Type to search

Why is My Car Overheating?

Hot summer days can mean more potential car issues. Learn the why, what, and how when it comes to reasons your car may be overheating before it’s too late.

You Aren’t the Only One Feeling the Heat

It’s almost impossible to beat the heat on those hot summer days. I know I’m basically baking alive in over 100-degree heat with a fan directed at myself, sweating, and trying to stay hydrated with a half-gallon of water. However, imagine if those cooling luxuries weren’t possible. No cool drink of water, no breeze from the fan, and you can’t even sweat. You’d probably overheat and pass out right? That ungodly experience can happen with your car too. Cars utilize specially designed cooling systems to keep their engines cool while running even during those blistering summer days. Yet they too can experience overheating when something goes wrong with that cooling system. It’s not uncommon for older cars to start steaming under the hood and have the check engine light pop on, so let’s make sure you know what’s happening and how to handle it before it happens to you. If you stumbled here after Googling “why is my car overheating?”, then I guess there’s no better time than the present to find out.

What Causes a Car to Overheat?

Overheated vehicle
Overheated vehicle

As I stated above, cars can overheat when something goes wrong with their cooling system or even due to a neglected maintenance item. Engines naturally generate a lot of heat when running and typically run at an optimal temperature between 195 and 220 degrees Fahrenheit. Engineers have created ways to keep those temperatures in check in a number of ways, but they aren’t foolproof. Once something goes wrong, the engine temp begins to climb past its normal operating temperature due to the built-up pressure or inability to dissipate heat. When the engine reaches these overheating levels, it will expel steam from wherever it can, throw error codes to your car’s computer, and start to damage the car’s engine.

What Should I Do if My Car Is Overheating?

AC Knob
AC Knob

So, what should you do if you believe your car is beginning to overheat? First, turn off the air conditioner. I know you’ll probably start to feel the summer heat now, but this will reduce any unnecessary load on the engine. Next, flip on the heat full blast. Things are only sounding worse when it comes to comfort at this point, however, this will help pull heat away from the engine bay to keep it under control for a little longer. Lower the windows to help yourself and the car further cool off. You’ll then want to carefully yet quickly pull over when you safely can and shut off the engine.

Keep an eye on the temperature gauge while you let the engine sit for a bit so that it may cool down. This can take about 15 minutes depending on the situation, but patience is key. Do not open the hood of your car until it cools down. There’s a lot of pressure and heat going on when a car overheats that could seriously burn you if not handled carefully, so you’ll want to steer clear of that area and keep it covered till the car naturally cools down. Also, keep your cool during this situation. I know that having to deal with a steam car isn’t an ideal situation, but beating on the body panels in frustration on the side of the road isn’t going to help anything and isn’t safe.

Temperature guage
Temperature guage

While you wait for the temperature to drop, you’ll want to phone a friend or a tow truck to help get your car to a repair shop. If you think you can limp to a nearby shop, you’ll want to let your car cool down as much as possible. After waiting for the engine to cool down, check and try to add some coolant if possible. This can help a lot here by both adding a little range before the car overheats again and protecting the engine somewhat in its current state.

Carefully restart the engine once everything is looking under control and drive straight to the nearest repair shop or your/your friend’s garage (whichever is closer). Keep an eye on the gauges and warning lights, making sure to follow the same steps if the car happens to overheat again. Keep in mind, further pushing an overheated engine can lead to additional damage, so don’t be afraid of taking that tow as it can be cheaper than a new engine in the grand scheme of things. Also, don’t keep driving a car daily that’s repeatedly overheating, this will only create more problems that will eventually lead to the car’s early demise.

Why Is My Car Overheating?

Looking to diagnose why your car may be overheating? It can be as simple as a leak or due maintenance, but you could also be looking at some extra work under the hood. Here are some key areas that can lead to overheating you should take note of.

Low on Coolant

Adding coolant
Adding coolant

Coolant helps regulate and reduce the temperature of the engine through the radiator. If your car is low on coolant, it can lead to overheating. One way to fix this is to find the coolant reservoir tank and refill or top it off to bring it back to the manufacturers recommended levels. When adding new coolant to an empty system, use a 50/50 mixture of coolant and water.

Problems with the Radiator

Radiator
Radiator

The next area of note is the radiator and its components. If something goes wrong with the radiator then there’s nothing to keep the engine at the correct operating temperature. There may be some air flow cycling into the engine bay while driving, but that’s like running laps to cool down. If you find that the system is low or almost empty on coolant, then there may be a leak in one of the systems hoses or fittings.

You can identify a leak by looking for moist spots or puddles underneath the vehicle and then look at the hoses above that area to see if you can identify the culprit. A helpful hint when accessing if it is coolant that is leaking is by taking note of the leaking fluid’s smell and color. Coolant has a sweet smell and comes in bright colors like blue, green, and orange.

