Why is the water temperature low when the car just starts?

[DanteLynn]

This is a normal phenomenon. When the car just starts, the engine temperature has not yet risen, so the water temperature is also low. Here is some relevant information: 1. The reason for low car water temperature is usually a damaged thermostat or the cooling fan running continuously. The thermostat is a component that automatically acts as a valve based on the engine's water temperature, generally installed at the outlet of the radiator and the inlet of the water pump. 2. When the coolant temperature is low, the thermostat blocks the low-temperature coolant from the radiator, preventing it from entering the engine water jacket, allowing the water temperature in the jacket to rise quickly—this is the small circulation. If the water temperature rises to a certain level, the valve gradually opens, and the coolant from the radiator begins to circulate again, allowing the coolant to flow through the radiator, slowly increasing the water temperature and dissipating heat to the atmosphere through the radiator, maintaining the engine water temperature at an appropriate level—this is the large circulation.