Can Coolants with Different Freezing Points from the Same Brand Be Mixed?
3 Answers
Coolants with different freezing points from the same brand can be mixed. However, different brands of coolants may have varying production formulas. Mixing them may cause chemical reactions among the additives, leading to their ineffectiveness. How to Choose a Coolant: The basic indicators of a coolant are its freezing point and boiling point. Coolants available in the market come with freezing points such as -15°C, -25°C, -30°C, -40°C, etc. Generally, it is advisable to choose a coolant with a freezing point at least 10°C lower than the lowest temperature in your region. How to Determine If Coolant Is Low: Observe the coolant warning light on the dashboard. If it lights up, it is likely due to low coolant levels, though it could also be triggered by excessively high engine temperature. Check the coolant reservoir. If the fluid level is below the minimum mark (MIN), do not continue driving and promptly add coolant. Check the water level indicator on the coolant tank. The normal coolant level should be between the maximum and minimum marks. If the coolant is below the minimum mark, it indicates a shortage.
I once made the mistake of mixing coolants from the same brand but with different freezing points in my previous car. I thought it wouldn't be a big deal since they were from the same manufacturer, but after a few months of driving, I noticed issues with the engine cooling system—the water temperature kept fluctuating. Upon inspection, it turned out that coolant sediment had clogged the pipes. Although products with different freezing points share similar base components, their additive ratios vary, and mixing them can interfere with chemical reactions. At best, this reduces the antifreeze effectiveness, making the coolant prone to freezing in winter and ineffective at heat dissipation in summer. At worst, it can corrode components and shorten the radiator's lifespan. I strongly advise friends not to cut corners here—always use the exact type recommended in the manual. If you mix a small amount in an emergency, make sure to visit a garage for a complete replacement as soon as possible. Also, check the coolant condition every two years and stick with a suitable brand and freezing point for long-term use.
I was also curious about this when I first bought my car, thinking that products from the same brand could be mixed. But after checking information and consulting mechanics, I was shocked. Mixing antifreeze with different freezing points, like -25°C and -40°C, might look the same as blue liquids, but their organic additive formulations differ greatly. Once mixed, they can easily form cloudy sediments. This affects the flow efficiency of the entire cooling system, leading to engine overheating issues. Back then, with my new car, I didn't want to take risks and just used the recommended single type, which felt much more worry-free. If you've already mixed them, don't hesitate—go to a professional shop immediately to flush the system and replace the fluid. Also, mixing is a waste of money—what you save initially might end up costing more in repairs. When choosing antifreeze, always check the packaging instructions, select the right freezing point for your climate zone, and stick to the same product.
