How Does Hot Weather Affect Your Car?

Extreme heat can play havoc with your vehicle, so it’s a good idea to take some precautions.

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Summers across much of the U.S. have grown hotter over the past several decades, and scientists predict this warming trend will continue, bringing longer and more frequent stretches of extreme heat. All those hot days aren’t just a hazard for humans; they can also do a number on your car, both inside and out.

Taking some precautions before the mercury rises can help your vehicle survive the swelter.

Prep Your Car for the Heat

For obvious reasons, hot weather puts extra strain on the systems that keep your car’s engine and cabin cool. Making sure these systems are in good order will do more than just keep you comfortable. It will also protect your engine.

In the spring, be sure to inspect and top off your radiator coolant and consider having the system flushed if it hasn’t been serviced in several years. While you’re at it, make sure to top off or change other critical fluids, including your engine oil. Low or contaminated oil can lead to excess friction and heat—the last thing an engine needs in hot weather. Air and oil filters should also be changed to help your car run at peak efficiency.

If you notice that your air conditioning system isn’t putting out cold air, is blowing slowly, or giving off a musty smell, it might need to be serviced and recharged. Since the AC system is a closed loop, low refrigerant means there’s a leak somewhere that will need to be found and fixed as well.

High temperatures can also increase air pressure inside your tires, causing them to overinflate. That can lead to tire damage. So, grab a gauge and make sure your pressure is within the manufacturer’s specifications. Don’t forget to check your spare as well.

Daily Precautions

If you’ve seen a faded or cracked dash, sun-worn leather seats, and peeling, faded paint on an older vehicle, you know what years of direct UV exposure can do to a car’s interior and exterior.

Much like sunscreen protects your skin, shade shields your car’s paint, plastics, and rubberized parts from damaging UV rays. Whenever possible, it’s wise to park your car in a garage or at least in a shaded space. Staying off the road between 11 a.m. and 3 p.m.—when the sun’s rays are at their most punishing—adds another measure of protection.

In some parts of the country, full window tinting has become a popular way to cut down on UV radiation and protect car interiors. Expect to pay between $100 and $400 to have the film applied, but be sure to check your local laws before you commit, as full tinting may not be legal in some jurisdictions.

If you can’t or don’t want to opt for a tint job, consider using a simple, foldable window shade, which can lower the overall temperature in a sun-exposed car and can keep your dash from heating up like a furnace—one parked car in direct sun with a sunshade saw temperatures reach a scorching 171 degrees, and 206 degrees without a shade in place, which is nearly hot enough to boil water.

A Special Consideration for EV Owners

Electric vehicle (EV) drivers have an added hot-weather consideration—high temperatures can put a strain on EV batteries—and not just from all the power needed for air conditioning.

AAA’s Automotive Research Center found that temperatures above 95 degrees can knock almost 33% off an EV’s range. High heat can also speed up chemical reactions within batteries and shorten their lives. Many EV users regularly recharge their batteries to no more than 80%capacity to help them last longer—a practice even Elon Musk has endorsed and one that may be even more important during extreme heat.

Finally, if your EV has a pre-conditioning option to cool the interior while it’s plugged in, it’s a good idea to use it, as this will conserve the battery power you’d otherwise expend cooling your hot car down after you’ve hit the road.

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Andy Stonehouse
Andy Stonehouse literally fell into the world of auto writing while working as a ski-town journalist, and has not looked back since. A childhood spent dealing with the eccentricities of a 1976 MG Midget has made any subsequent auto experience a more safe and reliable drive. He has been blessed with nearby mountain trails and snowy roads in Colorado to do TV-adventure-styled test drives on a weekly basis.