There are a number of problems that might cause a car to overheat. Many of them are easy to fix, while others are a bit more complicated. If, for any reason, a car overheats, it should be stopped and given time to cool down. If it is allowed to run while it is hot, this could ruin the engine. Never continue to run an overheated car!
Bad radiator cap
One of the easiest overheating problems to fix on a car is the radiator cap. Sometimes the cap does not get put back on tight, or it becomes loose. The solution is to simply screw it back on tight. Over time the cap may deteriorate. If this happens, the cap should be replaced. Radiator caps are available at local auto parts stores. They do not cost much and are easy to put on.
If a radiator cap goes bad repeatedly, it is a good idea to check the radiator to see if it is clogged. It can become clogged after the car has been driven over 50,000 miles. Clogged radiators can be prevented by having the radiator flushed once a year. Sometimes a radiator simply wears out from age. When this happens, the whole radiator should be replaced.
Another common problem that causes a car to overheat is low coolant. To see if this is the problem, check the water overflow reservoir. If it is low, try filling it up with equal amounts of water and anti-freeze. If it is empty, the radiator is probably empty or nearly empty as well. A 50/50 mixture of water and antifreeze can be used to fill the radiator. After refilling it, keep an eye on the water reservoir. If the level keeps getting too low, there may be another problem, such as a bad radiator hose or bad water pump.
Bad radiator hose
Sometimes the radiator hoses become old and brittle. They can spring leaks or get slits in them and this causes the water level to become low. A car cannot run without sufficient water and coolant, so this will make the car overheat. The solution to this problem is to replace the radiator hose. This should be an easy and inexpensive fix.
One thing to check if the car overheats is the thermostat. If it has gone bad, the car may lose water quickly. Even if it does not lose water, the car may overheat. Stop the car and allow it to cool down. After it is cool, it can be started again and driven carefully to the shop or garage. It should not be driven anywhere else until it is fixed. Thermostats are not expensive and should be easy to replace. Once the new thermostat is in and the water and coolant are filled up again, the car should run as good as new.
Bad fan belt or cooling fan
Engines are cooled either by an electric cooling fan or a fan powered by a fan belt. When the cooling fan or fan belt goes bad, the car will overheat while idling because there is no air blowing on the engine to cool it. The solution to this problem would be to replace the cooling fan or fan belt.
Bad water pump
Water pumps are very important. They circulate water through the engine and radiator, cooling the engine by removing the heat it produces when it runs. If the coolant is low or the overflow reservoir boils or empties frequently, a bad water pump is something to suspect. Eventually the water pump will fail, and the engine will overheat. Sometimes a car will not run if the water pump goes bad. This protects the engine from being damaged by overheating. In order to resolve this problem, the water pump must be replaced.
Anything that causes a car to overheat should be taken seriously. Even though the problem may be easy to fix, a car cannot be driven without water or a fan to cool the engine. If a car is allowed to run while it is overheated, the engine may be ruined. The only solution to that would be to rebuild the engine or purchase a new car. Even in the case of an overheated car, the old adage proves true, “An ounce of prevention is worth a pound of cure.” Do not wait to fix a car that is overheating. A little money spent now will save a lot of money later.