Is it okay to mix a little bit of coolant?
2 Answers
It is not recommended to mix coolants. However, if only a small amount is mixed, it will not affect the vehicle. If you must mix coolants, they must be from the same brand. Different brands of coolant have varying production formulas, and mixing them may cause chemical reactions between additives, rendering them ineffective. Method for replacing coolant: Before completely replacing the coolant, conduct a thorough inspection to check for any signs of leaks or cracks in the pipes, with a focus on the five-way hose. The five-way hose gets its name from having five connection points to various parts of the vehicle. Coolant flows through the five-way hose and is distributed to different parts of the car to function. If there is any leakage of coolant in this section, replace the hose or resecure the connections as needed. Drain the old coolant, then flush the fluid channels with clean water. Add clean water to the coolant reservoir, then continue filling the reservoir with water to allow it to flow continuously through the engine cooling system. Start the engine and let it idle for 3 to 5 minutes to circulate the water. Initially, the water draining from the reservoir may appear slightly pinkish. Continue adding clean water until the water runs clear. Note: Don’t forget to remove the heater hose and drain the water from the heater core. After draining for about an hour, add the new coolant through the radiator hose—this allows the coolant to flow quickly into the radiator. Then, add another container of coolant to the coolant reservoir until it is nearly full. Start the engine and let it run for about 10 minutes. During this time, the coolant level will drop slightly as air is purged from the cooling system. Top up the coolant to the "MAXT" mark on the reservoir.
I've been driving for over 20 years and once mixed different brands of coolant, which nearly ruined my engine. Different brands have varying formulations—some contain silicates while others use organic acids. Mixing them can create flocculent precipitates. These residues clog radiator passages, drastically reducing cooling efficiency, leading to overheating in summer and potential freezing in winter. The worst part is they corrode engine metal components, making repairs ten times more expensive than new coolant. My advice: even in emergencies, only top up with the same color and brand. If unavailable, use distilled water temporarily to reach a repair shop. Cooling systems can't withstand abuse—always flush pipelines thoroughly with equipment when changing coolant.
