Many car failures are directly related to temperature-extremely hot or cold environments will affect the stability of parts and cause wear. The extreme heat will cause a lot of pressure on the cooling system of the vehicle, coupled with the frequent use of air conditioning, leading to varying degrees of “internal fire” in the engine. Once there are symptoms of “fire”, leakage will follow.
Nothing is more closely related to heat dissipation than antifreeze coolant, as the heat dissipation medium of the engine, the antifreeze coolant channel runs through the engine and dissipates heat through the front water tank. Many people will ignore the importance of antifreeze coolant, super-periodic use or even the use of inferior antifreeze coolant has become the most common mistake in the car, although it will not be abnormal in a short period of time, but after the passage of time, the engine will have varying degrees of failure. This issue of “Ika repair shop” has encountered such a case.
An overview at the beginning:
1. When a vehicle has an antifreeze coolant alarm, in addition to adding antifreeze coolant, it is also necessary to check for leakage
Second, the cooling system is complicated, and overhauling in 4S stores can improve efficiency:
1. 4S store has a full range of special tools to fully check the cooling system.
2. Technicians in 4S stores have a better understanding of the common faults of car models, specializing in cars, and are more efficient.
Third, the inferior antifreeze coolant will cause the associated failure of the cooling system:
1. The additives in the inferior antifreeze coolant are insufficient, and their long-term use will produce corrosiveness.
2. Poorly qualified repair shops usually use inferior antifreeze coolant and use poor quality accessories to increase the probability of failure.
4. 4S stores insist on using the original factory antifreeze coolant in order to:
1. Protect the engine cooling system. The antifreeze coolant of the original factory is the product customized by the antifreeze coolant manufacturer for the main engine factory, which is more in line with the characteristics of the brand vehicles.
2. The performance of the original antifreeze coolant is stable, even if it is used for a long time, it will not be as corrosive as the inferior antifreeze coolant.
3. When the original factory antifreeze coolant is used together with the original factory accessories, it can be excluded that the damage of the spare parts is not caused by the antifreeze coolant, which is convenient for in-store after-sale quality assurance.
5. 4S technician operation code, the condition of the vehicle maintained in the 4S shop is obviously better than that in the repair shop.
–
Antifreeze coolant inexplicable alarm leakage site is very hidden
Our colleague Xiaoyu recently encountered a thorny problem with the cooling system. Let’s start with Xiaoyu’s model, a 2008 2.4L Audi A6L. Although it is a ten-year-old car, the A6L is still spotless, and the halo of luxury brands remains undiminished.
However, recently, the Audi A6L often appears antifreeze coolant level alarm, and more and more frequently, every 100-200km needs to add a small amount of antifreeze coolant, although the amount of liquid added each time is not much, but the existence of the fault will be disturbing.
The loss of antifreeze coolant will directly affect the heat dissipation of the engine. when the mass of antifreeze coolant decreases, the less heat can be absorbed by the engine, and at the same time, the temperature of the only starting fluid in the engine will continue to rise, resulting in high water temperature and boiling. Even the consequences of pulling the cylinder.
As the owner of the car, Xiaoyu has tasted all the procedures checked by the owner and has been closely monitoring whether there is liquid leakage under the car since the alarm malfunction. however, three months later, there is still no obvious leakage under the car. However, it can be determined that the leakage point of antifreeze coolant is small and hidden.
The complicated engine cabin is full of various components and pipelines, and antifreeze coolant leakage may occur in water tanks, water pipe joints, water pumps, engine connectors, or even because of sand holes in the cylinder head, or even in the warm air water tank in the car. The tighter the layout of the engine compartment, the more difficult it is to inspect.
Second, how to avoid detours in fault diagnosis?
Since the last Q3 shoddy brake incident, I think the 4S store is the best place for this Audi A6L. 4S store not only has professional testing equipment, maintenance personnel also have more experience in vehicle models, so they can take fewer detours in the maintenance process. At the same time, 4S store spare parts are also more quality assurance, these factors add up, go to 4S store is perfect for an old car leaking antifreeze coolant.
When you come to Audi 4S store, open the decorative cover of the engine, the water pipe of the water tank will be directly exposed, and the vacuum valve shell in front of the inlet is attached to a very conspicuous layer of pink scale, which is the trace left by antifreeze coolant leakage, evaporation and drying for a long time. These traces provide an important clue for us to locate the leakage point of antifreeze coolant.
When checking the antifreeze coolant leakage, the technician will first pump air into the antifreeze coolant kettle and pressurize it. When there is a leakage point in the pipeline, the air pressure will make the antifreeze coolant leak out quickly from the leakage point, and the pointer of the pressure gauge will drop; while the normal cooling pipeline is closed, the air injected into the pipeline can be kept under constant pressure, and the value of the pressure gauge will not change.
