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The High Water Temperature Of The Engine Is Actually Because The "Nose" Is Cracked!

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked!

The engine system is a whole, which requires close cooperation of each component to meet the working needs of the engine; Any problem with one of these components will affect the normal operation of the engine. This issue of small rail brings you a case of “small problem” causing “big failure”.

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (2)
The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (3)

The Troubleshooting Steps Are As Follows Of High Water Temperature :

1. Use A Diagnostic Expert To Read The Fault Code

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (4)

The decoder is used to read the fault code, and no historical fault and current fault code are found; At the same time, when the driver reflects that the power is insufficient, the water temperature is too high.

2. Test in place and read the data stream

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (5)

After in-situ test run and reading the data flow, it is not found that the water temperature is high, the inlet pressure and inlet temperature are also displayed normally, and there is no problem with the multi state switch state; It shows that the lack of power is most likely caused by the driver’s heavy load and high water temperature. The next step is to follow the car to read the data flow of high water temperature.

3. Car Following Read Data Stream

When climbing with heavy load, read the data flow, the water temperature is 112 ℃, and the cooling water boils; Therefore, it can be determined that the reason for the lack of power is the high water temperature.

The main causes of high water temperature are: thermostat problems, radiator problems, fan problems and abnormal vehicle driving conditions of high water temperature.

4. Remove The Thermostat, Block The Small Circulation And Let The Cooling Water Only Go Through The Large Circulation.

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (6)

After disassembly, let the driver go out for test run, and the fault remains the same of high water temperature.

Tips:

After removing the thermostat and allowing the cooling water to only go through the large circulation, it is necessary to block the inlet of the small circulation of cooling water to prevent the cooling water from going into the small circulation.

5. Replace The Radiator

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (7)

After installation and commissioning, the fault remains the same.

A new problem was found during the test run. When the temperature indication of the instrument is less than 100 ℃ (at the same time, the water temperature is 90 ℃), the coolant in the expansion tank is “boiling”.

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (8)

6. Disassemble The Engine

Disassemble the engine and check the cylinder gasket.

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (9)

Check the cylinder gasket and no abnormality is found; Next, check the copper sleeve of fuel injector.

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (10)
  • No problem was found in the inspection of the copper sleeve of the fuel injector, but it was found that the nose bridge of the fuel injector of cylinder 5 was cracked during the inspection.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • Replace the cylinder head and let the driver go out for test run again, and the fault disappears.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • In this case, during our preliminary investigation, there was an obvious deviation in the investigation direction, which is related to the fault phenomenon.
  • During the preliminary investigation, only when the water temperature is high (higher than 112 ℃), the water overturning occurs. At this time, we focus on the heat dissipation of the cooling water itself. However, with the investigation, we find that the water overturning also occurs when the water temperature is 95 ℃. At this time, we can determine that the cause of the fault is that gas enters the water channel.
  • The master may have the following questions about the fault case.
  • ● why does cracking at the bridge of the nose cause real high water temperature?
  • 90% of the heat generated by combustion in the combustion chamber is transferred to the cylinder liner through the first gas ring, and the heat is transferred to engine oil and cooling water through the cylinder liner; However, when there are cracks in the combustion chamber, a large amount of heat directly reaches the cooling water without conduction, which increases the heat borne by the water temperature, resulting in the failure of high water temperature when there are cracks at the top of the combustion chamber.
  • ● why didn’t “low-temperature water turning” appear at the beginning, but “low-temperature water turning” appeared later?
  • In general, when the water channel is connected with the combustion chamber, there will be “low-temperature water turnover”; However, when the connected crack is small, the crack will open only under large combustion explosion pressure (high load), resulting in gas entering the water channel and less high-pressure gas.
  • At this time, the water temperature itself is relatively high. When the high-temperature gas enters, the temperature of the cooling water rises above the boiling point, and “turning over” occurs at the same time. The water temperature is high and the water is turned over, which affects our judgment of the fault point.
  • With the passage of time, the crack expands, resulting in a large amount of high-pressure gas entering the water channel in the combustion chamber, resulting in the overturning of the expansion water tank at low temperature.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • The engine coolant boils, which is commonly known as the “turning over” of the engine. In this issue, we will talk about the causes of the turning over of the engine coolant, so as to quickly find the fault point in the troubleshooting.
  • Engine coolant “tipping” can be divided into high water temperature tipping and non high water temperature tipping.
  • 1. When the water temperature is high, the coolant boils when the temperature of the coolant reaches its boiling point. We can see from the instrument that the coolant temperature alarm light is on, but the ECU may not report a fault code.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • The high water temperature and water overturning are caused by the following reasons:
  • 1.1 long time overload operation
  • Long time overload operation of diesel engine will increase its fuel consumption and heat load, resulting in excessive water temperature. Therefore, long-term overload operation of diesel engine should be avoided.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • 1.2 insufficient coolant
  • Regularly check the coolant stock in the radiator and expansion tank, and replenish it in time when the liquid level is low. Because the lack of coolant in the diesel engine cooling system will affect the heat dissipation effect and cause high temperature of the diesel engine.
  • 1.3 fan failure
  • Check whether the wedge-shaped belt of the fan is loose and whether the shape of the fan is abnormal. Because the wedge-shaped belt of the fan is over fed, it is easy to reduce the speed of the fan, resulting in the failure of the radiator to give full play to its due heat dissipation capacity, resulting in excessive temperature of the diesel engine. In addition, the deformation of the fan will also lead to the insufficient heat dissipation capacity of the radiator.
  • The high water temperature of the engine is actually because the “nose” is cracked!
  • For the electromagnetic silicone oil fan and electromagnetic constant temperature fan, in addition to the fan itself, it is also necessary to pay attention to whether there is a problem with the ECU program.
  • 1.4 sundries attached to the surface of radiator
  • Debris attached to the radiator surface is the most common phenomenon. The attached debris will reduce the heat dissipation area and windward area of the radiator, reduce the heat dissipation capacity of the radiator and cause high temperature of the diesel engine. Therefore, the radiator needs to be cleaned regularly.
  • 1.5 poor coolant circulation
  • Insufficient opening of thermostat will reduce the heat dissipation capacity of large cycle of diesel engine cooling system. If the diesel engine is at high temperature, the thermostat can be put into water for heating inspection. Generally, the opening distance of the thermostat is 8-10mm.
  • Poor performance of the water pump will reduce the coolant flow and cause high temperature of the diesel engine. Check the upper and lower water chambers of the radiator. The temperature difference between the upper and lower water chambers is generally 6-12 ℃, and the water pump can be replaced.
The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (11)

