Car coolant, also known as antifreeze, is primarily used to regulate your engine's temperature. It absorbs excess heat from the engine and dissipates it through the radiator, preventing overheating. It also contains additives that protect the engine and radiator from corrosion and scale buildup. Using the correct coolant is critical for maintaining your vehicle's health and performance.
An internal combustion engine generates a tremendous amount of heat. Coolant, a mixture of antifreeze and water, circulates through passages in the engine block and cylinder head, absorbing this heat. It then flows to the radiator, where air passing through cools it down before it cycles back to the engine. This continuous loop maintains a stable operating temperature, which is essential for engine efficiency and longevity.
Beyond temperature control, coolant serves several other vital functions. The "antifreeze" component prevents the fluid from freezing in cold weather, which could crack the engine block or radiator. Conversely, it also raises the boiling point of the fluid to prevent overheating in summer. The chemical additives in coolant are equally important. They lubricate the water pump seal and protect metal components (like aluminum heads and iron blocks) and rubber/plastic parts from corrosion and degradation.
Over time, these additives deplete, and the coolant becomes acidic and less effective. This is why manufacturers specify coolant change intervals, typically every 30,000 to 100,000 miles, depending on the type. Using the wrong coolant can cause rapid additive depletion and lead to expensive damage.
| Coolant Type | Common Color | Typical Change Interval (Miles) | Key Characteristics |
|---|
| IAT (Inorganic Additive Technology) | Green | 30,000 | Traditional formula with silicates and phosphates for fast-acting protection. |
| OAT (Organic Acid Technology) | Orange, Red, Pink | 50,000 - 150,000 | Long-life coolant for specific GM, VW, and other manufacturers. |
| HOAT (Hybrid Organic Acid Technology) | Yellow, Turquoise | 50,000 - 150,000 | A hybrid of IAT and OAT, common in Ford, Chrysler, and European cars. |
| Si-OAT (Silicated HOAT) | Blue, Purple | 100,000+ | Advanced formula for many Asian manufacturers like Honda and Toyota. |
Always consult your owner's manual to determine the specific type of coolant required for your vehicle. Simply checking the level in the overflow tank monthly and following the recommended service schedule are the best ways to ensure your cooling system functions properly for years to come.
