Leaving your car baking in the sun when temperatures climb past 35 degrees Celsius (95 degrees Fahrenheit) is one of the worst things you can do to it. Yet every summer, millions of cars sit in parking lots, slowly cooking under relentless heat. The damage is real, and it adds up faster than most people realize.
When summer arrives and the mercury pushes past 30 to 35 degrees Celsius (86 to 95 degrees Fahrenheit) in the shade, your car suffers right along with you. In some places, temperatures can hit 40 degrees Celsius (104 degrees Fahrenheit) or higher. If you do not take some basic precautions, your vehicle will age faster, parts will fail sooner, and you will find yourself dealing with problems that could have been avoided.
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Researchers from Arizona State University and the University of California at San Diego School of Medicine conducted a study that should make every car owner think twice about where they park. They found that a car left in direct sunlight for just one hour on a day when the outside temperature is 35 degrees Celsius (95 degrees Fahrenheit) will see cabin temperatures soar to an average of 47 degrees Celsius (116 degrees Fahrenheit). The dashboard can reach a scorching 69 degrees Celsius (157 degrees Fahrenheit). The steering wheel hits around 53 degrees Celsius (127 degrees Fahrenheit), and the seats average about 51 degrees Celsius (123 degrees Fahrenheit).
Those are not just uncomfortable numbers. Those are temperatures that can warp plastic, crack leather, evaporate fuel, and put serious stress on every component inside and outside your car. Let us talk about what you can do to protect your vehicle when the heat is on.
Why Natural Shade Is Your Best Friend
The single best thing you can do for your car in hot weather is to park it in natural shade. When we say natural shade, we are talking about trees. Big, leafy trees that block the sun completely.
The difference is dramatic. A car parked under a tree might have an interior temperature of around 25 degrees Celsius (77 degrees Fahrenheit), while a car in direct sunlight can easily reach 50 degrees Celsius (122 degrees Fahrenheit) or more. That is a difference of 25 degrees, and it makes all the difference in the world.
Natural shade does more than just keep the cabin cool. It protects the paint from UV damage, prevents the dashboard from cracking, keeps the seats from fading, and reduces stress on the cooling system. If you have trees on your street or near your workplace, make it a habit to park under them. It is free, it is easy, and it works.
But we all know that is not always possible. Not every parking lot has trees, and not every street is lined with leafy cover. So what do you do when natural shade is not an option?
Artificial Shade Is Better Than Nothing
If you cannot find a tree, look for artificial shade. This could be a parking garage, a carport, or even the shadow cast by a tall building. These spots are not as cool as natural shade, but they are still a huge improvement over parking in direct sunlight.
Here is a tip that takes a little planning but pays off. Think about how the sun moves throughout the day. If you park in the morning and leave your car until the afternoon, consider where the shade will be later in the day, not where it is when you arrive.
For example, if you drive to work early in the morning, it might be fine to park in the sun initially if you know that by noon or early afternoon, a building will cast shade over that spot. The worst heat of the day happens in the afternoon, so if your car is in the shade during that window, you are ahead of the game. When you come back to your car at the end of the day, it will not be a furnace.
But what if there is no shade at all, natural or artificial? What do you do then?
How to Protect Your Car When You Have No Shade
Sometimes you have no choice. You are stuck parking in the sun. It happens. But you are not helpless. There are several things you can do to minimize the damage.
Tinted Windows Make a Real Difference
Window tint is one of the most effective ways to keep your car cooler. A quality tint blocks a significant amount of UV radiation and heat from entering the cabin. This keeps the interior cooler, protects the dashboard and seats from fading, and makes the car much more comfortable when you get back in.
Many people tint the rear windows and back glass, but if you can, consider tinting the front windows as well. Just make sure you stay within the legal limits in your area. Some places allow a light tint on the front windows, while others do not. Check your local regulations before you do anything.
There are also clear UV-blocking films that do not darken the windows but still block harmful rays. These are legal in most places and can be a good compromise if you want protection without affecting visibility or running afoul of the law.