Radiator pressure test kit
Radiator pressure test kit

There are also pressure leak testing kits you can attach to the radiator cap spot to help find a leak. If there is a noticeable leak while performing a pressure test on the system, you’ll see coolant start to come out of problem spots in the radiator, the connected hoses, or fittings. If you can’t identify the leak from the pressure test, then it could be the radiator cap itself. Yes, the cap may just seem like a minor part to the radiator assembly, but it holds a lot of the pressure in and can be the source of your problem if it begins to fail.

If you’re overheating and there doesn’t seem to be a noticeable leak from the system, then maybe the radiator fans aren’t working. To figure out this possible issue, start the car, crank the air conditioning on full blast, and take note of the fans on the back of the radiator. If one or both aren’t spinning, then you’ll need to replace them accordingly.

Radiator fans
Radiator fans

Fans seem fine but still having issues? Make sure the radiator hoses haven’t collapsed, as a vacuum may have been created in the system and partially closed them. If a hose collapsed, then it restricts coolant flow through the system like having a kink in a garden hose. This vacuum could have happened due to a faulty radiator cap, blockage somewhere in the hose from buildup in the coolant, or the radiator itself could have a clog.

If you find that there aren’t leaks, there’s plenty of coolant, the fans are working, and there aren’t any blockages, then it could come down to replacing the radiator itself. Over time these things just get so corroded and worn out inside that they can’t cool fast enough anymore. Before you go ahead with tossing the old radiator and dropping in a new one though, check that it isn’t one of the possibilities below.

Broken Thermostat

Car thermostat
Car thermostat

Everything you’ve checked seems fine so far yet the car still overheats? Could be a bad thermostat. A car’s thermostat helps regulate the engine’s temperature. When the car is trying to reach its operating temperature, the thermostat remains closed restricting the flow of coolant. Once the car reaches the correct temp, the thermostat opens and lets the coolant flow throughout the system. If the thermostat gets stuck closed, then coolant can’t properly cycle when it’s supposed to leading to an overheating vehicle.

Broken Water Pump

Water Pump
Water Pump

A car’s water pump helps cycle coolant throughout the engine while running. If this water pump isn’t powered or breaks, then the coolant can’t circulate through and leads to overheating. Coolant that hasn’t been changed in a while and has a bunch of built-up junk circulating through the system can also hurt the performance of the water pump. If the water pump is getting gummed up or the coolant pathways are being restricted by buildup, then the system won’t get enough coolant to cool down the engine.

Timing Belt Problems

Timing Belt
Timing Belt

Have you checked your timing belt? This piece of rubber on the engine’s pulley system could be the reason you’re overheating. If the timing belt is loose, frayed, or slipping, then it may not be fully powering the water pump when the car is running. Try replacing the belt and see if the water pump pushes coolant through the system better and keeps the car cool.

Low on Oil

Checking engine oil level
Checking engine oil level

What’s one of the biggest routine maintenance items all car owners should do? If you didn’t say “change your oil” then book that appointment today. But yes, oil can help reduce the friction of the moving engine parts like the pistons which in turn can reduce its heat. If your car is low on oil or is running with degraded oil, it’ll probably run into more problems than heat, but it can add to the problems that lead to overheating.

Blown Head Gasket

Head gasket
Head gasket

Gone through everything and you still can’t identify the issue? May have to tear down the engine as a blown head gasket can be the source of the car overheating. Before you break out the tool set, try a combustion leak testing kit. This specialized kit attaches to the radiator cap spot and uses a color changing liquid that reacts when there is a leak found in the system. If the color changes, you’ve got a problem.

How Can I Stop My Car from Overheating?

Car maintenance
Car maintenance

Now, go ahead with that road trip through the desert this summer if you want. Just try not to push your car like it’s in the Baja or something. Otherwise, you’ve got all the knowledge you may need if your car were to overheat.

The best way to stop a car from overheating is by performing routine maintenance checks and to be prepared. Consistently check your coolant levels about twice a year. Don’t overdo it with the air conditioning when it’s record-breaking temperatures outside. Take a look through your car’s manual to see how often the coolant should be flushed. Keep an eye on the temperature gauge while driving and give the car a break when it starts to climb too high. It also can be helpful to have some emergency coolant in the trunk should the opportunity arise.

Related How To Articles

How to Build Your Credit with a Car Loan

Driving In Fog

The Guide To Vehicle Bicycle Racks

Tags:
Jesse McGraw

Jesse McGraw brings his life-long car obsession into his writing. A fun childhood that involved growing up around race tracks, working on a rusty ‘99 Dodge Dakota held together by zip ties, and collecting Hot Wheels developed into a strong appreciation for automotive history. If there is an old, obscure, or rare car, he wants to know about it. With a bachelor's degree in Web Development & Design from Dakota State University, Jesse can talk shop about car or computer specs, focusing on classic cars, imports, and car culture.

  • 1

Leave a Comment

Your email address will not be published. Required fields are marked *

Share
Tweet
Pin