Should You Let Your Car Warm Up in Cold Weather?

The deplorable driving conditions of the winter are already traumatic enough for your car to make things worse. How? Put the ignition in the early morning to “heat” it before you start. If you are one of those drivers who let their cars warm up to a standstill in cold weather, it is because you have been deceived by a legend that is less harmless than it seems!

This is what the engineer and former driver of dragster Stephen Ciatti tell us. For 26 years, Ciatti has been working on engine combustion and has regularly studied any type of combustion at the Argonne National Laboratory in Illinois. Simply put, he says preheating his car to neutral in the cold isn’t just a waste of gas. You deprive your engine of vital oil components that allow it to work, such as cylinders and pistons.


Under normal conditions, your car’s engine works with a combination of air and vaporized fuel. When this mixture enters a cylinder, a piston compresses it, causing combustion and starting the engine. But when it’s cold, gasoline evaporates less well. Your car does that by adding more fuel to the mix (what Ciatti calls “rolling fat”) and that’s where the problem starts.

“It’s a problem because you bring extra gasoline into the combustion chamber to burn, but some of it may end up on the walls of the cylinder,” says Ciatti. Gasoline is an amazing solvent and if you heat it to a standstill in the cold, for a while it will wash the oil from the walls. Over time, the effects can be “detrimental to the lubrication and service life of vital parts (such as piston gaskets and cylinder enclosures) giving breath to your engine” adds Ciatti. Contrary to what we think, heating his car to a standstill does not extend its life. She’s shortening it.


Fortunately, your vehicle doesn’t run ” fat ” all winter. Once the engine is warm enough, the car will return to normal fuel consumption. You might think that by letting it heat up, you’re preventing yourself from that problem. But be careful: the hot air coming from the radiator and a hot engine are two different things! Actually, the problem is the dead heat.”Heating the engine to neutral does not bring it to a good temperature. In the meantime, the engine’s brain continues to send out enriched gasoline to make sure there is enough steam for real combustion.”

Some will tell you that the steering oil (the fluid that allows power steering) will then be too cold to circulate normally. “Impossible” replied Ciatti. “By taking gentle, controlled driving after starting, you will warm up your oil faster, about 30 seconds to 1 minute, to normal. » The steering belt will most likely grate but preheating a car for 5 minutes will have no effect on the steering oil. No. The steering oil will only work if you request it, by requesting the steering belt.


Your engine needs 5 to 15 minutes to warm up once turned on. To push it from the start with aggressive driving is to put it under unnecessary tension. So gently press the accelerator pedal to start. Also, before reaching the right temperature, the car engine will work with a richer blend, decreasing your average fuel consumption.

According to the U.S. Environmental Protection Agency’s Department of energy, your car will burn 12% less gasoline in cold weather. Driving to the floor is wasting fuel according to MIT mechanical engineer John Heywood. Before adding: “The bigger your engine is, the more fuel it will burn to a standstill »


Some legends die hard. This is true of the idea that you have to heat your car at a standstill in cold weather. The origin of the myth dates back to a time when car engines depended on the carburetor. Until 1980, carburetors allowed the engines to run. From the 1980s onwards, however, it was the turn of the electronic injections, which were distinguished by a sensor which fed the cylinder with the right air-petrol combination to produce combustion.

Sensors that the carburetor-dependent cars lacked. If your gas was too cold, your car could not make a rich blend, preventing starting. It was vital to heat the carburetor before driving. But that time is long gone. Yes, you will be cold for a few minutes, while your radiator warms up and sends you warm air. But you will also save a lot of time and money.

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