Don’t rush to conclusions, let’s talk about the intricacies behind the Toyota oil incident

For a whole month, people restricted going out and worked hard to cooperate with epidemic prevention. Most people spent an unusual Spring Festival. When people's social activities gradually resumed, there were suddenly more discussions about cars. Most of these issues were related to power loss, gas loss, low temperature, etc. caused by long-term parking of vehicles. In this discussion, the issue of increased engine oil in some Toyota models has become a hot topic, so people began to care about the relationship between Toyota's increased engine oil and Honda's increased engine oil last year.

This discussion about increased engine oil coincides with the recall of some Toyota models in the U.S. market. So a question arises. Does the recall of vehicles by Toyota in the United States mean that the increase in engine oil is a global event, and Toyota is treating Chinese customers differently?

Before this thing becomes more interesting, I am quite interested in sorting out the logic behind it.

Is Toyota’s U.S. recall related to engine oil?

It is easy to find information on Toyota's recalls in the United States. The famous third-party media "Consumer Reports" will publish information on almost every manufacturer's product recall.

Of Toyota's four recent recalls, the first two occurred in January 2020, mainly targeting problems with airbags and sensors in some older products, and the other occurred on February 14, 2020. The message reads:

If you just bought a new Toyota or Lexus, your car may need an engine replacement. More than 44,000 cars and SUVs from the 2019 and 2020 model years are being recalled because they can overheat, stall, or even catch fire. Affected vehicles include the 2020 Toyota Camry, Toyota Camry Hybrid, Toyota Avalon Hybrid and Lexus ES300h sedan, as well as the 2019-2020 Toyota RAV4 and RAV4 Hybrid SUVs.

The recall is due to an engine block problem where combustion occurs. Due to manufacturing errors, the engine block may leak coolant or oil, which may cause the engine to stall or catch fire during use. Drivers may first notice warning lights and sirens, increased engine noise, and/or engine smoke. Toyota announced in a written statement that about 250 of the 44,191 recalled vehicles will need to have their engines replaced, but dealers must check the serial numbers on the engine blocks of the recalled vehicles to determine whether they are part of the faulty batch.

It is not difficult to find in this recall information that of the total 44,191 recalled vehicles, only about 250 need to replace the engine, which means that this batch of faulty engines is only a certain batch, and the scope of the impact is not Not big, but the final reason, Toyota wrote like this:

In September 2019, a Toyota-owned factory in Tennessee produced engine blocks for Toyota and Lexus vehicles. According to a written statement from the automaker, a water flow meter at the factory malfunctioned while some engine blocks were being cast. As a result, this standing water does not cool properly, causing cracks to form.

The conclusion is obvious. This is a quality problem caused by negligence at Toyota's U.S. factory and has nothing to do with the Chinese market. Therefore, the recall on February 14 is not related to the engine oil incident in China.

The most recent recall information was announced on March 4, and the content is as follows:

Toyota and Lexus will recall approximately 1.8 million vehicles from the 2013 to 2019 model years because they The fuel pump may stop working, which may cause stalling or dragging while driving. This problem increases the risk of a collision, especially when the vehicle is traveling at high speeds. Some of these vehicles are being added to existing recalls already announced in January. If the fuel pump fails, drivers may notice that the vehicle's engine begins to run rough and a warning light appears on the dashboard. If the engine stalls, it may not be restartable.

It turns out that this recall was not due to an increase in engine oil, but a problem with the fuel pump.

When there is a problem with the fuel pump, a warning light will appear on the instrument and the engine cannot be restarted. When some domestic Toyota models encounter an increase in engine oil, none of the fault lights will light up, and the fuel pump will not affect the engine oil, so This recall can also be excluded.

In other words, although Toyota has carried out recalls in the United States, the reason for these recalls is not the reason for the increase in engine oil in the Chinese market. Moreover, when reviewing Toyota’s U.S. recall information, we found that Toyota has almost every vehicle in the United States. There are recalls every month, and the same goes for other brands. It seems that "recalls" are a normal thing in the US market. Although there are "recall" cases in China, most car companies do not want to present public information. They mainly issue internal documents and directly make "claims" when consumers perform repairs and maintenance. In the final analysis, the main reason is that Chinese consumers lack a rational view of the recall.

