Can different types of coolant be mixed when the level is low?
2 Answers
No, they cannot be mixed. Here are the relevant details: 1. Different coolants contain varying chemical components such as rust inhibitors, anti-corrosion agents, anti-foaming agents, and dyes. Mixing them can lead to chemical reactions, causing sedimentation, scaling, and other hazards. Therefore, when topping up coolant, it is essential to use the same brand. If switching to another type of coolant is necessary, the original antifreeze must be completely drained, and the cooling system should be thoroughly cleaned before replacement. 2. Functions of coolant: (1) Winter antifreeze protection. Prevents the coolant from freezing when the car is parked in winter, which could cause the radiator or engine block to crack. The freezing point of the coolant should be about 10°C lower than the region's lowest temperature to account for sudden weather changes. (2) Prevents scale buildup. The coolant should minimize scale formation during circulation to avoid clogging the pipes and impairing the cooling system's heat dissipation function. (3) Prevents boiling. Coolants that meet national standards typically have a boiling point exceeding 105°C, compared to water's 100°C. This allows the coolant to withstand higher temperatures without boiling ("overheating"), meeting the cooling needs of high-load engines to some extent.
It's best not to mix coolants when the level is low, as mixing different brands or types can cause problems. The chemical additives in coolants vary; for example, mixing organic acids with silicates may trigger reactions leading to sedimentation or corrosion. In severe cases, this can clog the radiator, causing engine overheating and damage. With over a decade of driving experience, I've encountered this issue—repairs are expensive and troublesome. As an emergency measure, you can top up with distilled water to temporarily dilute the coolant, but never use tap water, as its mineral content can worsen the situation. Then, promptly replace it with standard coolant. While checking the fluid level, also inspect for any leaks. Regular maintenance and refills can prevent issues. Make it a habit to check before every long trip—it's cost-effective and ensures safety.
