What Causes Antifreeze to Easily Overheat?
4 Answers
Reasons why antifreeze easily overheats: 1. The radiator stops working, causing the water temperature to become too high; 2. The antifreeze does not circulate, the thermostat does not open, the water pump fails to operate normally, resulting in blockage of the water circulation pipeline and causing overheating; 3. Insufficient antifreeze or poor-quality antifreeze with a low boiling point, making it prone to overheating. Antifreeze can help raise the boiling point, prevent scale and rust formation, improve heat dissipation, lubricate the water pump, and avoid or eliminate engine damage caused by instant high temperatures due to bubbles. When antifreeze is low, try not to add water to make up for it, especially in summer. This is because the chlorine content in tap water can cause corrosion, rust, and blockage in the radiator, engine, and other systems, leading to poor cooling system performance and engine overheating, which can damage the vehicle.
I've encountered this issue several times. Coolant boiling is usually a sign of a cooling system problem. The most common cause is a clogged radiator - when too much debris like willow catkins or insects blocks the airflow. A broken fan is also dangerous, especially during summer traffic jams when overheating occurs easily. If the water pump fails and coolant stops circulating, it will definitely boil. A thermostat stuck in the closed position can also damage the engine. The coolant itself shouldn't be used for too long - it needs replacement every two years, as its boiling point decreases over time. Also, always check if the coolant reservoir is leaking. If boiling occurs, immediately turn off the engine and wait for it to cool - otherwise you risk blowing the head gasket!
Last year my car kept overheating on mountain roads, and a thorough inspection revealed the issues. Deteriorated coolant is the most common culprit, as increased impurities reduce heat absorption and corrode the water channels. Leaking radiator hoses from aging can be disastrous, and insufficient antifreeze inevitably leads to overheating. If the water pump impeller gets corroded and can't rotate, coolant gets trapped in the engine. A weakened radiator cap spring lowers pressure, dropping the boiling point by over 10°C. For modified cars, check if the electric fan has sufficient power—stock fans can't handle larger radiators without upgrades. Remember: never open the cap immediately after overheating—high-pressure steam can cause severe burns!
Coolant boiling is essentially a cooling system failure. A faulty fan clutch is the most troublesome, as the blades spin idly at high speeds without providing cooling. Internal radiator blockages are more concealed than external ones; radiators filled with tap water usually develop scale. A blown cylinder head gasket allows exhaust gases to enter the coolant passages, causing water vapor to emit from the exhaust pipe. Mixing different types of antifreeze can trigger chemical reactions that produce sediment, clogging the pipes. While a tire shop overinflating your tires may just waste fuel, a repair shop diluting antifreeze with tap water can literally be deadly!
