What Causes an Engine to Overheat in a Car?

An engine overheating is a serious problem that can cause major damage to your car. If you notice that your car is overheating, pull over to the side of the road as soon as possible and turn off the engine. Let the car cool down before attempting to restart it.

What are the symptoms of an overheating engine?

The temperature gauge is in the red zone.
Steam or coolant is leaking from the engine.
The engine is knocking or pinging.
The car is losing power.
The exhaust is smoking.

What causes an engine to overheat?

There are a number of things that can cause an engine to overheat, including:

Coolant Problems

Coolant is a fluid that helps to keep the engine cool. If the coolant level is low, or if the coolant is old or contaminated, it can cause the engine to overheat.

To check the coolant level, open the hood and look for the coolant reservoir. The reservoir is usually located near the front of the engine. The coolant level should be between the “min” and “max” marks on the reservoir.

If the coolant level is low, add more coolant to the reservoir. Be sure to use the type of coolant that is specified in your car’s owner’s manual.

If the coolant is old or contaminated, it should be flushed and replaced. A coolant flush is a simple procedure that can be performed at most auto repair shops.

Water Pump Problems

The water pump is a pump that circulates coolant through the engine. If the water pump fails, it can cause the engine to overheat.

Symptoms of a failing water pump include:

A leak in the water pump housing.
A whining or grinding noise coming from the water pump.
The car is overheating.

If you suspect that the water pump is failing, have it inspected by a mechanic as soon as possible.

Radiator Problems

The radiator is a heat exchanger that helps to cool the coolant. If the radiator is clogged or damaged, it can cause the engine to overheat.

Symptoms of a clogged or damaged radiator include:

The car is overheating.
The radiator is leaking coolant.
The radiator fins are bent or damaged.

If you suspect that the radiator is clogged or damaged, have it inspected by a mechanic as soon as possible.

Thermostat Problems

The thermostat is a valve that regulates the flow of coolant through the engine. If the thermostat fails, it can cause the engine to overheat.

Symptoms of a failing thermostat include:

The car is overheating.
The temperature gauge is fluctuating.
The engine is running rough.

If you suspect that the thermostat is failing, have it inspected by a mechanic as soon as possible.

Head Gasket Problems

The head gasket is a seal between the engine block and the cylinder head. If the head gasket fails, it can cause coolant to leak into the cylinders. This can cause the engine to overheat.

Symptoms of a failing head gasket include:

The car is overheating.
The coolant level is low.
The exhaust is smoking.
The engine is running rough.

If you suspect that the head gasket is failing, have it inspected by a mechanic as soon as possible.

How to prevent an engine from overheating

There are a number of things you can do to prevent your engine from overheating, including:

Check the coolant level regularly.
Flush and replace the coolant every 2-3 years.
Inspect the water pump, radiator, and thermostat regularly for signs of wear or damage.
Replace the water pump, radiator, or thermostat if they are failing.
Drive your car in a way that minimizes the risk of overheating. For example, avoid driving in stop-and-go traffic, and don’t tow heavy loads.

What to do if your engine overheats

If your engine overheats, pull over to the side of the road as soon as possible and turn off the engine. Let the car cool down before attempting to restart it.

Once the car has cooled down, check the coolant level. If the coolant level is low, add more coolant to the reservoir. Be sure to use the type of coolant that is specified in your car’s owner’s manual.

If the coolant level is not low, there may be a more serious problem that is causing the engine to overheat. In this case, you should have the car towed to a mechanic for diagnosis and repair.