Using this principle, and under the guidance of trace clues, we quickly determined that the antifreeze coolant leakage is just below the inlet. The fault that has plagued Xiaoyu for more than 3 months has finally been found out. After the 10min test, the pressure gauge pointer reading is getting smaller and smaller, at the same time, there is more and more antifreeze coolant under the inlet.
Third, why is inferior antifreeze coolant the chief culprit for the failure of the cooling system?
The experienced technician immediately decided that the leakage should be caused by the poor sealing of the engine “oil-water separator”. If you want to cure the leakage, you must disassemble the engine inlet. The reason for the poor sealing has a lot to do with the quality of antifreeze coolant and accessories.
1. How to avoid the failure caused by the corrosion of antifreeze coolant?
In the process of disassembling and replacing the “oil-water separator”, we have every reason to believe that the use of inferior antifreeze coolant is the chief culprit for sealing ring leakage.
Add Channel
First of all, when releasing the antifreeze coolant of the original car, we found that the water pipes connected to the Audi A6L and the water tank were coated with sealant, which could not have come from the 4S store. Xiaoyu also said that the Audi A6L had been overhauled in the repair shop a year ago, knowing that the repair cost was less than half that of the 4S store, and that he knew nothing about the brand and purchase channels of antifreeze coolant. As a result, the suspicion of inferior antifreeze coolant was magnified again.
Observe the state and smell of the liquid
When you are close to the antifreeze coolant pipe, you can smell a large smell of alcohol. In fact, the real antifreeze coolant is tasteless, but the inferior antifreeze coolant is made by blending water and oil, in which pigment, industrial methanol and recovered ethylene glycol are added, and impurities will be mixed in the antifreeze coolant. Large impurities and inorganic salts will also be formed in the process of use.
Do not use water or mix other brands of antifreeze coolant
Of course, the way to increase the corrosiveness of antifreeze coolant is to mix it with hard water and other brands of antifreeze coolant. In the previous frequent replenishment of antifreeze coolant, small fish have used different brands of red antifreeze coolant, or even added tap water, which will lead to the reduction of ice and boiling point of antifreeze coolant to varying degrees, and chemical reactions occur among a variety of antifreeze coolants, thus corroding the cooling system.
2. the assembly process of the repair shop for replacing inferior antifreeze coolant is poor.
Many cars that have been overhauled for more than 10 years cannot escape overhauling, but Xiaoyu chooses the kind of repair shop that “gets worse and worse”, which will not only solve the original problems, but also cause new failures.
For example, when the engine was installed before, the wires were not tied up according to the original position, but were allowed to be scattered over the ternary catalytic converters, which is not beautiful, and the wires may be baked at a high temperature of ternary. Is extremely dangerous and irresponsible operation.
The technician of 4S store only uses less than 30min to disassemble the inlet, and after removing the inlet, the location of the leakage point is more obvious. It can be seen that during the previous overhaul, the waste gas valve was also replaced.
The pipe accessories around the intake port are as dense as nerves. For example, this kind of hard vacuum tube may break if it is slightly misplaced, and most of the parts of this old car have been discontinued. Can you find a replacement? How long will it take to find it? It’s all unknown. Therefore, this requires the technician to be as skilled as a cook.
After removing the leaking waste gas valve, the direction of the antifreeze coolant and exhaust gas pipeline is clearer. It can be seen that the previously replaced waste gas valve has also been coated with sealant.
After the leakage of the sealing ring, there is still a small amount of antifreeze coolant mixed with the oil, although the oil has not been significantly emulsified, but we finally changed the oil.
The general vehicle cooling system is a sealed system, external dirt can not invade this system, if the color of the antifreeze coolant becomes turbid, it is mostly due to chemical changes in the starting fluid and pipeline materials. These dark substances will make the inside of the antifreeze coolant filling kettle dirty, so most vehicles can judge the antifreeze coolant quality by observing the antifreeze coolant kettle, and this Audi A6L waste gas valve is an extremely rare case.
3. Non-original parts have large errors and are easy to leak.
Why does the repair shop prefer to apply sealant to the interface? This is mainly because non-original parts in the manufacturing mold, can not compare with the original factory in data, materials and other aspects, if you want to obtain strong sealing performance, you need to use sealant.
Excessive sealant will prevent the sealing ring from fully meshing the engine metal section after being pressed, that is to say, there will be a layer of sealant between the sealing ring and the section, and this thin layer of sealant will be the first to crack under the corrosion and pressure of antifreeze coolant, resulting in leakage.
In addition, the material of non-original parts is not as good as the original factory, careful observation of the waste gas valve sealing ring, you will find that the contact surface has been flattened, the deformed sealing ring can not restore the original full shape, in a state of bullet loss.
