CAUSES OF ENGINE OVERHEATING IN CARS

Engine overheating occurs when the amount of heat generated during operation exceeds the cooling capacity of the entire cooling system. This is a dangerous condition that can cause severe engine damage if not addressed in time. Below are the main causes of overheating:

1. Incorrect Technical Intervention in the Engine

• Modifying engine parameters improperly (increasing power, interfering with ECU, using incorrect spark plugs, etc.).

• Incorrect ignition timing or air-fuel ratio (gasoline–air or diesel–air) leads to inefficient combustion, generating excess heat.

• For diesel engines: incorrect fuel injection timing, clogged injectors, incorrect injection pressure.

• Faulty spark plugs/injectors, malfunctioning fuel pumps, inaccurate engine sensors, or loose wiring cause incomplete combustion.

• Unstable vehicle electrical system: overly high or low voltage reduces ignition efficiency and increases heat.

2. Harsh Operating Conditions

• Continuous long-term driving or overloading the vehicle.

• Driving in high-temperature conditions (scorching sun, hot pavement), prolonged uphill climbs, poor roads, dusty areas, or prolonged traffic jams.

• Frequent acceleration and braking or prolonged maximum-speed driving prevent the engine from cooling down.

3. Ineffective Cooling System

Mechanical Failures:

• Cooling fan not working (burned-out electric fan, jammed motor).

• Malfunctioning water pump (damaged impeller, loose or broken belt).

• Stuck thermostat not opening to release heat.

• Leaky, clogged, or broken radiator.

• Clogged cooling pipes due to debris, rust, or scale.

Coolant Issues:

• Low coolant levels or excessively dirty/expired coolant.

• Using the wrong type of coolant (e.g., tap water or mineral-rich spring water causing deposits).

• Coolant containing corrosive substances that damage radiators and pipes.

Poor Maintenance:

• Failure to clean radiators and cooling components regularly allows dirt and mud buildup, reducing heat exchange.

• Neglected maintenance leads to airlocks, deposits, or corrosion inside the cooling system.

4. Inefficient Lubrication System

Lubricating oil accounts for up to 40% of the engine's cooling. Therefore, the following issues can significantly raise engine temperature:

Incorrect Oil Use:

• Using oil with viscosity not matching the engine’s specification (too thick or too thin).

• Using the wrong type of oil (recycled oil, low-quality oil, unknown origin).

• Using oil lacking sufficient cooling, anti-wear, or detergent additives.

Poor Oil Maintenance:

• Underfilling or overfilling engine or transmission oil.

• Not changing oil on schedule; old oil loses lubrication and cooling ability.

• Failure to check oil levels regularly (due to leakage or evaporation).

Transmission Oil Issues:

• Using the wrong oil type (e.g., ATF in manual transmission).

• Low transmission oil levels or failure to change oil on time.

• Using overly thick gear oil increases friction and heat.

5. Exhaust System Problems

Improper exhaust system function may cause heat to build up in the engine:

• Clogged exhaust pipes or catalytic converters.

• Faulty oxygen or emission sensors miscontrol fuel quantity, causing incomplete combustion.

• Stuck EGR valve reduces exhaust-based heat dissipation.

6. Aging Materials and Components

• Blown or leaking head gasket allows coolant to enter combustion chambers, reducing pressure and proper heat transfer.

• Aged gaskets, rubber hoses, valves, or seals cause oil/coolant leakage.

• Malfunctioning temperature, pressure, or flow sensors prevent ECU from adjusting cooling correctly.

Conclusion:

Engine overheating results from a combination of causes—not only from the cooling system but also from lubrication, fuel system, driving conditions, electrical system, exhaust, and human intervention.

To prevent overheating:

• Always perform regular maintenance as recommended by the manufacturer.

• Frequently check oil and coolant levels.

• Avoid unauthorized modifications if not technically proficient.

• Use the correct types of lubricants and coolant; replace them on time.

• If the vehicle shows abnormal heat signs, stop and inspect immediately—do not continue driving to avoid severe damage.