What causes a car to overheat?

Several problems can cause your car to overheat. Common causes are a leaky cooling system, a clogged radiator, a faulty thermostat, or a faulty water pump.

This is the worst feeling a driver can have: the undeniable fact that something is wrong. Steam escapes from under the hood, and warning bells ring and lights flash on the dashboard. Your engine is too hot and you need to pull over to the nearest parking lot or to the side of the road to let the engine cool down. You have a knot in your stomach - it can be expensive.

Heat is the engine's enemy. The damage caused by overheating can be catastrophic and require an overhaul or replacement if the problem is not corrected in time. There are many conditions that can cause overheating, some requiring simple repairs and others requiring hours of operation and high parts costs.

What is overheating?

The engine works efficiently at a certain temperature. This temperature, although too hot to touch, is significantly lower than without a cooling system. Overheating is when the engine temperature rises to the point where mechanical damage can occur. Usually, a sustained temperature of over 240 degrees Fahrenheit is enough to cause concern. Steam coming from the engine area, a temperature gauge jumping into the red zone, and engine warning lights, often shaped like a thermometer, are signs that your car may be overheating.

Does my car have a cooling system?

Whether big or small, every engine has a cooling system. In the early days of vehicle development, car engines were air-cooled. Essentially, the impact of the air passing over it dissipated the heat of the engine. As engines became more complex and powerful, cases of overheating became more frequent, and a liquid cooling system was developed in response.

Liquid cooling systems are used almost exclusively in modern automotive design and engineering. Your modern car is equipped with a cooling system that circulates coolant (also known as antifreeze) throughout the engine and through the radiator to remove heat.

How does it work?

The engine cooling system consists of many parts. There is a water pump, thermostat, heater core, radiator, coolant hoses and the engine itself. Here's how it works:

• The water pump has an impeller that circulates the coolant. The impeller looks like a fan or windmill and is driven by a V-ribbed belt, toothed belt or chain.

• The coolant flows through the engine's coolant jacket, which is a maze of channels that run through the engine block. The heat is absorbed by the coolant and removed from the engine to the heater core.

• The heater core is a small radiator inside the car, designed to heat the passenger compartment. The valve controls how much hot coolant passes through the heater core to raise the temperature of the air inside. The coolant then travels through the hose to the radiator.

• The radiator is a long tube coiled into shorter coils. The air passing by the coils dissipates heat from the coolant inward, lowering the temperature of the coolant. After passing through the radiator, the hose returns the cooled liquid back to the water pump, and the cycle begins anew.

Why does the engine overheat

There are several reasons for overheating. Almost all of them occur due to lack of circulation, but can be caused in different ways.

• Cooling system leaking - A leak in the cooling system does not directly cause the engine to overheat. The immediate cause is air getting into the cooling system. If there is a leak, the coolant level drops and air is sucked in and circulated. Obviously, air is lighter than the coolant, and when it rises to the top of the cooling system, a so-called airlock occurs. An airlock is a large bubble that the coolant flow cannot force through the cooling system. This means that the cooling system effectively stops circulating and the coolant left inside the engine overheats.

• Locking - Another indirect reason is a blockage in the cooling system, since overheating actually occurs due to the lack of coolant circulation inside the engine. When the cooling system is blocked and the coolant cannot circulate to the radiator to dissipate heat, the engine overheats. Here are some common obstacles:

  • A thermostat that doesn't open when it should.
  • Mineral deposits are blocking the radiator.
  • Foreign object inside the cooling system.

• Faulty water pump - Water pump failure is one of the most common causes of overheating. The water pump is the most active component of the cooling system and is responsible for keeping the coolant circulating. Over time, the bearing or impeller inside the water pump may wear out or break, and the impeller will no longer turn. When this happens, it usually takes a short time for the engine to overheat.

• Coolant not concentrated enough - This condition is primarily of concern in cold climates, when the temperature drops below zero. The coolant can thicken inside the engine or radiator and cause a blockage. Even in cold weather, the engine will easily overheat if the antifreeze thickens and cannot circulate. This can result in internal damage to components that will require attention, such as a possible radiator repair.

A less well-known system to help keep the engine cool is the engine oil itself. It plays a big role in engine cooling as well as preventing excessive temperature rise. Engine oil lubricates the internal parts of the engine, preventing friction, which is the main cause of heat inside the engine.

Many manufacturers build an engine oil cooler into their vehicles that acts as a radiator. The hot oil circulates in the oil cooler where the heat is dissipated before it is returned to the engine. Engine oil provides up to forty percent of engine cooling.

Routine repairs required to correct overheating

• Replacing the water pump
• Repair or replacement of the radiator
• Flushing with antifreeze
• Replacing the thermostat
• Topping up or changing engine oil
• Replacing the coolant hose

How to prevent overheating

There are several ways to deal with car overheating.

• Flush the cooling system at the manufacturer's recommended intervals or when it becomes dirty.
• Have a technician repair coolant leaks as soon as they appear.
• Change engine oil regularly.
• Watch the temperature gauge on the dashboard. If the arrow turns red or the "engine hot" warning light comes on, stop and turn off the vehicle to prevent damage.

Don't risk your car if it starts to overheat. If your car has overheated at least once, then something is wrong and needs to be fixed. Contact an AvtoTachki certified mobile technician to check what is causing it to overheat.