How Often Should Coolant Be Replaced?
2 Answers
Vehicle coolant generally needs to be replaced every 2 years or 40,000 kilometers. This is just a reference interval. For commercial vehicles with higher mileage, the replacement cycle should be shorter. Since driving conditions vary for each vehicle, the actual replacement should be based on usage. Check the coolant level regularly and top it up if it's insufficient. If suspended particles, sediment, discoloration, or deterioration are observed in the coolant, replace it immediately and flush the system. Coolant replacement procedure: Before a complete coolant replacement, conduct a thorough inspection to check for leaks or cracks in all hoses, with special attention to the five-way connector pipe (named for its five connection points distributing coolant to different parts of the vehicle). If any coolant leakage is detected at this component, replace the hose or reseal the connections as needed. Drain the old coolant, then flush the channels with clean water. Add water to the coolant reservoir and continuously circulate it through the engine cooling system. Idle the engine for 3-5 minutes to facilitate water circulation. Initially, slightly pinkish water will flow out—continue flushing until clear water emerges. Remember to disconnect the heater hose and drain the heater core completely. Approximately one hour after draining, pour new coolant into the radiator hose for rapid filling. Then add another batch to the reservoir until nearly full. Run the engine for about 10 minutes; as air escapes from the system, the level will drop. Refill to the "MAX" mark on the reservoir.
Over the years of repairing cars, I've seen too many cases of radiator corrosion caused by expired antifreeze. For regular family cars, it's recommended to change it every 40,000 kilometers or 2 years, but it depends on usage. Vehicles that frequently travel long distances endure high thermal loads, and some brands' original antifreeze turns black and foams after just 30,000 kilometers. I remember last year, an off-road vehicle hadn't changed its antifreeze for five years, resulting in corrosion perforation of the aluminum radiator, costing over 8,000 yuan for major repairs. Always test the freezing point before replacement; -25°C is the basic requirement. If you notice rust-colored flocculent in the fluid or unexplained drops in the fluid level, don't hesitate—test and replace it immediately.
