Why Does the Car's Antifreeze Keep Decreasing in Summer?
3 Answers
Summer car antifreeze keeps decreasing because the high temperatures in summer cause the antifreeze to expand in volume and leak more easily. Here are the relevant explanations: 1. Main functions: Antifreeze and cooling. One characteristic of antifreeze is its very high boiling point and very low freezing point. This makes it ideal for use in a car's engine. In summer, it primarily serves to cool the engine, while in winter, it mainly prevents freezing. 2. Reasons for decrease: First scenario: Within a normal mileage range, the antifreeze decreases by a small amount. In this case, the reduction is normal. Since the antifreeze is in contact with the engine, when the engine operates, it generates extremely high temperatures, which also raise the antifreeze's temperature, sometimes even causing it to vaporize. Generally, when a liquid's temperature rises or it vaporizes, its volume expands. If this happens in a confined space, the pressure increases. At this point, a pressure relief hole in the antifreeze cap opens, allowing some antifreeze to escape, maintaining appropriate pressure before the hole closes again. In this situation, there's no need to worry. Normal driving is unaffected. Second scenario: The antifreeze decreases very rapidly. Typically, antifreeze decreases faster in summer due to the naturally high temperatures, which make the antifreeze more prone to expansion and leakage. If the antifreeze is found to be decreasing quickly in winter as well, it's advisable to visit a professional 4S shop for inspection. There might be damage to related components causing the antifreeze to leak. If the antifreeze leakage is noticeably fast in summer, it's also a cause for concern. Similarly, an inspection is necessary to identify and address the issue.
Last year my car had the same issue - constantly losing coolant in the summer heat, which was really frustrating. Eventually I figured out the heat was accelerating leakage problems. On older cars, rubber hoses tend to harden and crack. When I crawled under the car, I noticed persistent wet stains around the engine bay hose connections. There's also a more hidden issue - the water pump seal ring fails under high temperatures, causing drips that aren't visible on the underbody cover. Additionally, the expansion tank cap's rubber ring degrades and can't maintain pressure, doubling the evaporation rate. The most serious problem was a slightly blown head gasket, allowing coolant to leak into the combustion chamber - you could even see white smoke from the exhaust. I recommend checking for coolant leaks when the engine is cold, especially around the water pump and hose connections. Address these issues early to avoid overheating and cylinder scoring.
With over ten years of repair experience, abnormal coolant loss in summer can be categorized into three main types: leakage is the most common. Corrosion holes in the radiator or leaks at the heater hose joints can be detected through pressure testing. Internal engine issues, such as a failed cylinder head gasket seal, allow coolant to enter the combustion chamber, resulting in white smoke from the exhaust pipe and emulsified oil visible on the dipstick. Pseudo-consumption is mainly caused by a stuck pressure relief valve in the expansion tank cap or excessive pressure in the cooling system leading to fluid overflow. A newer issue involves design flaws in certain vehicles where high temperatures cause plastic components to deform, resulting in slow leaks. It is recommended that car owners check the coolant level every two days, with fluorescent dye being the most reliable method for detecting leaks. Avoid blindly adding different types of coolant, as this can cause sediment buildup and blockages.
