What Causes Coolant to Boil Over?
2 Answers
The reasons for coolant boiling over are: 1. Air in the cooling system occupies space, making it appear that there is sufficient coolant when, in fact, the engine's cooling system is not fully filled with coolant. The trapped air hinders coolant circulation, leading to overheating or even boiling over. 2. A faulty thermostat fails to open when the engine overheats or boils over, preventing the cooling system from entering a full circulation cycle. 3. A malfunctioning water pump results in poor coolant circulation, failing to dissipate heat effectively. 4. A broken water pump belt. 5. Excessive scale buildup inside the radiator, obstructing coolant flow. Additional information: 1. If the engine overheats or boils over, immediately pull over to a safe location, turn off the engine to prevent further temperature rise and more severe damage. 2. The vehicle can be towed for repairs. 3. If the distance is short, you may wait for the engine to cool down and then drive back at a low speed, but closely monitor the temperature gauge.
Having driven for ten years, the most common cause of coolant boiling is cooling system issues. Getting stuck in traffic during summer causes engine temperatures to skyrocket, overwhelming the cooling system. A radiator clogged with dust or bugs, a fan that doesn't spin or spins too slowly, reduces cooling efficiency. If the water pump fails, the antifreeze can't circulate properly, trapping heat inside the engine. A thermostat stuck in the closed position prevents the main cooling cycle from activating, causing water temperature to rise rapidly. Some car owners improperly use coolant or mix it with tap water, lowering the boiling point and leading to overheating. In such cases, immediately pull over, open the hood to dissipate heat, and avoid shutting off the engine right away—wait until the RPM stabilizes before turning it off.
