What Causes a Car's Radiator to Boil Over?

2 Answers
LeReagan
07/24/25 8:08am
There are many reasons that can cause a car's radiator to boil over. Apart from hot weather, overloaded air conditioning operation and faulty cooling components can also lead to this issue. More relevant information is as follows: 1. Conducting a comprehensive inspection of the car's cooling system is the primary method to prevent boiling over. Check whether the cooling fan is working properly, if there are any leaks in the radiator, or if the coolant is insufficient. If the radiator is leaking, it needs to be repaired or replaced promptly. If the coolant level is low, it should be replenished in time. If the coolant appears cloudy or deteriorated, it should be replaced. Additionally, the water content in ordinary coolant can form a vapor barrier layer on the cylinder walls of the engine, hindering heat dissipation, leading to engine failure and shortening the engine's lifespan. 2. A car's radiator boiling over usually refers to the engine (also known as the motor or internal combustion engine. Depending on the type of fuel burned and the ignition method, it can be divided into diesel engines and gasoline engines) reaching a temperature that is excessively high for the normal operating temperature range, thereby affecting the machine's normal operation and causing damage. "Excessively high temperature" often refers to temperatures above 85 degrees Celsius. Different engine models have different standards, and the higher the temperature exceeds the normal range, the greater the damage to the machine.
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VonCorey
08/11/25 3:46am
I've encountered the issue of the radiator boiling over several times. Experience tells me it's often caused by insufficient coolant—it burns dry if not checked in time; or a faulty water pump that stops the water circulation, causing the temperature to skyrocket. If the radiator is clogged, heat can't escape, leading directly to boiling. A stuck thermostat is another common culprit, making the engine heat up extremely fast. Fan failure is especially noticeable in traffic jams, causing the engine to overload immediately. Even worse is a damaged engine head gasket, allowing air bubbles into the cooling system, which expand and cause eruptions. These issues can make the radiator boil over, spewing white smoke—extremely dangerous! I once faced this during a long trip and was so scared I immediately pulled over, turned off the engine, and opened the hood to cool it down. Luckily, no damage was done. I recommend checking coolant levels monthly, performing seasonal maintenance, and cleaning the system to prevent small problems from turning into disasters. If it happens, call a tow truck immediately—don't push your luck, safety comes first.
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