9 Reasons Your Car Overheats (And 5 Things You Can Do About It)
Internal combustion engines produce energy through many small, controlled explosions. The combustion process generates a tremendous amount of heat, so a carefully designed cooling system is necessary for the engine to run properly.
Without a cooling system, the engine will quickly overheat and can cause permanent damage. In extreme cases, overheating can cause the engine to fail completely. Repairing a broken engine can cost nearly five figures in today’s market. That’s why it’s important to catch this problem early before it becomes serious. Moreover, you need to understand what causes your car to overheat so you know how to solve the problem and prevent it from recurring in the future.
Avoid Overheating Your Engine
Most automotive experts say that damage can occur to your vehicle’s mechanical components if your engine exceeds about 250°F. However, every engine and coolant mixture is different. Pure water (without antifreeze) boils at about 248°F. Using a 50/50 antifreeze mix raises the boiling point to over 265°F.
Your temperature gauge will tell you that your engine is too hot. You may also see the engine warning light come on on your dashboard. In extreme cases, you may see steam coming from the engine. The steam indicates that the coolant is boiling and can no longer effectively cool your engine.
Why does my car overheat?
There are many reasons why a car overheats. Therefore, you need to troubleshoot or diagnose to find the cause. Here are some common causes of overheating.
1) Coolant Leak
One of the main causes of a car overheating is coolant leaking from the cooling system hoses. These hoses are responsible for transporting coolant from the cooling system to the engine. If these hoses become damaged or worn, even the smallest hole will leak coolant. When that happens, there will not be enough coolant circulating through the engine, and overheating will occur in a short time.
To get to the nearest auto repair shop quickly, you need to fill the cooling system with enough coolant so that you can get there without overheating. This may require you to stop a few times to check the coolant. Be careful to never open a pressurized cooling system while the engine is hot.
2) Airlock (low coolant warning)
When coolant leaks, more air than coolant collects in the cooling system. All this accumulated air forms a large bubble called an airlock.
This airlock prevents the remaining coolant from circulating further through the engine, causing the engine to overheat even more. This is a big reason why coolant leaks need to be addressed before they cause an airlock.
3) Low Concentration of Antifreeze (Engine Coolant)
If you live in a northern region where it is cold and the outside temperatures drop below freezing, a gel may form in the coolant while it remains in the engine. This can happen if the concentration of antifreeze is too low compared to the amount of water in the coolant mixture. A general rule of thumb is to mix antifreeze and water 50/50.
Gel in the cooling system can cause clogs that prevent coolant from circulating in and out of the engine. This can cause the engine to overheat.
4) Water Pump Failure
Another common cause of car overheating is a failed water pump. The water pump is the main component that circulates coolant through the engine, cooling the components. Unfortunately, water pumps wear out and can eventually fail if the impeller no longer works. It won’t be long before the engine overheats and causes even bigger problems for your vehicle.
5) Faulty Thermostat
Every vehicle’s cooling system is equipped with a thermostat that controls the amount of coolant that enters the engine. When the engine is cold, the thermostat keeps the chamber closed, preventing coolant from entering the engine.
Engines are designed for a specific operating temperature, so when you start your engine, the thermostat is initially closed. Normal operating temperature is between 190 and 220°F (approximately 100°C). Engines run best when they reach this temperature as quickly as possible.
When the engine temperature reaches a certain threshold temperature, the thermostat opens the cooling system, allowing cooler coolant to flow from the radiator to the engine. Typically, the thermostat opens when the engine reaches about 200°F. If the thermostat stays closed, the engine can overheat because the radiator cannot cool it.
6) Heat Buildup
Heat buildup occurs when your cooling system accumulates heat faster than it can dissipate it. This can happen when your air conditioner is running in very hot weather or when you are under constant heavy load. When you are climbing a steep mountain road or driving your car on a race track, your engine is constantly under great stress.
