Why does the coolant level decrease?

[McHadley]

Engine coolant reduction can be attributed to the following reasons: 1. Leakage in the engine cooling system, causing the coolant to drain completely: In this case, you need to inspect the entire cooling circulation system from the radiator to the coolant circulation pump, engine inlet and outlet, coolant pipes, and heat dissipation unit for any leakage points. 2. Thermal expansion and contraction: When the engine is cold, the coolant level may be below the minimum line, but after the engine runs for a while, it returns to the middle of the F/L range. It is recommended to check the coolant level before starting the engine. 3. Air pockets in the cooling system: After some time of circulation, the trapped air is expelled, leading to a drop in the coolant level.