What happened to Dodge Ram pickup truck when it was cold?

1. The water temperature sensor is faulty. Because the water temperature sensor is installed on the water jacket of the engine cylinder or cylinder head and is in direct contact with the cooling water, it can measure the temperature of the engine cooling water. If the water temperature sensor fails or fails, and the engine ECU detects that the output signal of the water temperature sensor is unreliable, it will intervene to use the substitute value, which is also for the purpose of protecting the engine, which will lead to the instability of the water temperature meter pointer of the automobile, and will also be accompanied by the difficulty of cold start and speed increase of the automobile.

The thermostat is broken. The function of the thermostat is to automatically adjust the amount of water entering the radiator according to the temperature of cooling water, and change the circulating range of water, so as to adjust the cooling capacity of the cooling system and ensure the engine to work in a suitable temperature range. We can touch whether the inlet and outlet temperatures of the thermostat are the same by hand. If the thermostat is damaged, it will also affect the normal working temperature of the engine, resulting in instability of the water thermometer.

3, cooling system failure, we have to check whether the engine cooling system leaks, whether the water pump continues to work, which is also the reason why the car water temperature is hot and cold.