What’s going on with the increase in Honda engine oil?

Two years ago, Honda had an oil increase incident in China. The main target of the incident was only one car - Honda CR-V. The engine model involved was L15BL, which is a turbocharged engine. . This engine is also widely installed in other models, with slight differences in power, but there have not been a large number of complaints in those models.

If you look back on Honda’s increase in engine oil, there will be two interesting points:

CR-V was a new car launched that year, and quality issues were the first priority. It is very common to appear in years, which means there is indeed a problem with the engine.

The target is a turbocharged engine, and it is the highest power version.

From these two points, we can easily draw some inaccurate but close to reality conclusions. Honda engines have defects when they leave the factory, and the defects are mainly caused by turbocharging to increase power.

After Dongfeng Honda investigated this incident, the conclusion became even more interesting. The cold weather in the north presents a completely different situation compared to the warm weather in the south. Complaints are mainly concentrated in the north, which also explains the response to the incident. For users of Guangben's models equipped with this engine and whose main base is Guangdong, it is normal that there are no such complaints.

Dongfeng Honda acknowledged the safety hazards that may be caused by an increase in engine oil when the engine is continuously running at low temperatures (traffic jams in winter), and promised to provide a lifetime warranty for the main parts of the engine.

Why does continued low temperature increase engine oil?

This problem can be said to be simple or complex. It is better to explain the general working principle in a less rigorous but more popular way:

The engine piston will be fully coated with engine oil. On the entire cylinder wall, when the weather is cold, the mixed gas produced by gasoline injection will condense when it encounters the cylinder wall. As the oil enters the crankcase, this part of the gas would have evaporated and burned as the engine ran longer and the oil temperature increased. Under normal circumstances, there will be no increase in organic oil.

Another situation is that when the cylinder temperature and pressure increase, some of the oil attached to the cylinder wall will be burned, but the amount is not large. That is to say, the increase or decrease in engine oil is possible in any engine. It depends on whether it is serious or not.

Honda's increase in engine oil is a typical first situation. Because at low temperatures, car owners frequently drive turbocharged models (side-mounted in-cylinder direct injection) for short distances, and the engine (oil) temperature cannot rise quickly. , the gasoline mixed into the engine oil cannot evaporate smoothly, resulting in an increase in engine oil.

Although Honda's problem has been very clear and has been brought to light, and the case has been concluded, we still have to be concerned about why the engine oil increased, and what is the situation with Toyota?

Why does the amount of engine oil increase?

The increase in engine oil can be summed up in three situations:

Insufficient fuel causes gasoline to wet the wall and be used as "engine oil" for operation. This is the case in Honda engines, and it's exacerbated by the use of side-mounted direct injection.

In order for the engine to become more and more energy-saving, the piston ring tension will be reduced, causing the cylinder wall to be incompletely scraped.

After the oil and gasoline are mixed into the oil pan, the gasoline should evaporate freely but actually does not.

With these three general scenarios, it is easy to explain the increase in Toyota's engine oil. Let's first look at Toyota's stance on this incident, which can be summarized into three points:

Although the engine has Inject engine oil based on the F scale line, but it may increase or decrease. This situation is also prone to occur during personal maintenance, but it is okay and normal. (Note: Line F is the highest line of the oil dipstick)

During cold start at low temperature, a very small amount of incompletely burned gasoline enters the engine oil through the gap between the piston ring and the cylinder block. (The first situation)

When measuring the oil level height, whether the ground is flat, the oil temperature, etc. also have an impact on the oil level height. That is, the higher the engine oil temperature, the thermal expansion causes the oil volume to increase. (Thermal expansion and contraction, the actual impact is small), this is the reason for the emulsification of engine oil.

Toyota explains this: The engine is repeatedly used at low speeds and short distances at low temperatures and unable to warm up (water temperature below 80 degrees, air temperature 10 degrees/30 minutes), and a small amount of condensation water in the engine cannot evaporate. Mixed into engine oil to create emulsification. After the vehicle is driven at high speed, the engine is fully warmed up. As the oil temperature rises, the emulsification phenomenon will disappear after the water mixed in the oil evaporates.

