What are the reasons for the overflow of the expansion tank?
2 Answers
The reasons for the overflow of the expansion tank: 1. When the engine temperature is too high, the coolant will boil and overflow from the expansion tank cap due to excessive pressure. The cause of the high engine temperature should be identified and addressed; 2. The water temperature is too high. During driving, cooling relies on natural wind and the fan. After stopping and turning off the engine, the fan stops working; 3. Blockages in the radiator or hoses, or leaks in the radiator cap or the cap connecting to the engine. The car radiator, also known as the heat exchanger, is a key component in the car's cooling system, functioning to dissipate heat. The radiator is usually located behind the air conditioning condenser. Opening the engine compartment only reveals the upper cover of the radiator. To see the radiator's position, the front bumper cover needs to be removed.
I experienced the coolant reservoir spraying issue just last year. The temperature gauge suddenly spiked, and coolant erupted from the reservoir cap, forcing me to pull over immediately. Later inspection revealed a blown head gasket—the seal between the cylinder and coolant passage had failed. High-temperature, high-pressure gas leaked into the cooling system, causing a drastic pressure surge that forced fluid to eject from the weakest point: the reservoir vent. This issue severely damages engines—shut off immediately and tow! Alternatively, clogged radiator fins, inoperative cooling fans, or a stuck thermostat preventing coolant flow can cause total cooling failure, making boiling coolant erupt from the reservoir. Regularly clean insect debris and pollen buildup in front of the radiator.
