A broken water pump on a car may result in three types of symptoms: unstable idle operation, leakage, and noise.

1. Unstable idle operation
Connected to a transmission belt, the water pump draws cold water from a water tank and feeds it to the engine for the purpose of cooling. A failed water pump can directly affect the engine RPM, leading to speed instability. This phenomenon typically occurs some time after engine startup, and may cause flameout under high power conditions. These signs can give a first clue of the failure of the water pump.

2. Coolant leakage
This is a common fault, and often occurs at the parts near the water pump, due to which some water can be found at the vent of the water pump. Without sufficient coolant, the engine can grow hotter and experience severe wear or even smoke or fire in serious cases. If such symptoms are discovered, first inspect key system parts (cooling fan, radiator, water pump, etc.) for any sign of damage, and do not use the car before the problem is fixed.

3. Noise
A broken automobile water pump can generate abnormal sound. Since noise may result from a failed internal bearing, a loose impeller, or separation between the impeller and the rotation shaft, corresponding parts should be inspected and repaired in time in order to prevent malfunction of the water pump and consequent inadequate heat dissipation of the engine.