Do I need to drain the old coolant before adding new one?
2 Answers
Adding the same brand and model of coolant does not require draining the old coolant, but adding a different brand or model requires draining the old coolant. Precautions for adding coolant: The general filling amount of coolant should be between the max and min water level marks. It should be added when the car is stationary. After turning off the engine, wait for it to cool down. Adding coolant when the engine is hot may result in inaccurate water level readings. Replacement cycle instructions: Coolant needs to be checked and replaced regularly, approximately every two years or 40,000 kilometers. The exact timing should be determined based on actual usage conditions.
I always do my own car maintenance, and adding coolant depends on the situation. If the coolant level is just low, there's no need to drain the old one—simply top up the new coolant into the overflow tank. Coolant loss is usually due to evaporation or minor leaks, and replenishing with new coolant won't affect the system's operation. However, ensure the old and new coolants are compatible: most modern coolants are ethylene glycol-based, and mixing different brands may cause chemical reactions, leading to sediment that clogs pipes and damages the engine. It's recommended to stick with the same brand. A complete coolant replacement every two years is ideal, requiring full drainage of the old fluid and system flushing to remove contaminants and ensure cooling efficiency. Regular maintenance extends engine life, and after each top-up, start the engine to check circulation and prevent potential issues.
