After the Refeng S2 timing chain engine is overhauled, why is the water temperature high when idling normally?

If the water temperature rises at high speeds, it may be that the engine thermostat is broken. Abnormal operation of the thermostat will cause the engine cooling system to fail to open, causing the water temperature to rise at high speeds. high. In severe cases, it may cause the engine to boil, causing serious consequences of cylinder pull! It is recommended to check and repair immediately when you have time.