What are the components of antifreeze?
4 Answers
The main components of antifreeze are: 50% purified water, 40% methanol, and 10% other substances. Methods for selecting antifreeze: The basic indicators of antifreeze are the freezing point and boiling point. The freezing points of antifreeze available on the market include -15°C, -25°C, -30°C, -40°C, and other specifications. Generally, it is advisable to choose one that is at least 10°C lower than the lowest temperature in your region. Methods to determine if antifreeze is insufficient: Observe the antifreeze warning light on the dashboard. If it lights up, it is likely due to insufficient antifreeze, though it could also be caused by excessively high temperature inside the cylinder. Check the antifreeze reservoir. If the liquid level is below the minimum mark (MIN), do not continue driving and add antifreeze promptly. Check the water level scale markings on the antifreeze bottle. The normal antifreeze level should be between the maximum and minimum water level marks. Whether antifreeze is insufficient depends on the scale. If the antifreeze level is below the minimum mark, it indicates a shortage of antifreeze.
When maintaining my car, I pay special attention to the composition of the coolant. It is mainly composed of ethylene glycol and purified water, mixed in roughly equal proportions, so it won't freeze even at sub-zero temperatures. The key also lies in various additives, such as corrosion inhibitors to protect the metal parts of the engine from rusting, and buffers to maintain the acid-base balance and prevent corrosion. Scale inhibitors prevent scale buildup from clogging the pipes, and dyes allow different formulations to be distinguished by color. Every time I replace it, I choose reputable brands because inferior products lack sufficient additives, and after just six months of use, the radiator was corroded and leaked. Remember not to mix coolants of different colors, as the additives can react and produce sediment.
From a chemical perspective, the formulation of antifreeze is quite ingenious. The base fluid consists of ethylene glycol or propylene glycol, which alter the freezing and boiling point characteristics of water. The additive system is particularly sophisticated: silicate corrosion inhibitors protect aluminum radiators, nitrates prevent cast iron corrosion, while organic acid formulations offer extended service life at higher costs. Antifoaming agents prevent bubble formation during circulation that could impair heat dissipation, and pH stabilizers maintain the fluid in a weakly alkaline state. Through testing aged antifreeze, I've observed that when buffer agents become depleted, the pH drops into acidic territory, leading to pinhole corrosion in radiators. This underscores the importance of regular fluid replacement - don't wait until additives become ineffective before taking action.
With twenty years of experience in auto repair, I've disassembled over a thousand cooling systems. Antifreeze consists of three core components: ethylene glycol as the base fluid, which is cost-effective and performs well; distilled water, superior to tap water; and the most crucial element—the additive package. Inferior products cut corners by reducing corrosion inhibitors, leading to radiator rust-through in just three to four years. Mixing different formulations can create gel-like substances that clog the radiator's fine tubes—one vehicle suffered engine overheating and cylinder scoring as a result. During maintenance, we always check the freezing point: every 10% decrease in ethylene glycol concentration raises the freezing point by 6 degrees. I recommend owners perform a complete system flush with every two-year coolant change to prevent residual old fluid from corroding the new.
