Is pre‑heating your car engine in winter a myth? Here's the ultimate guide on when to start driving

Let's examine closely the time a car engine requires to reach an optimal operating temperature, which is around 194 degrees Fahrenheit. Under winter conditions, this could take a couple to several minutes. Diesel engines usually require a longer time to warm up compared to gasoline engines. However, this strongly depends on driving style and the driving conditions. In cities where one often stops at traffic lights, heating the engine might take more time than driving on open roads. Generally, it's estimated that the average time to heat up the engine is approximately 10 minutes.

This doesn't imply we should wait until then before starting our journey- this is a misconception. Drivers should adhere to the rules and avoid sudden accelerations or overly high engine speed. You can accelerate forcefully, but remember it should be moderate, maintaining the engine around the middle speed range. Ideally, for a gasoline engine, it should be between 2000 to 3000 revolutions per minute, and for diesel, between 1800-2500 revolutions per minute.

Let's now consider how much time we deploy to heat the engine before driving off. If the engine has the suitable oil, within seconds of starting it, the oil should spread through the pipelines and start lubricating all moving components. This indicates we can safely start driving. However, starting to drive immediately after starting the engine isn't good for the engine. Particularly for used oil or oil with high viscosity, it needs some time to circulate through the oil channels.

In winter, my procedure is as follows: after shutting the door I start the engine, fasten my seat belt, set the air conditioner to defrost, select the right gear and then start driving. In this manner, I give the engine a few seconds to prepare for the journey.

Is it advisable to heat the engine while stationary? The answer, for various reasons, is "no". Primarily, no modern car engine is designed for such heating. Engines are designed for driving, not idling. Hence, a combustion process involving a rich mixture is highly unfavorable especially without load. This not only emits higher exhaust gases, but also shortens the lifespan of several components, such as:

• Exhaust filter systems like DPF, GPF, and catalytic converters, which suffer damage from water and excess fuel. These are costly devices that are essential for proper engine function. Low-speed operations hasten their wear and tear.
• The entire exhaust system. If water remains in it for too long and the car does not sufficiently heat up to evaporate it, water stays in the exhaust system. Creation of water at low temperatures within the exhaust system is natural, but leads to corrosion.
• Engine oil. The quicker it heats up, the faster water naturally trapped in it evaporates. Water remaining in the oil hastens its aging process and reduces its lubrication capabilities.
• Cylinder walls and rings. Water and excess fuel can deteriorate lubrication, thereby speeding up engine degradation. Unburned fuel also enters the oil.
• Intake system and valves. Unheated engines burning rich mixtures create high levels of soot, accumulating in the intake system and valves.
• Chain drive of the gas distribution system. The chain tightened by an oil tensioner remains loose for longer periods, also damaging the sprockets.
• Alternator. While the engine idles to heat up, we usually turn on the windscreen heating, increasing power consumption at low alternator speeds, thus operating under much higher load than during driving.

Nonetheless, I comprehend that some individuals enjoy entering a warm car, even at the slight risk of decreased engine components' lifespan or a minor fine of 100 PLN (roughly $26). However, bear in mind that the costs (especially fuel) are rather high, and we are also polluting the environment since emissions from a cold engine are particularly toxic.

Is there a compromise then? I believe people who prioritize comfort should maintain the windows' cleanliness and dry car interiors, mainly if they heat the car for that reason. They could also invest in a windshield cover to prevent it from freezing, or a decent scraper, perhaps with a brass tip or a mechanical one - although pricier, it's particularly convenient.

Additionally, instead of idling to heat the engine, they could drive slightly more dynamically, at higher speeds or with a subtly greater load than usual (press the gas pedal a tad harder). Consequently, the engine warms up twice as fast and experiences the same wear and tear as while idling.