Excessive scale will also affect the heat dissipation efficiency of the inner fins of the radiator and reduce the heat transfer capacity of the coolant and cold air. In this regard, the diesel engine cooling system should be cleaned regularly. At the same time, the use of inferior coolant should be avoided to reduce the formation of scale.

2. Non high water temperature turning over is generally caused by gas entering the cooling water channel. For this, our troubleshooting direction is as follows:

2.1 injector copper sleeve

There is cooling water around the copper sleeve of the fuel injector. When it is not tightly sealed, gas enters the water channel, resulting in the turnover of the expansion water tank

The high water temperature of the engine is actually because the “nose” is cracked!

2.2 air compressor

There is a cooling water channel inside the air compressor. In case of loose sealing inside the air compressor, the compressed gas will enter the cooling water channel and the expansion water tank will turn over.

The high water temperature of the engine is actually because the “nose” is cracked!

2.3 cylinder gasket

As mentioned in this case, I won’t go into too much detail here.

The high water temperature of the engine is actually because the “nose” is cracked!

 

2.4 cylinder head, cylinder block and cylinder liner

The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (12)
  1. The cylinder head, cylinder block and cylinder liner will be pitted due to long-term use, resulting in high-temperature and high-pressure gas entering the cooling water channel, resulting in the turnover of the cooling water tank.
  2. The high water temperature of the engine is actually because the “nose” is cracked!
  3. Pictures of engine cavitation are as follows:
  4. The high water temperature of the engine is actually because the “nose” is cracked!
  5. Cavitation generally occurs on the wet cylinder liner. When the piston moves back and forth in the cylinder hole, it constantly impacts the cylinder wall, resulting in vibration and chattering of the cylinder liner. As a result of this vibration and chattering, the relatively slow flow layer of coolant absorbed on the outer surface of the cylinder liner will produce high temperature and quickly form bubbles.
  6. Two characteristics of bubbles in Physics: one is adiabatic; Second, it produces strong corrosion in the subsequent blasting. This phenomenon exists for a long time, resulting in cavitation corrosion.
  7. 2.5 expansion tank cover
The High Water Temperature Of The Engine Is Actually Because The Nose Is Cracked! (13)

The expansion water tank cover mainly plays a role of pressure maintaining and ventilation. When the cover fails, it will be directly connected with the atmosphere, which will not have a great impact on the engine in general. However, in high altitude areas, due to the low air pressure, the engine coolant will boil at 80-90 ℃ and the expansion water tank will turn over.

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