What Happens When a Car Overheats?
We’ve all seen it—a driver stranded on the side of the road, perplexed as their vehicle stalls and smokes. You may have even been there yourself.
There are a variety of reasons for a car overheating. It most commonly happens during the summertime in the warm weather, but it’s possible any time of year. Although there are ways to prevent a car from overheating, no one is totally immune to issues with the cooling system. Here are a few potential reasons your car is overheating:
What Causes a Car to Overheat?
1. Your engine coolant is low
The most likely culprit of your car overheating has to do with your liquid coolant. Most modern cars have a liquid-cooling system—whereas older cars are air-cooled.
Coolant, a mixture of antifreeze and water, takes on heat to prevent your car from overheating. It has a very low freezing point and extremely high boiling point in order to hold the maximum amount of heat. Your vehicle’s cooling system uses pressure to increase the boiling point even further (similar to how water’s boiling point is higher in a pressure cooker).
Coolant is circulated through the pipes and passageways of your engine, cooling the most critical parts. It then passes through the radiator, where the heat is transferred from the fluid to the air blowing out of your exchanger.
When your coolant is running low, the engine can overheat or even seize up. If the metal gets hot enough, a piston can weld itself into the cylinder. If this happens, your engine is likely destroyed.
2. You have a leak in your cooling system
There are a few indicators that you’re experiencing a coolant leak. Your reservoir tank might be lower than it should be, or you might see or smell a pool of coolant collecting under the vehicle.
Coolant leaks can happen if you have a leaky radiator cap or an internal or external leak. An internal leak is a likely cause if you notice that your coolant level does not stay constant, but there aren’t any visual signs. An external leak will be evident just by looking under your car — this can happen at the water pump, engine freeze plugs, and heater core.
Not sure if the liquid under your car is coolant or not? Coolant is typically brightly tinted (green, yellow, pink or red) and has a sweet smell.
The experts at Virginia Tire & Auto can quickly determine where your coolant leak is coming from and recommend the appropriate repairs.
3. Your thermostat is malfunctioning
Thermostats prevent engine wear, emissions and deposits. Located in between the car’s engine and radiator, the thermostat blocks the coolant until the engine has warmed up to its operating temperature—this typically happens at about 200 degrees Fahrenheit. At that point, the thermostat opens and allows the antifreeze to reach the engine at the right time.
If your thermostat is malfunctioning and displays a false reading (i.e. tells you that your car’s temperature is normal when it’s too hot), the coolant is not released and the car becomes progressively hotter. If this occurs continually, it can cause stalling and billows of smoke.
4. Your motor oil is low
Motor oil helps take heat away from your car’s engine and reduces friction and wear. It also helps keep the metals lubricated and picks up damaging contaminants. If it’s too low or too dirty, this can cause your engine to heat up faster than normal.
Read: 6 Essential Car Fluids to Check Regularly
5. You have a broken water pump
The water pump is what circulates coolant through the system. (Back in the “old days,” coolant was simply water—hence the name “water pump.”) If the water pump is broken, the coolant won’t circulate, leading to an overheating engine.
6. The radiator is damaged
After picking up heat from the engine, coolant passes through tubes in the radiator to cool down. Metal fins attached to the tubes collect the heat, which is then taken away by air moving across the radiator.
The radiator is typically located at the front of the vehicle so that cool air can flow through the grille while you’re driving and move hot air away. When you’re stopped, the radiator fan turns on to keep the air moving.
If debris is blocking the airflow, the radiator is damaged or the radiator fan isn’t working, then you’re cooling system won’t work properly and the engine temperature will rise.
What You Should Do if Your Car Overheats:
Signs that your engine is overheating include:
- The engine temperature gauge moved to the red area of the gauge (H).
- The engine temperature warning light is on
- Steam (looks like smoke) coming from under the hood
- Strange smells or odors coming from under the hood
This is not an issue to ignore—take these critical steps immediately to prevent damage from overheating:
1. To cool off your engine, turn up the heat! It seems counterintuitive, but to help transfer heat from the engine bay, turn on your heater and blower to the max and roll down the windows.
2. Pull over to a safe area as soon as possible and turn the car off. This is a good time to call your preferred roadside assistance provider, as you’re likely to need a coolant top-off or a tow.
3. After the car has been off for at least 15 minutes, you can open the hood of your car and check the coolant level. Opening the hood before the car has cooled could result in burns/injuries from spewing steam or smoke.
You can start driving again if the coolant level looks normal and the engine has returned to its normal operating temperature. Keep an eye on the temperature gauge and make plans to stop in at your local Virginia Tire & Auto for a quick diagnosis ASAP.
If the coolant level is low or the car won’t start, you’ll need to top off your coolant before you can start driving again and/or have the car towed to the repair shop.
(Need roadside assistance? Virginia Tire & Auto offers up to $200 in complimentary roadside assistance coverage for 365 days after your most recent service. Learn more.)
How to Prevent Overheating
The best way to prevent overheating is to keep up with your regular maintenance schedule. Some car models need a coolant flush every 30,000 miles, but others can go more than 100,000 miles between coolant flushes. Check your owner’s manual to be sure.
Regular oil changes help keep your engine at peak performance and prevent overheating. Plus, at Virginia Tire & Auto, our 25-point oil change service includes checking and filling (if necessary) your coolant.
Read: The Car Maintenance Checklist Every Driver Needs
Having Car Trouble?
Bring your vehicle to Virginia Tire & Auto! Our experts will diagnose the issue and make sure you understand any necessary repairs or replacements. Schedule a visit at your local Virginia Tire & Auto today!