Although Toyota gave this answer, I believe that most Chinese consumers will not buy it. For most Chinese consumers, a car is the most important possession in a family besides the house. Well, when something goes wrong with such a car that should be cherished, consumers don’t want to see or hear it, they just want a solution, no matter how interesting Toyota’s science popularization is.

For this kind of matter, Toyota should refer to China's national conditions and seriously propose a more ambitious plan, such as conducting various inspections and various debuggings, so that consumers can feel that "Toyota is working hard." Only with the impression that the problem is solved will their worries about this product disappear. However, the final solution was to "change the engine oil and remind the car owner to drive more to avoid being idle for a long time."

This kind of treatment plan is difficult to accept in the minds of Chinese consumers. It is just like when we think we are sick and when we get to the hospital, the doctor says "Oh, you are fine, drink more hot water." I feel like this doctor is irresponsible.

The above are all jokes. In fact, there are many interesting things about Toyota's increase in engine oil:

Toyota's increase in engine oil actually happened in the second year of the new car's launch, not the first The annual outbreak is concentrated

During the Spring Festival of 2020, people stayed at home for a long time, and the country entered a state of low-speed and low-frequency car use

The increase in Toyota engine oil mainly occurred in hybrid models. Compression ratio models are the main ones

This happens across the country. It is no longer the case of Honda that is concentrated in the north and scattered in the south. It happens to be cold in the south this year

This is also the most important thing. Throughout the Spring Festival, I saw models with increased engine oil mainly due to long-term idleness, which resulted in increased engine oil. This includes the RAV4 that was circulated on the Internet and experienced engine oil emulsification as soon as the new car was delivered, which is also a case of long-term idleness.

As mentioned before, if an engine has an innate quality problem, it should be a global fault, which is caused by the design level. And the phenomenon of increased engine oil is currently one of Toyota's largest markets. It has not appeared in the United States for the time being, which means that it may not be a product problem, but a usage habit problem.

Combined with the increase in Honda engine oil and the completely different travel patterns during the New Year holiday between China and the United States, China is preventing the epidemic and the United States is celebrating, so China has seen an increase in engine oil and emulsification, which also reflects the "Habit" problem. So, we need to solve the remaining problem, why does Toyota hybrid model have the most serious oil increase?

The THS II hybrid system has been widely recognized in terms of reliability and economy, but the main reason is that the Toyota hybrid system has fewer working conditions for the engine.

Under normal circumstances, a car that is driven by a normal engine can warm up in a short time, but a hybrid car takes longer because it mainly relies on motor drive at low speeds, and When the battery power is low, the engine will immediately turn on full power to supply power to the battery or drive. Therefore, the engine of hybrid vehicles often switches between "not working" and "working at high speed". At this time, the engine temperature, engine oil The temperature cannot rise quickly, so the gasoline wets the wall - enters the crankcase - and cannot evaporate.

If Toyota's oil increase is really the case, then the reason is actually that in the winter of 2019 and the spring of 2020, most consumers used their cars too infrequently due to the epidemic. But if consumers insist on Toyota Toyota can propose a solution. My suggestion is:

The ECU can be rewritten to increase the rate at which the engine water temperature rises, allowing the crankcase ventilation system to start working earlier, and urging consumers to pay attention to the frequency of vehicle use. .

Another suggestion is to refer to Mazda's plan, which uses a huge roar to remind car owners "Don't move, let me warm up for a while" during cold starts. This will create a "fear mentality" in consumers and wait for the sound of the engine. After gradually getting lower, start driving. Over time, you can develop a habit and successfully avoid the increase in engine oil. However, the consequence of adopting this solution is that "everyone in the village knows that you went to work with the Mazda owner early in the morning."

Finally, I believe that as the resumption of work and production progresses, the frequency of car use increases, and the increase in Toyota engine oil will gradually disappear. From my perspective, I think it is mainly due to the increase in last winter. This situation arises due to special circumstances. In essence, it cannot be concluded that the increase in engine oil this time is a mechanical defect or quality problem. We can only look forward to the subsequent development of the matter and whether this phenomenon will be alleviated after long-term driving.

However, rumors stop at the wise, and it is always right to think hard about this phenomenon. The media may not all be impartial. The U.S. recall and the increase in Honda engine oil may have ulterior motives once such unrelated things are connected.

Picture?|?From the Internet

This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.