The manufacturing process of the sealing ring of the original waste gas valve is obviously better, in addition to sufficient plumpness, it also has good elasticity, just like this, as long as the technician is fastened with the prescribed screw moment during installation, there is no need to apply sealant.
The inner wall of the water channel of the original waste gas valve is also very clean, and the smooth inner wall can reduce the resistance of the antifreeze coolant flow, at the same time, avoid the impurity pollution of the inner wall and prevent the pipeline from being blocked.
4. Why does the 4S store refuse to use the antifreeze coolant brought by the car owner?
Some car owners want to reduce the maintenance cost of their vehicles in 4S stores and ask technicians to add the oil and antifreeze coolant they bought online or in Auto parts City. When they encounter this situation, 4S stores will refuse for the following reasons:
1. The original factory antifreeze coolant is specially customized for brand models.
Although brand-specific oil is the product of automobile manufacturers looking for oil manufacturers to label, oil manufacturers will develop the most suitable oil for different brands of models. When developing the original oil, manufacturers will determine the content of additives in the oil according to the adjustment and working temperature of engines of different brands, so as to maximize the protective effect of the oil.
2. The performance of the original antifreeze coolant is more stable.
The original antifreeze coolant has a wider range of temperature resistance, which can not freeze at-40 ℃ at low temperature, and can be adapted to most parts of China. The reason why the antifreeze coolant needs to ensure an adequate freezing point is that the volume of the liquid expands when it freezes, and once the antifreeze coolant freezes, it will break the water tank or even the engine waterway.
At the same time, the antifreeze coolant has a very high boiling point, but it still has good thermal conductivity at 106℃, which can take away more heat from the engine, prevent the occurrence of thermal attenuation, and is of great help to reduce engine wear and prolong engine life.
3. The joint and several failures caused by the non-original antifreeze coolant can not be divided.
The original antifreeze coolant not only has the characteristics that are more suitable for the brand model, but also has more stable performance. based on these two points, 4S store can ensure that the vehicle has a long durability in the later use.
Take Xiaoyu A6L as an example, if the 4S store replaces the waste gas valve and adds non-original antifreeze coolant again, once the exhaust valve sealing ring leaks again, it is difficult to assess whether it is the problem of the original spare parts or the corrosion of the original antifreeze coolant. However, if all the original accessories are used, even if they leak again, the 4S store will carry out the after-sale quality assurance policy and repair again for the car owners.
Corrosion cases caused by low-quality antifreeze coolant are not uncommon in 4S stores. The most common failure is “rotten water tank”. There happens to be a section of corrosion-broken water tank joint next to the station, and the fiber can peel off by pressing gently with your fingernails.
Fifth, the operation standard of 4S store to reduce the probability of failure from the installation link.
When installing a new “oil and gas separator”, 4S shop technicians will not apply any sealant. They only need to place the original parts and tighten the screws to standard torque with a torque wrench, so that the sealing ring will not leak at all.
Before installing the water pipe, the technician will also replace the sealing ring on the pipe head and spray lubricant to prevent the new sealing ring from curling due to dryness during insertion.
After installing the air inlet back, the technician will still tighten the air inlet screws with a torque wrench and carry out construction in full accordance with the standards.
Having experienced two 4S shop maintenance experiences, my impression of 4S shops is getting stronger and stronger. In the huge maintenance workshop, there are no fewer than 10 Audi A6Ls that are more than 10 years old, but it is difficult to find situations like ours that leak oil and leak water. It is understood that these cars are maintained and repaired in 4S shops throughout the entire process. Compared with cars of the same age that often visit repair shops, these cars are considered to be youthful and permanent.
Editor’s summary: The reason why the theme of this issue of “Aika Car Repair Shop” revolves around “returning to the 4S” is to explain the importance of original parts. Although accessories and oil and water may not seem to be conspicuous, they will cause damage to related parts in the system.
Returning to this issue of failure cases, it was really a loss for car owners to use inferior anti-freezing coolant at the beginning. In the long run, from the perspective of time and money cost, original anti-freezing coolant will bring car owners a more convenient car experience. After all, the original anti-freezing coolant is specially made for brand models, and the biggest advantage of the original anti-freezing coolant is the unique condition of the vehicle.
If you want to distinguish the quality of antifreeze coolant from the channel perspective, it may be difficult for even professionals to distinguish, let alone inexperienced consumers. However, engine failure caused by misuse of inferior anti-freezing coolant will aggravate the “internal fire” of the engine cooling system. At this time, using the original “gunpowder remover” in the 4S store will surely be cured by the medicine.
BartFerdinand 
9 
April 1, 2024 