If your cooling system is not designed to withstand the sustained stress in these conditions, you will notice the temperature start to rise. If your cooling system is working properly, you will notice the temperature drop as soon as you take your foot off the gas for a while.
7) Bad Intake Manifold Gasket or Head Gasket
Carbon buildup on the wall of cylinder number 4 (right) is a classic sign of a leaking head gasket. A bad head gasket or intake manifold gasket can show up in a variety of ways. Usually, you will see air in the cooling system. A bad head gasket can also show up as an oil leak.
If you suspect that your head gasket is bad, a leak test can confirm this. A leak test involves blowing compressed air into each spark plug hole. Where this air is leaking from can help you quickly determine the overall condition of your engine. A cooling system air leak is a strong sign of a blown head gasket.
8) Radiator Fan Failure
If you’ve been driving slowly for a while and your car overheats, check your radiator fan. The radiator fan is designed to draw air into the engine when the vehicle isn’t going fast enough. If the radiator fan isn’t working, your car should cool down quickly when you start driving again.
9) Cracked Cylinder Head or Block
Although rare, cracks can occur on the top end (cylinder head) or bottom end (block) of the engine itself. Cracks in the cylinder head or block are a major engine problem and require replacement of the broken parts. This type of problem is very rare and usually only occurs if the engine overheats excessively.
What should I do if my engine overheats?
If your engine is overheating, you can cool it down by following these simple steps:
1) Turn off your air conditioner
Air conditioners generate heat and the hot air from the condenser blows directly through the radiator. This means the radiator is getting most of the hot air to cool the engine, and it may just seem like your car is overheating when the A/C is on.
If your vehicle is equipped with a front intercooler, this is another component that heats the air before it gets to the radiator. Keep this in mind if you are considering aftermarket upgrades for your turbo engine.
2) Turn on the heater
The heater core is basically a small secondary radiator. If your main radiator can’t keep up, consider blowing engine heat into the cabin at full speed.
3) Short switching (Manual switching)
Short switching results in lower speeds. High engine speeds produce more heat than low engine speeds.
4) Check the radiator airflow (symptoms of a bad radiator)
If you have an older car, make sure there is no debris blocking airflow to the radiator. Also check the area between the condenser and the radiator.
The radiator fins are made of thin aluminum and can bend easily when subjected to impact. Over time, many bent radiator fins will affect cooling performance. It is possible to individually smooth out these radiator fins, although the process is quite labor intensive. Some people choose to replace their radiators.
5) Upgrade your cooler
As a last resort, you can try upgrading to a larger cooler. Sometimes, you may need more cooling power, and a larger aftermarket radiator is the best way to achieve this. Consider this option if you have tried all other options and still experience regular heat buildup due to high ambient temperatures.
What not to do
1) Don’t ignore it
If your car starts to overheat, you need to solve the problem as soon as possible. If you are driving at high speed, try to ease off the accelerator. If the temperature continues to rise, stop the car and let it idle for a while to allow the radiator fan to cool the engine under a very light load.
If the temperature continues to rise after these steps, shut off the engine and wait until the car cools down completely.
2) Don’t drive it any further
If your car is overheating, you need to find out the cause and fix the problem. Don’t let your car overheat more than once. Continuous overheating will cause more expensive problems.
For example, a $10 thermostat could result in a $6,000 engine replacement if the block breaks due to pressure buildup.
3) Don’t panic
It’s normal to be a little alarmed when you see the temperature gauge pointing to the hot side. Don’t worry and avoid making any sudden maneuvers that could cause an accident.
In most cases, actual engine failure can be prevented if caught early. Only stop when you know it is safe. It is better to continue driving with a hot engine than to stop in the middle of the highway.
How long does it take for an engine to cool down? It takes time for an engine to cool down. The time varies depending on the ambient temperature and motor overheating temperature.
If you just want the temperature to return to normal operating temperature, waiting 30 minutes is enough. However, it usually takes about 3-5 hours for the engine to completely cool down to ambient temperature.