Why does the car's water temperature fluctuate between rising and falling?

[RyderDella]

The reasons for the car's water temperature fluctuating between rising and falling are: 1. Damage to the thermostat in the engine cooling system; 2. The ambient temperature where the car is located is too low. Larger displacement engines heat up the water temperature faster, while smaller displacement engines heat up slower. If the water temperature exceeds 100 degrees, it indicates a problem with the vehicle's cooling system, and it is necessary to have it checked at a 4S shop. This also indicates that antifreeze will not have this issue. Leakage in the car's cooling system can lead to insufficient antifreeze, which in turn causes the antifreeze temperature to rise. If the antifreeze level is found to be low, the first step is to check for leaks. If there are no leaks, the same type of antifreeze should be added promptly. Do not add tap water or other types of antifreeze to avoid dilution or sedimentation, which can lead to failure or malfunction. Drivers should always monitor the antifreeze temperature while driving. If an abnormality is detected, reduce speed and stop the car, but do not immediately turn off the engine. Check whether the cooling fan and circulation water pump are functioning properly.