What is the difference between windshield washer fluid, coolant, and tap water besides color?
Searching for car accessories online reveals a dazzling array of products, with all kinds of items available. Regarding car care and maintenance, there are various colored liquids, such as windshield washer fluid, coolant, and all sorts of cleaners, which come in vibrant hues—red, green, blue, purple, you name it. Sometimes, looking at these attractively packaged bottles and cans can be incredibly tempting and stir up a strong urge to buy.
Why are these windshield washer fluids and coolants made in such different colors? What exactly makes them different from ordinary water? And when we're running low on windshield washer fluid or coolant, can we simply top them up with water? Today, let's talk about this topic.
1
Coolant (Radiator Fluid)
Coolant, also known as radiator fluid, is used to cool down the engine. During engine operation, the coolant continuously circulates through the radiator and pipes, flowing through the engine to absorb its heat. The heated coolant then moves to the intercooler section, where it is cooled by the airflow generated while the vehicle is in motion, before re-entering the engine to dissipate more heat. The temperature gauge commonly seen on the vehicle dashboard refers to the temperature of the coolant.
Coolant is a mixture of water, antifreeze, dyes, and various additives, primarily categorized into conventional coolant and waterless coolant. Based on the type of antifreeze it contains, coolant can also be classified into alcohol-based, glycerol-based, ethylene glycol-based, and other types. Besides dissipating engine heat to achieve cooling effects, coolant must fulfill several other functions. Firstly, it should not boil under high temperatures and must remain in liquid form without freezing in low-temperature conditions. Secondly, after contact with the cooling circulation system, it should not produce scale or rust. Lastly, coolant must also prevent corrosion within the cooling pipelines.
As we all know, for ordinary water, the boiling point is 100°C, and the freezing point is 0°C. Since regular water does not meet the standards for coolant, if it freezes at low temperatures, it can block the cooling pipes, and the expansion upon freezing can rupture the rubber hoses. Therefore, generally, the freezing and boiling points of coolant are below -38°C and above 108°C, respectively. There can be significant variations in freezing and boiling points among different types and brands of coolant, allowing consumers to choose based on the lowest and highest temperatures in their region. For example, southern regions may opt for products with higher boiling points, while northern regions can select those with lower freezing points.
Since the coolant is continuously heated by the engine, evaporation occurs after some time of use. Therefore, you may notice that the coolant level is below the normal mark after a few years of driving a new car. If the coolant loss is not too significant or in emergency situations, such as a coolant line leak, you can add an appropriate amount of water to replenish or for temporary use. However, it is crucial to note that only purified or distilled water should be added. Never use mineral water or tap water, as they contain minerals and impurities that can cause scale or rust buildup in the radiator, thereby damaging the internal pipeline environment.
2
Windshield washer fluid (wiper fluid)
Before each car wash, the car wash shop will first open the hood to fill up your windshield washer fluid reservoir. Some people might wonder: is it okay to add tap water to the windshield washer fluid? In fact, adding tap water to the windshield washer fluid is not a problem, but using dedicated windshield washer fluid might yield better results. This is because the car's windshield often accumulates various stains, such as dust, dirt, exhaust fumes, grease, bird droppings, tree sap, and so on. Over time, these can lead to hard-to-clean contaminants and oil films on the windshield.
Many experienced drivers and car owners encounter this issue: on rainy days, the windshield becomes blurry, and turning on the wipers only makes it worse. A significant reason for this is the presence of an oily film or other stubborn stains on the glass. Additionally, the rubber blades of the wipers may have aged and hardened, preventing them from properly conforming to the curvature of the windshield. As a result, the more you wipe in the rain, the blurrier it gets, severely compromising driving safety.
Specialized windshield washer fluid or concentrated wiper solution offers superior cleaning performance compared to plain water, effectively removing oil stains and various marks from the glass. Some washer fluids also contain water-repellent agents, which not only clean the windshield better with each spray and wipe but also leave behind a hydrophobic coating. This ensures that during rainy weather, water on the glass doesn't pool but instead beads up and rolls off or is blown away by the wind while driving, significantly improving visibility and safety for drivers in wet conditions.
These coolants and windshield washer fluids are dyed with various bright pigments precisely to make it clear during daily use that these products are not meant for consumption, thereby enhancing their safety. If these products were made colorless and odorless, the risk of accidental ingestion would significantly increase. Additionally, formulating them in vibrant colors serves to align with and enrich packaging aesthetics, product identification, and other informational aspects.