"Gee, I didn't realize that Mr. Ji is still a nostalgic person! The owner of this car has always maintained the car very well, and it is used as a passenger and cargo vehicle! The owner reported that this car has a small problem recently, and the fan is turned off after the car is turned off.

It keeps turning, so Mr. Ji will take a look at it. Several repair shops told the car owner that it is normal, but the car owner said that this is not normal. It was not like this when driving before!"

Zhai Yun asked the cameraman to record Ji Dongqing's various expression changes. The last few programs proved that Ji Dongqing's popular face is not surprising, but it is very likeable.

This can be seen from the repeated broadcasts of these two programs. Two satellite TV stations from other provinces have requested to purchase this program as the finale of this station.

In particular, two TV stations in the Northeast expressed their intention to introduce it, and Heilongjiang Satellite TV was the first to make this request.

Zhai Yun is discussing this matter with the other party. If the trip can be made, Ji Dongqing will not have to travel back and forth to record programs in the future, and can just rent the other party's venue.

"Let's give it a try and get in the car!"

This kind of problem is not uncommon. Ji Dongqing has repaired it before and is worried about it.

After saying hello, Ji Dongqing took the key and got into the driver's seat. Zhai Yun and his gang got in the car through the back door. The interior of the car looked very old, with floral fabrics and a full sense of age.

There is a pendant of Taizu hanging on the rearview mirror. It can be seen that the driver is a long-term sports car driver. The needles on the instrument panel are now a little unresponsive.

Ji Dongqing started the car, but fortunately the car started smoothly. He drove for three miles on the street outside, and other vehicles that encountered Ji Dongqing gave way.

"Did you see, Sister Zhai, you know that no one dares to touch a trolley when it comes out, haha..."

"Don't come here. People are worried about whether your car has insurance. The owner said the car only has compulsory traffic insurance!"

Ji Dongqing and Zhai Yun were chatting and laughing all the way back to the repair shop. The camera in the car filmed the whole process dynamically, and the camera followed them when they returned to the yard.

The engine cover was opened and the car fan was whirring. Ji Dongqing looked at his watch and showed no intention of stopping for a minute.

Connect the computer to the interface and find out the water temperature. The coolant temperature is always above 94 degrees.

"Mr. Ji, do you know the reason for this?"

With the screen grabbing Ji Dongqing's computer screen, Zhai Yun asked in a low voice, the car fan was buzzing too loudly.

"As I said last time, it is not difficult to solve this problem by understanding the principle! There are actually two reasons why the fan cooling temperature cannot be lowered. First, this is a liquid pipeline! As long as it is a liquid pipeline, it involves pumps and valves! If the liquid circulates

If it is smooth, the coolant temperature will be quickly taken away by the cold air from the fan, and the coolant temperature will also drop quickly!"

Ji Dongqing held a blue pencil in his hand and pointed at a component on the engine cooling jacket, which had several tubes connected to the cooling fan.

In fact, Ji Dongqing did not mention one very important thing: the original intention of the thermostat design was actually to save energy.

As a component installed between the engine cylinder head and the water tank. Because the normal operating temperature of the engine is 85°C_95°C, the fuel combustion is most complete at this time, the fuel consumption is the lowest, and the emissions are the best. When the engine just starts, the water temperature is low (especially

Winter), when the engine has just been started, the temperature in the cylinder is very high. In order to quickly increase the temperature of the intake pipe and make full use of the heat in the cylinder, a thermostat is added. This is to allow the engine to heat up quickly and make the engine reach its best working condition as soon as possible.

It also makes the warm air heat up quickly.

"What's the reason why the coolant temperature hasn't dropped for more than a minute? There are two aspects. First, if the pump is broken! The coolant can't flow, then the fan will keep blowing because there is constantly a little bit of coolant.

Squeeze toward the fan."

"When the sensor receives the temperature response, it will command the fan to rotate continuously. This wastes electricity and is very dangerous for the engine. If it fails, the cylinder may explode. Of course, there will also be a prompt on the instrument panel that the coolant temperature is too high. Now

If there is no prompt, then there is a high probability that the pump is not broken!”

Generally speaking, a thermostat is an automatic temperature regulating device, usually containing a temperature sensing component, which opens and closes the flow of coolant through expansion or contraction, that is, it automatically adjusts the amount of water entering the radiator according to the temperature of the cooling liquid.

, change the circulation range of the coolant to adjust the heat dissipation capacity of the cooling system.

The thermostats currently used are mainly wax-type thermostats, which is what this car uses. It is an older model, so it was a bit difficult for Ji Dongqing to check it.

Holding the laptop bag and lowering it, I tried to check the production period of this part before making further judgment. This thing has a certain number of replacements after 50,000 kilometers. If the judgment is wrong, it will be a loss of skills.

In fact, this thing is very simple to make. The internal paraffin filling body controls the coolant circulation method through the principle of thermal expansion and contraction. When the cooling temperature is lower than the specified value, the refined paraffin in the thermostat temperature sensing body is in a solid state, and the thermostat

The valve closes the channel between the engine and the radiator under the action of the spring, and the coolant returns to the engine through the water pump to perform small circulation within the engine.

When the coolant temperature reaches the specified value, the paraffin begins to melt and gradually turns into a liquid. The volume increases and presses the rubber tube to shrink. While the rubber tube shrinks, it pushes upward on the push rod. The push rod exerts an influence on the valve.

The downward reverse thrust causes the valve to open.

At this time, the coolant passes through the radiator and thermostat valve, and then flows back to the engine through the water pump for a large circulation. Most thermostats are arranged in the cylinder head water outlet pipe. This has the advantage of being simple in structure and easy to discharge into the cooling system.

bubbles, Ji Dongqing finally saw clearly the series of numbers on it, and felt confident, with a confident smile on his face.

"It's actually very simple to verify whether it's broken. Turn on the heater of this car and adjust it to the highest setting! Just like now, we put our hands on the heater vent. Although we can't feel the obvious heater now, we can still

You can see air flow and the water temperature has dropped, which proves that the coolant circulation pump is not broken!"

"Exclusion method, the second item! Valve! There is a thermostat in the coolant bribe! This is an integrated part that can not only feel the change of water temperature, but also automatically adjust the opening and closing size of the pipeline and adjust the flow of the pipeline.

Coolant flow!”

"If you change it, there is a probability of more than 90% that the problem will be solved!"

Ji Dongqing pointed at the coolant circuit, and this time the apprentice and Zhai Yun's assistant began to dismantle the thermostat.

This was arranged by Zhai Yun. The other party has been with him for a long time, so it's time to give him some exposure. In a few years, he should retire and let the other party become independent.
Chapter completed!