Why does the antifreeze in the water tank turn yellow? Can the antifreeze in the auxiliary water tank be filled up?

Antifreeze is added to the water tank to prevent the engine cylinder from freezing in winter. It can be used in all seasons. Antifreeze also has different colors. After using it for a period of time, you may find that the antifreeze turns yellow. So what is the reason? Is it normal?

Why does the antifreeze in the water tank turn yellow?

The main reason why car antifreeze turns yellow is chemical reaction. The second reason may be due to water rust caused by excessive use or improper use. Whether it needs to be replaced is not based on color but on time.

The main components of antifreeze are ethylene glycol and water, of which ethylene glycol is the main cause of the yellowing color. Ethylene glycol has a low molecular weight and active properties, and can react with lipidation, etherification, oxidation, dehydration, etc. At high temperatures, disodium ethylene glycol should be the reason for the overall yellowing of the color.

No matter what the reason is, it is important to understand that this yellowing is normal. Some cars will change color even if they have only been replaced for three or two days.

The other yellow color is caused by the antifreeze being used for too long, and its anti-rust and anti-corrosion capabilities have been significantly reduced, resulting in rust in the pipes and the emergence of calcium through chemical reactions, which can also change color and even clog the pipes.

Therefore, it is necessary to replace the antifreeze regularly, and the recommended replacement time is every three years.

Can the auxiliary water tank antifreeze be filled up?

If the auxiliary water tank is overfilled when adding antifreeze, then when the vehicle reaches normal water temperature, the antifreeze may overflow. This is because after the engine water temperature rises, the coolant will expand, and the expanded antifreeze will flow to the auxiliary water tank. If the auxiliary water tank is already full at this time, the expanded antifreeze will flow out of the auxiliary water tank.

The water replenishing kettle has a scale, and max represents the upper line. Just add water to the upper line. Generally, the main water kettle will be deficient in water only when it is filled with water from the water replenishing kettle. As long as there is no leakage, there will be no water shortage.

Is it normal for the antifreeze to decrease?

Antifreeze needs to be added regularly during the use of the car. A reduction in the total amount is normal and not a malfunction. The reason why replacement is recommended is that the reduced part is not a synchronous reduction in the total amount, but is limited to the evaporation of water.

The ethylene glycol and water in the antifreeze can achieve a very high boiling point and an extremely low freezing point after being mixed, but the antifreeze containing ethylene glycol is continuously added after the water evaporates, and then evaporates again and added again; too many times of adding will cause the proportion of ethylene glycol to be too high and increase the freezing point, and the antifreeze ability in winter will be significantly reduced; secondly, the flash point of ethylene glycol is very low, and there is a potential risk if the water tank is not sealed tightly or if it is a supercharger.