What are the reasons for a car overheating?

[Alexander]

Here are the reasons for a car overheating: 1. Reason one: Insufficient engine coolant. 2. Reason two: Water pump failure, drive belt wear or looseness. 3. Reason three: The thermostat main valve cannot open or opens too late. 4. Reason four: The shutters cannot fully open. Dirty, damaged radiator fins or clogged radiator cooling tubes. 5. Reason five: Scale buildup in the water jacket and distribution pipes. Below is additional related information: 1. During operation: If the engine suddenly overheats while the car is running, it may be due to a broken fan drive belt, the water pump shaft and impeller disengaging, a leak in the cooling system (such as aging or ruptured hoses), or the thermostat main valve falling off. 2. Recommendation: There are many general reasons for engine overheating, and it is recommended that car owners take their vehicle to a repair shop for inspection and maintenance. Regardless of the cause, overheating can affect driving safety.

[DiAlexa]

Recently, I've repaired several cars with overheating issues. The most common problems are insufficient coolant or leaks, where aging radiator hoses can easily drip. Another frequent issue is the cooling fan not working, especially in summer when the relay or motor of an electric fan fails. If the water pump is broken and the coolant doesn't circulate, the dashboard temperature gauge will spike. A stuck thermostat preventing the main cooling cycle from opening is also dangerous—last year, one car even had its engine seize due to this. Radiators clogged with poplar or willow fluff are quite common too. If the belt breaks, the entire cooling system shuts down. If you notice the engine temperature rising, don't push it—pull over immediately, wait about ten minutes, and then carefully open the hood to inspect. Regularly checking the coolant level and fan operation every 5,000 kilometers can prevent these issues, keeping your car healthy and giving you peace of mind while driving.

[DelLola]

Last year during my road trip, I encountered a high-temperature warning, which turned out to be caused by a stuck thermostat. Actually, there are only a few common reasons for overheating: coolant system leaks, fan malfunctions, water pump failure, or a broken belt. Internal rust blockage in the radiator or external dirt buildup affecting heat dissipation is particularly common in dusty areas. If the coolant hasn’t been replaced for a long time, the boiling point drops, making it prone to overheating. In case of overheating, immediately turn off the A/C and switch on the heater to dissipate heat. After stopping, never rush to open the radiator cap—high-temperature steam can spray out and cause injuries. It’s essential to keep two bottles of distilled water in the spare tire compartment for emergency top-ups. After returning, the mechanic performed a pressure test to identify the thermostat issue. Now, I always pay attention to these key components during every maintenance check.

[DelJosiah]

High engine temperature is usually caused by a failure in the cooling system. The most common issue is insufficient coolant, often due to leaking hoses or cracks in the radiator. If the fan isn't spinning, it might be a faulty relay or blown fuse. A malfunctioning water pump that stops coolant circulation is particularly dangerous. A thermostat stuck in the closed position can block the main coolant circuit. Severe clogging of the radiator with dust and debris significantly reduces cooling efficiency. The engine is also prone to overheating under heavy loads like towing or climbing hills. If the temperature warning light comes on, pull over immediately, turn off the engine, and wait for the temperature to drop before checking coolant levels and radiator surface condition. To check the fan, start the vehicle and turn on the AC to see if the electric fan activates normally. Remember to rinse the radiator grille during regular car washes, and request thermostat opening/closing temperature tests during maintenance.