What Does It Mean When Antifreeze Boils Over?
3 Answers
Antifreeze boiling over refers to a situation where, during vehicle operation, the engine's high temperature causes the antifreeze temperature to rise to the boiling point, resulting in overflow. When the boiling antifreeze comes into contact with hot metal parts, white smoke is produced. The causes include: 1. The radiator stops functioning, leading to excessively high water temperature; 2. Antifreeze circulation failure due to a thermostat not opening, water pump malfunction, or blockage in the water circulation system; 3. Insufficient antifreeze or poor-quality antifreeze with a low boiling point, making it prone to boiling over. Automotive antifreeze, also known as coolant with antifreeze properties, is designed to allow the vehicle to operate in winter's low temperatures. Engine coolant contains substances that lower the freezing point of water, acting as antifreeze agents to prevent the cooling system from freezing in cold weather.
That day I was on a long-distance drive when suddenly the coolant temperature warning light on the dashboard came on, and white smoke started billowing from under the hood, which gave me quite a scare. After stopping and opening the hood, I found that the coolant had sprayed all over the overflow tank. Later, the mechanic told me that the radiator fins were completely clogged with willow catkins, so no matter how fast the fan spun, it couldn’t dissipate heat, causing the coolant to boil over. Now every spring, I remind myself to clean the radiator fins behind the front grille, especially after highway drives when they’re covered in bugs. If I notice the temperature gauge running high, it’s best to find a safe place to pull over immediately—otherwise, continuing to drive could blow the head gasket, and that’s definitely not a cheap fix.
Last time my friend was driving uphill, the coolant boiled over. When I checked for him, I found the thermostat was stuck. This component normally controls the coolant flow through the large circulation loop for cooling, but due to long-term neglect of coolant replacement, scale buildup caused it to fail. With the coolant only circulating within the engine, the temperature naturally skyrocketed until it boiled. This is the worst scenario in summer, so I recommend changing the coolant every two years. If you notice the coolant level in the overflow tank rising abnormally or the cooling hoses feeling excessively hot to the touch, there's a high chance the cooling system has issues. Remember to wait at least half an hour after turning off the engine before opening the overflow tank - steam burns are no joke.
