What To Do If Your Car Overheats

Today’s cars have sophisticated cooling systems equipped with multiple heat sensors and computer-controlled electric fans designed to keep your engine running in any weather. But overheating can still happen. Continue reading on to learn the best ways to prevent an overheated car and steps you can take in the event that your car begins to run hot.

Why do engines overheat and how can I avoid it?

Engines overheat for many reasons. Generally, cars overheat because of a problem with the cooling system that doesn’t allow heat to leave the engine compartment. This is often due to a leak or blockage somewhere in the engine cooling system or other components. Other sources may be from a faulty or broken water pump or radiator fan, or from a clogged coolant hose.

Components like rubber hoses, gaskets, and water pumps can spring a leak with regular wear and tear, says Richard Reina, product training director of CARiD.com, an online auto parts seller. He adds that certain driving conditions, like stop-and-go traffic on a hot day, can put significant stress on the cooling system, causing it to fail. Fortunately, you can usually avoid this problem with regular maintenance by a certified mechanic, who will check your car’s coolant and oil levels and inspect hoses, fans, the thermostat, and other parts in the cooling system, Reina says.

But what do you do if your temperature gauge starts to climb toward “H” or the dashboard warning light flashes? “The steps you take could mean the difference between replacing a $20 thermostat and thousands of dollars in repairs,” says Reina.

What are signs of an engine overheating?

While every vehicle and situation can be unique, there are a few common signs to be aware of when your car engine is beginning to overheat:

• Steam (often looking like smoke) coming from the front of the vehicle under the hood.
• The engine temperature gauge in the dashboard or driver console spiking to “H” or moving into the red area of the gauge.
• Strange smells or odors emanating from the front of the car, particularly near the hood. Leaking coolant can often have a sweet smell, while oil leaks will typically produce a burnt odor.

Here is a list of items to have on hand in the vehicle if your car engine overheats:

• Small, basic tool kit
• Several quarts of oil
• 1 gallon of coolant (50/50 mix of antifreeze fluid and water)
• Towel
• Heavy-duty gloves

5 steps to take when you have an engine overheating:

1. Turn on the heater.

It sounds counterintuitive, but Reina recommends turning on the heater. It draws warmth away from the engine and into the passenger compartment, lessening the burden on the engine’s cooling system. In certain circumstances, that may be enough to reverse the overheating, he says. You’ll know it’s working if the warning light goes off or the temperature gauge returns to the neutral position.

2. Pull over.

If your car continues to overheat after you’ve been driving for a few minutes with the heater on, pull over and cut the engine off—it’s the safest and surest way to cool the engine, says Reina. If you have roadside assistance, now is a good time to call, as you may need a tow, Reina suggests.

3. Sit tight.

If you don’t have roadside assistance, be patient; it will take at least 15 minutes for the engine to cool. In the meantime, do not attempt to open the hood; the coolant in a car that has overheated may be in excess of 230 degrees, says Reina. Once the hood is open, there’s a risk of being sprayed with hot water or steam. “Your personal safety is most important,” he says. “Waiting for at least 15 minutes allows the hood, engine and leaking coolant to cool.”

4. Add coolant.

When you’ve waited at least 15 minutes and the hood is cool to the touch, put on gloves, open the hood, and locate the radiator cap (consult the owner’s manual if necessary), says Reina. Cover the cap with a towel and slowly push down and loosen it a quarter of a turn, to release pressure that has built up as a result of the coolant expanding when heated. Then fully open the radiator cap and slowly add coolant—half water, half antifreeze—until the liquid reaches the “full” line. You should also add coolant to the small, clear plastic overflow reservoir mounted to the side of the radiator, he says. Next, replace the cap and turn on the engine. “If the temperature gauge comes back to normal or the red warning light goes out, you can proceed with caution while keeping an eye on the temperature gauge or light,” says Reina.

5. Drive to a service station.

Adding coolant does nothing to address the problem that caused your engine to overheat in the first place, but it often allows you to drive safely to the nearest repair station. “A professional will need to inspect your car’s cooling system,” says Reina. While driving, keep an eye on the temperature gauge. And take notice of everything, like fluid under the car or steam under the hood. “This basic information will greatly help in the diagnosis,” Reina explains.

Download and print this PDF checklist of what to do—and what items to have on hand—in case of overheating.

Need help on the road? Easily request roadside assistance with the GEICO Mobile app.

By Patrick Rogers