What Causes a Sedan to Leak Antifreeze?
3 Answers
The reasons for a sedan leaking antifreeze are: 1. Loose sealing at the connection between the antifreeze reservoir and the radiator; 2. Aging and cracking of rubber hoses; 3. If the radiator frequently requires water refills and the car is old, the radiator may be rusted through; 4. Use of improper coolant or coolant with too much water content. Automotive antifreeze, also known as antifreeze or non-freezing liquid, is officially called automotive antifreeze coolant, meaning it is a coolant with antifreeze properties. Antifreeze prevents the coolant from freezing and expanding in cold weather, which could crack the radiator or damage the engine block. Antifreeze is not just for winter use; it should be used year-round. In regular car maintenance, the engine antifreeze should be replaced every year, with more frequent replacements for special vehicles.
My car had a coolant leak last year, which was found to be caused by a loose radiator connection. Older cars that have been driven for seven or eight years are most prone to such issues—aging and deformed rubber hoses or cracked seals can lead to leaks. Water pump failure is also a common cause; when the internal seals wear out, it can result in dripping. The radiator itself may leak coolant if it gets hit by a stone or develops small holes due to internal corrosion. Last time, the repair shop also mentioned that sudden temperature drops in winter could freeze and crack the engine block's freeze plugs, causing leaks. The most troublesome issue is a leaking heater core, which requires removing the entire dashboard. Now, I check the coolant level every month and address any abnormalities immediately, as engine overheating can be a costly problem.
With over a decade of experience in automotive mechanics, I've found that coolant leaks typically stem from sealing issues in the cooling system. Radiator cracks are the most common culprit, especially in vehicles over five years old, where aluminum cooling fins are particularly prone to corrosion and leakage. Aging and cracking rubber hoses are widespread, particularly at the clamp positions near connections. The mechanical seal at the water pump is a weak point, with leaks often dripping from the drain hole. Heater cores located behind the dashboard require interior disassembly for repairs when leaking. Rusted-through engine block freeze plugs present a more challenging scenario, necessitating engine disassembly. I recommend identifying the leak location by the fluid color: green usually indicates radiator or hose issues, while coolant mixed with oil foam may point to a head gasket problem.
