A mechanic on TikTok has explained why you shouldn’t immediately turn your vehicle’s heater on full blast when you start it.

Matt Von, a mechanic on the platform, shared that even as cold temperatures sweep across the country, cranking your heater immediately after starting your car is, “Something people do all the time that they shouldn’t be doing.”

Von’s video went viral with more than 267,000 views within six days.

Here’s why you shouldn’t do it.

Be Patient

Understandably, as temperatures dip below zero, people will want to have a warm auto as soon as possible.

“Right as they get in the car and start it, they put their heater on full blast to warm up fast,” Von said.

That approach, however, is counterproductive, according to Von.

“The way your heater works is, your engine has to be warm before your heater actually works,” he said.

“So you should wait till your car warms up for a little bit and then turn your heater on, it’ll warm up way faster.”

Users React

Some TikTok commentators agreed, but others have no intention of changing their habits.

“That means I have to walk outside twice before I leave. No thank you,” user @sir_iggius wrote.

“Hey it’s 9 degrees out in Ohio today, Just let me do my psychological thing,” user @miles_deep419 added.

“I will continue blasting my heater right when I turn my car on, I’m too impatient,” user @siennavg16 posted.

“Most cars have control valves that redirect coolant to stay in the engine until it’s warm enough,” user @handbrakebard pointed out.

“Priority #1 is the engine, #2 is your comfort.”

Tips for Driving in Extreme Cold

Driving in extreme cold and wintery conditions can be dangerous. Here are some things you can do to prepare.

Be Prepared

Make sure to check the battery, tires, antifreeze levels and windshield wipers before you leave. Winter tires are a great option before winter begins. Carrying a kit with blankets, water, snacks, jumper cables, an ice scraper and a shovel can help you out of a difficult situation.

In Case of a Breakdown

If you find yourself stranded, stay inside the car for warmth and call for help. Turn on your hazard lights to make your car as visible as possible, and make sure the exhaust pipe is clear of snow to prevent carbon monoxide buildup.

While Driving

Slow down to maintain control when the roads get bad, and make sure to leave plenty of distance between your car and the vehicle in front of you. Accelerate, steer and brake gently.

Most importantly: Remember that defensive driving can be life-saving. Be careful and prioritize safety above all else.