Windshield Sunshades Are Simple and Cheap
A windshield sunshade is one of the cheapest and easiest things you can do to protect your car. These reflective shades sit inside your windshield and block the sun from hitting your dashboard and steering wheel. They fold up easily and take about five seconds to put in place.
The difference they make is huge. A dashboard that would normally reach 69 degrees Celsius (157 degrees Fahrenheit) might only hit 40 degrees Celsius (104 degrees Fahrenheit) with a sunshade in place. That is still hot, but it is a lot less likely to cause cracking and warping.
You can also get sunshades for the side windows and rear window. These are especially useful if you have kids or pets in the car, but they also help keep the overall cabin temperature down.
Cover Your Seats
This might sound old-fashioned, but covering your seats with a towel or light-colored cloth actually works. When I first saw people doing this, I thought it looked ridiculous. But after burning my legs on a black leather seat in the middle of summer, I changed my tune.
Leather seats, in particular, can get unbearably hot. The sun bakes them, and when you sit down, it feels like you are sitting on a hot stove. A simple towel or seat cover blocks the direct sunlight and keeps the leather much cooler. When you get in the car, you can just toss the towel in the back and go.
This also protects the leather from UV damage, which can cause it to crack and fade over time. It is a small thing, but it adds years to the life of your upholstery.
Crack the Windows Slightly
Leaving your windows cracked open about an inch or two allows hot air to escape and lets fresh air circulate. This prevents the cabin from turning into a pressure cooker. The difference is noticeable. A car with the windows cracked will be several degrees cooler than one that is sealed up tight.
Some people worry about security. And yes, you do not want to leave your windows wide open. But a small crack is not enough for someone to reach in and unlock the door, and it is not going to invite theft. Modern car alarms and locks are effective enough that a thief is not going to waste time trying to jimmy a window open an inch. Use common sense, but do not be paranoid.
How Heat Destroys Your Fuel
Here is something most people do not think about. Heat causes gasoline to evaporate. You have probably noticed a hissing sound when you open your fuel cap after the car has been sitting in the sun. That is pressure from fuel vapors building up inside the tank.
Studies have shown that a car parked in direct sunlight can lose about one liter of gasoline per week just from evaporation. That is not a huge amount, but over time it adds up. It also means your fuel economy takes a hit in the summer, and not just because you are running the air conditioner.
In older cars with metal fuel tanks, this can cause even bigger problems. The tank can swell or deform if the pressure relief valve is not working properly. This is rare, but it happens. If you have an older vehicle, it is worth checking the condition of your fuel tank and vapor recovery system before summer hits.
One simple trick is to not tighten your fuel cap all the way after filling up. Leave it just slightly loose so pressure can escape. This is not something you should do all the time, but if you know your car is going to sit in the sun for hours or days, it can help.
Why Your Dashboard Cracks in the Heat
Dashboards are made of plastic. Some are made from high-quality materials that can handle heat. Others are made from cheap plastic that was never designed to withstand years of UV exposure and extreme temperatures. If you drive a budget car, chances are your dashboard is not made from the good stuff.
When plastic is exposed to intense heat day after day, it becomes brittle. It dries out, hardens, and eventually cracks. This is especially common on dashboards, air vents, and other interior trim pieces. Once the plastic cracks, there is not much you can do short of replacing the whole piece, which is expensive and often difficult.
Heat also causes plastic parts to expand and contract. Over time, this movement creates gaps and loose fittings. That is where those annoying rattles and squeaks come from. You drive over a bump and hear a noise somewhere in the dashboard, but you cannot figure out where it is coming from. That is heat damage.
Protecting your dashboard is simple. Use a sunshade. Keep the car out of direct sunlight when possible. And consider using a dashboard protectant spray that contains UV blockers. These sprays do not stop the heat, but they do help prevent the plastic from drying out and cracking.
Leather Seats and Steering Wheels Take a Beating
Leather looks great, feels luxurious, and is a pain to maintain in hot weather. The sun dries out leather, causing it to crack and fade. If you do not condition your leather regularly, it will not last.
