What Happens When Your Car Overheats?


As you’re driving down the road, you may suddenly notice the temperature gauge pointing to the H (for high). Also, your air conditioner may stop working, and there might be white smoke coming from the engine. Those are signs that your car is overheating. 

When your car overheats, that means not enough coolant is getting to the engine. The coolant keeps the motor at a temperature low enough to operate properly. Overheating can cause blown head gaskets, warped cylinders, or total the engine. 

It’s essential to keep your eye on an engine that looks like it will overheat. Read on to determine what happens when your car overheats and how to handle it. 

What Are the Signs of a Car Overheating?

To understand what happens when a car overheats, you must first understand what signs indicate overheating. 

Here are the signs your car is overheating: 

  • Leaking fluids 
  • Loss of air conditioning 
  • Loss of power 
  • White smoke in the tailpipe 
  • White smoke under the hood 

Leaking Fluids

Fluid loss is the first sign your vehicle is at risk of overheating. A radiator leak means the coolant is unable to cool the engine. If there’s a puddle under your car, check for leaks and cracks. When the leak is near the front of your car, chances are the engine may be the problem. 

Read: Why Car Overheats?

Loss of Air Conditioning

The engine should retain any ability to stay cool. Loss of air conditioning means the motor cannot afford to put out cool air. Additionally, you might feel the A/C blowing hot, which is the engine’s way of blowing off heat away from itself and acting as an additional protective measure. 

Loss of Power

When the engine cannot cool itself, it will lose the ability to accelerate. You may notice the engine starting to decelerate, and you will need to pull over as soon as possible. Otherwise, a faulty engine may cause a severe accident and cause you far worse problems than overheating. 

Read: Why Car Speedometer Not Working?

White Smoke in the Tailpipe

When you see white smoke in the tailpipe, that means the engine is burning the coolant somewhere in the exhaust system. If the coolant is boiling through the exhaust system, it’s less likely there will be fluid leaks under the vehicle — which, as I’ve explained above, is a sign of overheating. 

White Smoke Under the Hood

White smoke under the hood means coolant is flowing through a broken head gasket and burning up in the engine. A fractured head gasket could result in coolant mixing with the exhaust or oil. If the oil seeps into the cooling system, that could be dangerous for your vehicle. 

Read: How To Get Roaches Out of Car?

Why a Car Can Overheat?

When your car overheats, that can mean a lot of things. Some of the reasons a car overheats are:

  • You ran out of coolant. This is a relatively easy fix if your vehicle hasn’t suffered significant damage yet. You can refill the coolant or use water as a temporary solution. Note my use of the word “temporary”: If you’re not in a pinch, it’s better to use fluids specially designed for car engines whenever possible. 
  • The radiator cracked. Unfortunately, car parts can crack or break. Under normal conditions, the radiator is cooling a scorching engine. Excess heat can cause the metal to expand and the seams to split, resulting in a coolant leak. 
  • The radiator fan is not working. The radiator cools the coolant using the radiator fan. If the fan isn’t working or is broken, the radiator cannot adequately cool the fluid. 
  • The coolant passages are clogged. Fluid and debris can cause blockages in the coolant pathways. There could be a blockage somewhere in the cooling system if there’s no issue with the fluid levels, the radiator, or the fan. 
  • The thermostat is broken. When the thermostat fails in the closed position, the coolant cannot flow freely from your radiator to the engine to perform proper cooling. 

If the radiator is not cooling the coolant, or the coolant is not getting to the engine through the head gasket, your car can overheat and leave you stranded on the side of the road. In that case, you may need to replace the engine. 

Taking your vehicle for regular maintenance and oil changes will help you recognize potential issues before they become expensive problems. 

What To Do if Your Car Overheats?

Turn Your Heater on Full Blast and Pull Over Immediately

The most important thing you can do when your vehicle overheats is to pull over immediately. If you cannot stop right away, turn on your car’s heat full blast and roll down your windows. Make sure to pull over as soon as possible, and to do so in a safe place away from traffic. 

Check the Fluids

Pop your vehicle’s hood to allow the smoke to escape and the ambient air to cool overtop the engine. While you’re under the hood, check for leaks, but be careful not to touch anything until the engine has cooled. Otherwise, you’ll risk painful burns. 

Release the Pressure

If your radiator cap has a pressure relief valve, open it to release steam and built-up pressure. You can also use this feature to help cool the motor. Note that not every radiator cap has a cooling ability, so be sure not to open the radiator cap itself before the engine has fully cooled. 

Call for Help

If the coolant is low or empty, fill the radiator with coolant. Water will work in a pinch, but it’s not a long-term solution. If the additional coolant or water doesn’t fix the problem, call for a tow truck and take your vehicle to a mechanic. A trained mechanic should be able to identify the problem. 

Read: What Cars Have Apple CarPlay?

How To Prevent Your Car From Overheating?

Nationwide Insurance lists 11 steps to prevent your car from overheating, some of which include the following:

  • Monitor the temperature gauge. If the temperature reads high, pull over and turn off the engine to allow it to cool. 
  • Park in the shade or garage. Parking in a shady or covered area will prevent the vehicle from heating up before you turn it on. 
  • Turn the heater on to let the engine cool off. Allow the engine to blow off the heat by turning your heater on full blast. Roll down the windows, so you don’t overheat yourself. 
  • Replace your car’s battery. Nationwide Insurance says that if your battery isn’t working at optimum capacity, your car may be feeling the effects of low power and trying to compensate by working harder. This process could lead to overheating. 
  • Take your car in for regular maintenance and inspection. Let a mechanic do a thorough inspection when taking your vehicle for an oil change. They may be able to find issues you cannot see right away. 
  • Top off your fluids. Carry water or coolant in your trunk. This way, you can top off fluids as you need to. 

What if You Continue Driving an Overheating Car?

Sometimes, drivers think they can make it to their destination even though the vehicle is overheating. Continuing to drive is not the best option for many reasons. 

If you continue to drive an overheating car, you risk permanent damage to the engine. Also, replacing an engine is costlier than replacing parts that have broken and caused the vehicle to overheat. Most importantly, your car could catch fire. 

The most significant concern for some drivers is that calling a tow truck or going to a mechanic will be too expensive. However, having your car towed may save you thousands of dollars in the long run. Replacing a broken head gasket or radiator will be far less costly than replacing the entire engine. 

Moreover, your safety is critical. Driving an overheating vehicle is damaging to the car, and dangerous for you. The heat from the engine will continue to rise until the vehicle shuts down completely or gets hot enough to ignite. A car fire can also be life-threatening to you and the other drivers around you. 

Read: Car AC Compressor Replacement Cost

Key Takeaways

  • Recognize the signs of overheating early and pull over immediately. 
  • Signs of overheating include a high-temperature gauge, loss of power, and smoke from the tailpipe or under the hood. 
  • Make sure to check your fluid levels regularly. Replenish fluids when they’re low. 
  • Schedule regular maintenance for your vehicle so a trained mechanic can spot issues early. 
  • Don’t try to drive a vehicle that continues to overheat. Driving an overheated vehicle is unsafe for you and can damage the engine. It’s also expensive to replace a car engine.

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