What are the components of coolant?

[SanPaul]

Coolant is composed of water, antifreeze, and additives. Depending on the components, it can be classified into alcohol-based, glycerol-based, ethylene glycol-based, and other types of coolants. The full name of coolant is antifreeze coolant, which is a coolant with antifreeze function. It can prevent the coolant from freezing and cracking the radiator or damaging the engine cylinder block when the car is parked in cold seasons. Antifreeze is not only used in winter but should be used all year round. In normal car maintenance, the engine antifreeze should be replaced every year. Currently, almost all coolants used in engines domestically and internationally, as well as those available in the market, are ethylene glycol-based coolants.

[NorahLynn]

I always carefully check the ingredient list before changing the coolant for my car. The basic components of common coolant are approximately 50% ethylene glycol and 45% deionized water, with the remaining being key additives—corrosion inhibitors like silicates and phosphates, specifically designed to prevent rust and corrosion on engine metals; antifoaming agents to avoid bubble formation in the pipes which could affect heat dissipation; and pH buffers to maintain stable acidity levels. Some newer coolants use propylene glycol instead of ethylene glycol, which is less toxic and more environmentally friendly. The color differences mainly depend on the dyes used, such as green with chromates and red with organic acid technology additives. Remember that the effectiveness of the components degrades over time, and it's generally recommended to change the coolant every two years; otherwise, the radiator may accumulate scale. Friends in northern regions should opt for formulas with higher ethylene glycol concentration for better antifreeze performance.

[VanMackenzie]

With over a decade of experience in auto repair, I've worked extensively with coolant. Its core composition is essentially ethylene glycol mixed with distilled water, where the ratio determines the freezing point. The additives are the essence—phosphates prevent corrosion in aluminum radiators, silicates protect iron components, and nitrates guard against cylinder gasket erosion. Nowadays, organic acid-based coolants are quite popular, offering more eco-friendly ingredients and longer service life. The main difference between colors lies in their formulations: traditional green contains inorganic salts, while red contains organic acid salts. Mixing coolants with different compositions can cause chemical reactions, ranging from reduced effectiveness to clogged pipes. It's advisable to choose reputable brand products that meet the G48 standard and avoid cheap, off-brand options.

[SanEliza]

The composition of coolant is actually quite particular. The main component is a solution of ethylene glycol and deionized water, with the mixing ratio determining the antifreeze capability. The key lies in the additive package: corrosion inhibitors like borates protect copper fittings, nitrites prevent steel rust; silicates can repair microscopic pores on metal surfaces; defoamers contain silicone compounds; pH stabilizers commonly use benzoates. Nowadays, phosphate-free formulations are more popular to avoid scale buildup in pipes. Interestingly, colors are just dye effects - red or blue doesn't indicate performance differences. Remember to check for ASTM D3306 certification on the packaging, which verifies the composition meets standards.

[StFernando]

I didn't understand coolant composition either until my radiator had issues. It's over 90% a mixture of ethylene glycol and purified water, with additives making up just a few percentage points but playing crucial roles—anti-corrosion elements form protective films on metal surfaces, defoamers ensure smooth circulation, and pH regulators stabilize acidity. Different vehicles have different requirements: older cars suit silicate-based anti-corrosion formulas, while new vehicles benefit from longer-lasting organic acid formulations. Pay attention to ethylene glycol concentration's impact on freeze protection—a 60% concentration is needed for -25°C environments. When deteriorated, the fluid turns cloudy, indicating depleted corrosion inhibitors, suggesting prompt replacement is advisable.