Why is the water temperature high when the car is idling? Why is the car humming when idling?

When starting the car or driving, the owner may need to idle the car. At this time, the engine is in a high-speed idling state and will emit heat. There are fans and water tanks in the vehicle to cool it down. If the temperature is always high, you should consider whether there is a problem. Let's learn more about it.

Why is the water temperature high when the car is idling?

There are three main ways to cool down a car engine's cooling system. First, cooling water is circulated throughout the entire circulation system to cool it down. Second, the airflow generated by the radiator fan dissipates the heat from the high-temperature cooling water in the radiator. Third, the airflow generated by the oncoming air when the car is driving cools the high-temperature coolant in the radiator.

When the car is idling, the water temperature is too high mostly because the airflow cannot be used to cool the coolant in the cooling system.

When the car is idling, it can only rely on coolant and fan to cool the cooling system. When the cooling efficiency of the fan is slower than the speed at which the engine water temperature rises, the engine water temperature will rise. This is one of the reasons.

Secondly, the radiator fan is driven by the operation of the engine. When the car is idling, the engine speed is slow and the fan's work efficiency is also reduced. It cannot provide enough airflow to cool the high-temperature coolant in the radiator or the heat dissipation efficiency is not as fast as the engine's heating speed, resulting in an increase in the engine water temperature.

Why does the car make a buzzing sound when idling?

Idle humming may be caused by poor idle operation.

Unstable idle speed, engine shaking, idle speed is too high and exceeds the upper limit, idle speed is too low and less than the lower limit, or idle speed is not smooth. These phenomena are related to the failure or malfunction of components such as injectors, oxygen sensors, air flow sensors, exhaust gas recirculation valves, and poor connection of control circuits and vacuum lines.

Should I turn off the car if it idles for more than 3 minutes?

Whether from the perspective of energy saving and environmental protection or for engine protection, the engine should be turned off!

When the engine is idling, the fuel supply system provides the engine with a relatively rich mixture. The idling fuel consumption of an ordinary mainstream displacement car is generally about 1.5 to 3 liters per hour. A simple calculation shows that these ordinary mainstream models consume about 0.5 ml of fuel per second when idling.

When the car is started, the engine needs to provide a relatively rich mixture, and the fuel consumed at the moment of starting is about 5 to 10 ml.

Theoretically, shutting down the engine saves more fuel than idling. However, taking into account various situations, such as starting wear and tear, the car manual generally stipulates that the engine should be shut down if the idling speed exceeds 60 seconds.

Finally, when the engine is running at low speed, the fuel atomization is poor and the combustion is incomplete, so it is very easy to produce carbon deposits inside the engine. Moreover, when the engine is idling, the exhaust emissions are also poor, which is not good for environmental protection.