Summer is just around the corner, and temperatures are about to soar. While hot weather can put additional strain on your car’s cooling system, the engine can overheat during any season – including the middle of winter.
Whenever overheating occurs, you run the risk of damaging both the cooling system and the engine itself. Overheating is a big-time problem that you’ll want to address right away.
The 7 Most Common Reasons for Engine Overheating
Engine overheating can happen for many different reasons. Here are some of the most common.
1. Stuck Closed Thermostat
Much like the thermostat in your home, an engine thermostat helps regulate temperature. When the engine is cold, the thermostat remains closed, thereby preventing coolant from moving from the engine to the radiator.
Once the engine warms up, the thermostat opens to allow coolant to flow into the radiator. The radiator acts as a heat exchanger, transferring warmth from the coolant to the outside air. It’s this process that helps keep the engine operating temperature within a certain range.
Problems occur when the thermostat sticks in the closed position. As a result, coolant cannot travel to the radiator. Such a scenario can quickly lead to engine overheating.
2. Faulty Water Pump
Your car’s water pump is driven off the engine by either an accessory belt, timing belt, or timing chain. The water pump housing contains a rotating component called an impeller, which has fan-like blades.
Anytime the engine is running, the impeller is spinning and pushing coolant through the cooling system. If the water pump or its drive mechanism (belt or chain) fail, the coolant will no longer be circulating properly. And that can lead to engine overheating.
3. A Restricted Radiator
To do its job and dissipate heat, the radiator must be free from both internal and external obstruction. Internal blockage can inhibit coolant flow through the radiator, while an external obstruction can prevent airflow across the device. Both issues can lead to engine overheating.
4. External Coolant Leaks
Your car can develop coolant leaks from a countless number of locations. Examples include hoses, the water pump, the radiator, thermostat housing and various parts of the engine. Substantial coolant leaks can lead to a loss of coolant and subsequent engine overheating.
5. Internal Coolant Leaks
Coolant leaks can also develop inside the engine. Usually, the cause is either a damaged head gasket, cracked cylinder head, or cracked engine block. Such issues can lead to cross-contamination between the oil and coolant passengers inside the engine, leading to fluid intermix. Also, the coolant may enter the engine’s combustion chamber(s), where it is burned and consumed. The end result is a low coolant level and engine overheating.
It’s worth noting that, in many cases, internal coolant leaks stem from an overheating problem that began elsewhere. For example, a leaking hose can lead to a low coolant level, resulting in engine overheating and a blown head gasket.
6. Faulty Cooling Fan
When your car is traveling down the road, airflow through the radiator reduces the temperature of the coolant and, therefore, the temperature of the engine. But at idle and under other select conditions, a cooling fan is necessary to keep things cool. As you can probably guess, the engine will overheat when the cooling fan fails.
7. Failed Engine Coolant Temperature Sensor
On modern cars, an onboard computer controls cooling fan operation. To determine when to turn on the fan, the computer relies primarily on data from the engine coolant temperature. Should the sensor fail, the computer might not operate the fan properly, leading to engine overheating.
What to Do if Your Car Begins to Overheat
As we mentioned, overheating can quickly lead to costly engine repairs. If you see the temperature gauge start to climb beyond its normal limit – pull over and shut the engine off immediately. Then call a tow truck and have your car delivered to your repair destination of choice. A professional mechanic will be able to fix the problem and get you back on the road.