Will the fuel consumption be high if the car does not have a thermostat? When should the car thermostat be opened?

The car thermostat is a component that controls the coolant. It can sense the temperature and provide a suitable temperature environment for the engine to run. Some people find that the car water temperature is high and think that it can be cooled without a thermostat, and the thermostat seems to be dispensable. But in fact, if there is no thermostat, fuel consumption may increase. Let's learn more about it!

Will the fuel consumption be high if the car is not equipped with a thermostat?

Not installing a thermostat will waste fuel.

The best operating temperature of the engine is between 80 and 90 degrees. In this temperature range, the fuel is atomized well, the combustion is more complete, the engine resistance is minimal, the mechanical wear is minimal, and the engine efficiency is the highest. If you want to maintain the water temperature of the engine between 80 and 90 degrees, the thermostat is the most critical, because the function of the thermostat is to maintain the engine operating temperature.

If the thermostat cannot be opened, the engine will be overheated. If the thermostat is not closed tightly, the engine will be underheated! The current electronic fuel injection vehicles have a temperature compensation program. When the ambient temperature is low, the fuel injection amount will be automatically increased, and the idle speed will be increased to make the engine heat up quickly. After the temperature is normal, the fuel injection amount and idle speed will return to normal. Therefore, if the thermostat is damaged and not closed tightly, it will also cause the engine fuel consumption to increase, especially in winter. If the thermostat is damaged and the engine water temperature is too low, not only will the warm air not be hot, but it will also cause the engine carbon deposits to increase.

When does the car thermostat open?

The car thermostat usually opens after the water temperature reaches the preset value. The thermostat setting values ​​of vehicles from different manufacturers and brands are also different. Most of them open when the water temperature is above 80 degrees and are fully opened at around 102 degrees.

There is no direct correlation between the thermostat opening and the fan, they are both related to the water temperature. The fan is controlled by the ECM according to the vehicle speed, engine coolant temperature, refrigerant pressure and air conditioning ON signal. Under normal circumstances, the thermostat opens first, the temperature is around 82 degrees to 89 degrees (depending on the model), and then the fan starts to operate when the water temperature rises to above 95 degrees.

When the coolant reaches a certain temperature, the fan will run to dissipate heat from the engine. If the water temperature does not reach the specified value, the cooling fan will also run when the air conditioner is turned on. The engine water temperature often fails during operation. The fault location is different in different situations. In some cases, the fan motor is broken and the thermostat can work normally, while in some cases, the thermostat fails. Any fault between them will cause the engine to overheat.

How the Thermostat Works

A normal engine has two cooling cycles, a small cycle and a large cycle.

When we start the car from cold, the thermostat is closed. The water pump only circulates a small amount with the water channel in the cylinder liner, and the coolant only circulates around the engine, which allows the engine to heat up as quickly as possible, thereby reducing engine wear and vehicle fuel consumption. When the temperature reaches above 80°C, the thermostat gradually opens, the water pump circulates a large amount with the water tank and the cylinder liner water channel, and the coolant circulates through the engine radiator, thereby achieving the purpose of cooling the engine and ensuring the normal operating temperature of the engine.