But here is the bigger problem. When you get in a hot car and grip the steering wheel with sweaty hands, the salt from your sweat gets into the leather. Over time, that salt draws moisture out of the leather, drying it even more. This creates a cycle. The sun dries the leather, you touch it with sweaty hands, the salt dries it further, and cracks start to form.
To prevent this, you need to clean and condition your leather seats and steering wheel regularly. Use a cleaner to remove sweat and oils, then apply a conditioner that adds moisture back into the leather. Do this every few months, or more often if you live in a very hot climate.
And again, covering your seats and steering wheel when the car is parked can make a big difference. It blocks the UV rays and keeps the leather cooler, which slows down the aging process.
Rubber Parts Dry Out and Crack
Rubber does not like heat. Gaskets, seals, hoses, boots, and bushings are all made from rubber or rubber-like materials, and all of them degrade faster in hot weather. The heat dries them out, makes them brittle, and eventually they crack or tear.
This is especially true for parts under the hood and underneath the car. Suspension bushings, CV boot joints, brake hoses, and vacuum lines all take a beating in the heat. The rubber bakes, loses its flexibility, and starts to fail.
You cannot really prevent this from happening, but you can slow it down. Regular inspections help. Look for cracks, dry spots, or signs of wear on rubber parts. Replace them before they fail completely. And if you are doing maintenance before summer, consider applying rubber protectant to hoses and seals. It is not a miracle cure, but it does help.
Your Engine Can Overheat Even If It Is New
Most people think only old cars overheat. That is not true. Even a brand new car can overheat if the conditions are bad enough. Sitting in traffic on a hot day with the air conditioner running is one of the worst scenarios for your cooling system.
Here is why. When you are moving, air flows over the radiator and cools the engine. But when you are stuck in traffic, there is no airflow. The only thing cooling the engine is the radiator fan, and it has limits. Add in the fact that the air conditioner compressor is running, which puts extra load on the engine, and you have a recipe for overheating.
The asphalt itself can reach temperatures over 100 degrees Celsius (212 degrees Fahrenheit) in the summer. The engine hood absorbs that heat, and the temperature under the hood can climb to 150 or even 160 degrees Celsius (302 to 320 degrees Fahrenheit). The cooling system is working overtime, and if anything is even slightly off, the engine can overheat.
The best thing you can do is make sure your cooling system is in top shape before summer. Check the coolant level, inspect the hoses for cracks, make sure the radiator cap is sealing properly, and test the radiator fan. If anything is worn or marginal, replace it. It is cheaper than replacing an engine that overheated and warped the head.
And if you do find yourself stuck in traffic on a scorching day and the temperature gauge starts to climb, turn off the air conditioner and turn on the heater. Yes, it will be miserable, but the heater pulls heat away from the engine and can help prevent overheating. It is a temporary fix, but it works.
How to Keep Your Car Cool While Driving
Parking in the shade is great, but what about when you are actually driving? Here are a few tips to keep your car as cool as possible when you are on the road.
Start With the Windows Down
When you first get in a hot car, roll down the windows and drive for a minute or two before turning on the air conditioner. This lets the super-heated air escape. If you turn the air conditioner on immediately, it is just going to recirculate hot air, and it will take much longer to cool down.
Once the initial blast of hot air is gone, roll up the windows and turn on the air conditioner. Set it to recirculate mode so it is cooling the air that is already inside the car, not pulling in hot air from outside.
Park Facing Away From the Sun
If you know you are going to be parked for a while, try to park so the front of the car is facing away from the sun. This keeps the windshield in the shade, which means the dashboard and steering wheel will not get as hot. It is a small thing, but it makes a difference.
Use a Remote Starter If You Have One
If your car has a remote starter, use it. Start the car a few minutes before you get in and let the air conditioner run. By the time you walk to the car, it will already be cooling down. This is especially useful if you have kids or elderly passengers who are more sensitive to heat.
