What are the effects of overfilling car coolant?
3 Answers
After overfilling the coolant, it may cause excessive pressure in the coolant expansion tank. The introduction of car coolant and precautions when filling are as follows: Introduction: The full name should be antifreeze coolant, meaning coolant with antifreeze function. Coolant consists of three parts: water, antifreeze, and additives. According to different antifreeze components, it can be divided into alcohol type, glycerol type, ethylene glycol type and other types of coolant. Precautions: Do not rashly open the cap when the radiator "boils over". Do not spill water on the engine when adding water. The human body should not come into contact with antifreeze. Different types of antifreeze should not be mixed. Do not operate with insufficient water. After the water inlet shows full, start the engine and run it. When the engine temperature rises to the thermostat opening and the air in the water jacket is discharged, the water level will drop. At this time, the radiator can be filled up again.
I've been driving for over thirty years and have encountered issues from overfilling coolant a few times. The most common problem is when the engine heats up, the coolant expands, and the excess liquid overflows from the expansion tank's cap, spilling everywhere. Not only is this a waste of money spent on coolant, but it can also drip onto surrounding engine components. Some coolants are highly corrosive and, over time, can damage wiring or rubber hoses, even causing short circuits or small fires. Once, my neighbor's car triggered an overheating alarm because of this. Every time I add coolant to my car, I always check the expansion tank level after the engine has completely cooled down, keeping it between the min and max marks. If I accidentally overfill, I use a small hose to remove some while the engine is cold to avoid excessive pressure affecting safe driving. Regular maintenance is truly a good habit that saves both hassle and money.
When I first bought my car, I was inexperienced and accidentally added an extra large cup of coolant during a routine maintenance. Shortly after driving, I noticed a pungent smell. Upon stopping, I found the expansion tank area completely wet with significant leakage. After checking some references, I learned that coolant can overflow due to thermal expansion. This not only wasted money on coolant but also risked causing erratic engine temperatures, which over time could lead to unstable system pressure and component damage. Now I've learned my lesson—I check the fluid level monthly. When the engine is cold, I open the tank lid to check the indicator line, ensuring it's ideally filled to the midpoint. If overfilled, I carefully drain the excess into a clean container. This simple precaution helps avoid bigger issues. Detecting problems early saves a trip to the repair shop and hours of hassle.
