A7 incident
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Urgent Need To Improve Chinese Style Service System From A7 Incident

As one of the representative models of domestic high-end heavy trucks, HOWO A7 of SINOTRUK has been highly concerned since it was listed. Recently, the use of an A7 owner of the truck Home Forum has attracted a lot of attention, but this event is not as dazzling as the various halos shrouded in HOWO A7, because some engine faults have brought a lot of troubles to users of A7 incident .

First of all, let’s meet Master Qu, the party to the A7 incident. His ID in the forum is “looking2009”. Everyone in the QQ group calls him “mist Fangfei”. In this article, we’d better call him master Qu. Master Qu has driven for several years before. From the first Steyr series of heavy truck, to the later liberation and Shaanxi Automobile Aolong, and then to the current HOWO A7, he has been driving for more than 8 years and has rich experience.

A7 Engine Fault Door Event Review

From his posts on the forum, many people who are concerned also have a general understanding of the whole event. Many problems have been found and eliminated since the car collection inspection. I won’t repeat them here. For details, please refer to A7 initial experience of car collection preliminary inspection and hidden danger elimination.

The fuel consumption of master Qu’s A7 remains high. At the speed of about 90-105km / h, the fuel consumption has been approaching 60L. On August 28 this year, an inspection was carried out at Jinan service station. After the cylinder breaking test, it was found that one cylinder did not inject fuel, and one cylinder seemed to spray but not spray. The service station resolutely replaced the fuel injector. In the two sports car tests in early September, the standard load speed was about 90, and the fuel consumption was about 43. For more information about this repair process, please refer to the chapter on insufficient power and fuel consumption of atypical A7 fault cases.

Replace Piston Ring In Guanglong Service Station

After replacing the fuel injector, the problem has not been completely solved. Master Qu’s A7 Sanjin heavy truck Guanglong service station. You can also see the next thing in the forum post “A7 first experience – service experience between me and A7 relatives”.

When I entered the service station for the first time, I disassembled the engine and found that there was thick carbon deposit on the piston ring. The service station was quick to “replace what is broken” and replaced the piston ring and valve oil seal for master Qu’s A7.

There was also a small episode during the period. Due to the lack of accessories at the service station, there was no connecting rod screw of A7 D12 engine, and even borrowed a bolt on Weichai WP12 engine from the nearby Futian service station, This is clearly stated in the after-sales maintenance instruction of SINOTRUK that “special attention: genuine sinotruk connecting rod bolt accessories must be used when replacing connecting rod bolts. For engine faults caused by the use of fake and non sinotruk connecting rod bolts, no claim will be made and the resulting losses will be compensated”. This borrowing of bolts has also brought a lot of trouble for subsequent maintenance and replacement.

Second, Enter The Service Station To Feel The So-Called "Family" Service

It took two days to replace the piston ring for the engine, but the problem was not completely solved. I ran twice and found that the problem was still the same, and later it was even more serious than before. However, master Qu came to the service station again. The engine of the new car has been disassembled twice, and this maintenance process also made master Qu really feel the “family service” publicized by China heavy truck!

After the engine was disassembled, it was found that the piston rings of cylinder 5 and cylinder 6 were aligned again. The connecting rod bush had turned and obvious marks were worn on the connecting rod. As for the first time, the piston ring was replaced, but this replacement took more than 8 days. After reading master Qu’s car repair experience, Xiaobian couldn’t help feeling ashamed. Here is a simple list of the whole maintenance experience.

If you carefully read Master Qu’s post, you will find that there are many details that make people laugh and cry in the whole process, such as washing parts, asking users to buy gasoline, wiping parts, towels, toilet paper, grinding valves, and grinding abrasives; 6 connecting rods, 11 bolts and one broken one sent by heavy truck to the service station; Adjusting the valve depends on the feel. Master Qu is not at ease. He took a taxi and bought them a feeler gauge… These details are very different from the “family service” proposed by China heavy truck.

Forum Posts Attract Attention

The development of the network also makes information transmission more convenient. After master Qu sent his information, it attracted the high attention of many truck netizens. The discussion of netizens also made sinotruk feel the pressure of public opinion, and some senior leaders began to pay attention to the incident.

Application For Engine Replacement At Sanjin Service Station

The second long maintenance still did not completely solve the problem. Master Qu only drove the car to the service station for the third time. Perhaps because of the concern of senior leaders, the attitude of staff has been greatly improved and the efficiency has been greatly improved. Because the problem has not been solved, the manufacturer also accepted the user’s request to replace the engine.