What Happens to Paint in the Sun
Your car’s paint is designed to withstand the elements, but it is not invincible. UV rays break down the clear coat, which is the protective layer on top of the paint. Over time, this causes the paint to fade, lose its gloss, and eventually start to peel.
Dark-colored cars suffer the most. Black, dark blue, and dark red cars absorb more heat and show fading more quickly than lighter colors. If you park in the sun every day, you will start to notice the paint looking dull and chalky within a few years.
The best way to protect your paint is to keep the car out of the sun. But if that is not possible, regular washing and waxing help. Wax adds a layer of protection over the clear coat and helps reflect UV rays. Some people also use ceramic coatings, which are more durable and offer better protection than traditional wax.
Battery Life Gets Shorter in the Heat
Most people think cold weather is hard on batteries. It is, but heat is actually worse. High temperatures cause the battery fluid to evaporate, which damages the internal structure of the battery. This shortens its lifespan significantly.
A car battery that might last five years in a moderate climate might only last three years in a place with very hot summers. There is not a lot you can do about this except park in the shade when possible and have your battery tested regularly. If it is getting weak, replace it before it leaves you stranded.
Tire Pressure Changes With Temperature
Heat causes the air inside your tires to expand. That means your tire pressure goes up in hot weather. Overinflated tires wear unevenly, reduce traction, and are more prone to blowouts.
Check your tire pressure regularly in the summer, and do it in the morning before you drive. Tire pressure should be checked when the tires are cold, because driving heats them up and gives you a false reading. If your tires are overinflated, let a little air out. If they are underinflated, add air until they are at the recommended pressure, which you can find on a sticker inside the driver’s door or in the owner’s manual.
Air Conditioning Puts Extra Load on the Engine
Running the air conditioner makes your engine work harder. The compressor is driven by a belt connected to the engine, and it takes power to run it. That means your fuel economy goes down when the air conditioner is on.
But here is the thing. At highway speeds, rolling down the windows creates drag, which also reduces fuel economy. So which is better? Studies have shown that at speeds above about 50 to 60 kilometers per hour (30 to 40 miles per hour), it is more efficient to use the air conditioner and keep the windows up. At lower speeds, it is better to roll down the windows and turn off the air conditioner.
Use this knowledge to your advantage. If you are driving around town, windows down is fine. If you are on the highway, use the air conditioner.
Simple Steps to Protect Your Car in Summer
Let us summarize everything we have talked about into a simple list you can follow.
- Park in natural shade whenever possible.
- Use artificial shade if natural shade is not available.
- Install window tint to block UV rays and reduce heat.
- Use a windshield sunshade every time you park.
- Cover your seats with a towel or cloth if you have leather.
- Crack the windows slightly to allow hot air to escape.
- Check and maintain your cooling system before summer starts.
- Inspect rubber hoses, belts, and seals for cracks and wear.
- Clean and condition leather seats and steering wheels regularly.
- Wash and wax your car to protect the paint.
- Check tire pressure regularly and adjust as needed.
- Have your battery tested and replace it if it is weak.
- Use the air conditioner wisely to balance comfort and fuel economy.
These steps are not complicated, and most of them cost little to nothing. But they can save you hundreds or even thousands in repair costs down the road.
Heat Damage Adds Up Over Time
One hot day is not going to destroy your car. But years of exposure to extreme heat will. The damage is cumulative. A little cracking here, a little fading there, a hose that fails a bit sooner than it should have. All of it adds up.
The key is to be proactive. Do not wait until something breaks. Take steps now to protect your car from the heat. It is easier and cheaper to prevent damage than it is to repair it.
Do Not Underestimate the Sun
The sun is powerful. It provides light and energy, but it also destroys. Your car is built to handle a lot, but it is not indestructible. Every material in your car, from the paint to the plastic to the rubber, has limits. When you expose those materials to extreme heat day after day, they break down.
Treat your car with a little care, and it will last longer, run better, and be more comfortable to drive. Ignore the heat, and you will pay for it in the long run. The choice is yours.