14 percent. Idling for 10 minutes increased total fuel consumption by 12 to 19 percent. Moreover, a 2009 study found that car idling of all kinds (including cold weather idling) increased total greenhouse gas emissions by 1.6% to 2% each year.

Now in the beginning of this article I mentioned that idling your car for a minute or two might actually be a good thing. Do I hate the environment?......No. Do I want to worsen your gas mileage?......No. But I do want you to understand the importance of oil and lubrication.

For many key ("high friction") components in your car, oil needs to constantly circulate among them to yield safe and optimal performance. The engine for example, relies on an oil pump to circulate engine oil (under pressure) to the rotating bearings, the sliding pistons, and the camshaft. However, when you first stat your car, it takes a few seconds for the oil pump to circulate oil to all the essential areas. Moreover, when the weather is cold, oil is a lot more viscous and therefore takes a longer time to reach all these key ("high friciton") places. So to prevent minor wear and tear from friction inside your car, it can't hurt to let your car idle for a minute or two. See the diagram (figure 1) below to see how the oil circulation system in you engine generally operates.

On a personal note, if the weather is cold enough I usually don't care how slowly the oil in in my engine is moving as long as its warm and toasty when I get in the vehicle. I'm sure many of you feel the same. But still, every now and then it is good to know the inner-workings of your vehicle.

See the very-helpful youtube video below from Integrity Auto Repair about this subject. They give some very helpful tips and considerations including the use of remote starters and block heaters. Also check the references section for other winter related articles.