Why is the engine temperature high when the radiator is full of water?

[DelAna]

Here are the reasons why the engine temperature is high when the radiator is full of water: 1. Excessive scale buildup in the radiator and engine water jacket: Too much scale can lead to poor heat dissipation, causing the water temperature to rise. External dirt on the radiator or blockages between the air conditioning condenser and the radiator can also result in poor radiator cooling, leading to high water temperature. 2. Thermostat failure preventing it from opening: A damaged thermostat can prevent coolant from smoothly entering the radiator to form a large circulation loop, causing the water temperature to rise quickly. If the thermostat cannot open or does not open flexibly, the coolant cannot circulate through the radiator, resulting in excessively high temperatures or intermittent high temperatures. 3. Water pump damage or drive belt slippage causing poor pump performance: If the water pump cannot rotate normally to generate sufficient water pressure, it will reduce the flow rate of the coolant. The circulation of coolant relies on the water pump to apply pressure, forcing cooled water from the radiator into the engine water jacket and pushing out the heated coolant. If the water pump is not functioning properly and cannot generate adequate pressure, the flow rate of the coolant circulation decreases, leading to poor heat dissipation and excessively high coolant system temperature.