Why Does Antifreeze Decrease on Its Own?
3 Answers
It is normal for antifreeze to experience minor depletion. Although the entire cooling system is sealed, the coolant reservoir cap has a pressure relief hole. When internal pressure reaches a certain level, antifreeze will leak from the pressure relief port. Methods to determine if antifreeze is low: Observe the antifreeze warning light on the dashboard. If it lights up, it is likely due to low antifreeze levels, though it could also be caused by excessively high cylinder temperatures. Check the antifreeze reservoir. If the fluid level is below the minimum mark (MIN), do not continue driving and promptly add antifreeze. Inspect the water level markings on the antifreeze reservoir. Normal antifreeze levels should be between the maximum and minimum marks. To determine if antifreeze is low, check the markings—if the level is below the minimum mark, it indicates a shortage. How to choose antifreeze: The basic indicators for antifreeze are its freezing and boiling points. Market options include antifreeze with freezing points of -15°C, -25°C, -30°C, -40°C, etc. Generally, it is advisable to choose an antifreeze with a freezing point at least 10°C lower than the lowest temperature in your region.
The decrease in antifreeze level could be caused by several common issues. As someone who frequently repairs cars, I've found the most likely cause is leakage – aging radiators or loose hose connections can both lead to fluid loss. Some evaporation is normal in high-temperature environments, but excessive reduction may indicate internal leaks, such as damaged cylinder head gaskets allowing coolant to enter the combustion chamber and burn off. During inspection, check for wet spots under the chassis, sniff for a sweet odor, or simply conduct a pressure test to locate leaks. Don't underestimate these minor issues – they can gradually compromise engine longevity. That's why I recommend visiting a repair shop promptly upon noticing abnormalities, rather than waiting until smoke appears, by which point repair costs would be significantly higher.
After driving for a few years, you'll understand that it's not unusual for the coolant level to drop occasionally, especially during hot summers or after long-distance trips. Evaporation is a natural process, but if it decreases too rapidly, you should suspect a possible leak—perhaps the radiator cap isn't tightened properly or there's a tiny crack in a hose. I've made it a habit to check the coolant level regularly, about once a month, ensuring it stays between the min and max marks. If it drops below the minimum line, I carefully inspect the ground for any green liquid traces and try tightening the cap. However, don't hastily top it up with water; always use a proper coolant mixture. Timely maintenance can save a lot of trouble—safety comes first, after all.