User'S Voice
Huge Loss Caused By Low Efficiency

For the attitude and efficiency of the service station, the description in master Qu’s post has given us the most intuitive feeling. As an ordinary consumer, “we don’t have much energy to argue about those. Let the top management of heavy truck discuss the rest. We can only complain, but we don’t have the ability to reverse it, just because we can’t control that component, ha ha!”

In a telephone interview with master Qu, master Qu said that the delay cost caused by this maintenance is a very big economic loss for him. The economic benefit of pulling coal every day is about 1300-1400 yuan. Take the second inbound maintenance as an example, it has wasted nearly 10 days, and the direct loss has reached more than 10000 yuan.

Master Qu’s car is also a loan purchase, and he has to repay to the bank every month. If he buys a car with a loan, the user must know the pressure of repayment. It can’t be delayed for a day.

Doubts About The Process

During the whole maintenance process, master Qu also mentioned the relevant processes of heavy truck in dealing with such problems. First, replace the valve oil seal or piston ring, or both, and then track and understand. If the problem is not solved, execute the second step, replace the four supporting parts, and then track and understand. If the problem is not solved, execute the third step, replace the engine, The premise is that the oil fuel ratio reaches three thousandths, or find other solutions!

For the maintenance process mentioned in the third service station, Master Qu also has some doubts: “If they follow this method, how long will it take from the time when the engine is reported for repair to the time when they complete this process? I am not interested in calculating, but I know that it takes a long time! But I have never found out in their process. Who is responsible for the expenses and losses caused to users? I don’t talk about the production of heavy truck Whether the product is mature or not, I just want to know how this process is generated. Can it be said that a heavy truck engine technology center has formulated such irresponsible processes and regulations? “

Expert Analysis

Why can’t master Qu’s car completely solve the problem? For the situation of this car, Xiaobian called Mr. Qi Bing, a truck technical expert. He has been paying attention to the whole process since master Qu bought the car and knows the whole incident very well.

According to the analysis of Mr. Qi Bing, from the fault situation of the vehicle, the service station simply changed the piston ring for master qu. at that time, he did not think of the real reason of the vehicle, so the problem could not be completely solved. The following faults were just repeating the previous faults.

In fact, the curse should have been buried in the process of delivering the car. We should also notice a small detail of master Qu when collecting the car. The new car found a lot of water in the filter cup of the oil-water separator, which shows that the driver of the delivery company added inferior diesel to the car in order to save cost.

In the case of master Qu, Mr. Qi Bing believes that the inferior diesel added by the delivery company contains colloid and sulfur. From the piston picture, we can see that the hard carbon deposit pulls the piston head and there is deflagration and ablation between the first ring and the second gas ring. At the same time, the hard carbon deposit and colloidal carbon deposit cause the decline of the carbon removal ability of the first piston ring, Inflexible rotation leads to frequent counterpart.

Influence Of Inferior Diesel On Engine

In order to meet higher emissions, the internal of the current engine is more precise, especially the fuel injector and other components, which also puts forward higher requirements for fuel quality. Poor diesel containing water or impurities will cause very serious damage to the engine.

Dust or impurities will accelerate the wear of precision coupling parts. Diesel oil that does not meet the standard is easy to burn insufficiently, resulting in insufficient engine power. Poor quality diesel fuel has high sulfur content, which will generate too much acid corrosion after combustion, and high sulfur diesel fuel will generate hard carbon deposit after combustion, scratch the cylinder wall and increase mechanical wear. For diesel engines with common rail system, water in diesel will also cause excessive wear of fuel injectors.

Therefore, inferior diesel is easy to cause abnormal combustion of the engine, carbon deposition, corrosion and wear. After receiving the car, master Qu also found that the sound was abnormal. Although he also purchased Parker oil-water separator for protection, carbon deposits had been formed in the cylinder after the delivery company added inferior oil, so the problem still existed when he entered the service station for the second time.


Master Qu’s experience can be said to be an epitome of the domestic heavy truck market. As a link of direct contact with users, after-sales service quality is directly related to users’ impression of the brand, and the service station also represents the image of the brand. At the same time, a perfect after-sales service system also requires all service stations to maintain the same high level. Even if some service stations do very well, individual cases of poor service quality will also waste all other efforts. In order to establish a good image in the hearts of users, manufacturers must control the quality of raw materials and accessories, the process of product production, assembly and transportation, and then the final after-sales service. Every small link needs to be strictly controlled, and the double control of product and service quality can establish a real good brand.

As of press time, master Qu’s car has been replaced with a new engine, and the truck home will continue to pay attention to the subsequent use. This incident has attracted the attention of many people on the network. Although it has been solved in the end, we hope that all manufacturers will reflect on this incident, improve the product quality monitoring and service system as soon as possible, and prevent the recurrence of such incidents.

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