For freight drivers, vehicles are not only a means of transportation, but also a partner for making a living and making profits. They spend most of their time eating and accommodation on board. As the saying goes, "If you want to do a good job, you must first use your tools", especially for freight vehicles that undertake relatively heavy transportation tasks, heavy loads, long distances, high attendance rates, and need to be maintained on time to effectively extend their service life. This is the principle of "three repairs and seven repairs".

Generally speaking, it is recommended to maintain trucks every 5000 kilometers, including changing the engine oil and three filters, changing the gear oil around 20000 kilometers, maintaining four wheels every six months, adjusting the brake system every half month, checking the tire pressure every week, and cleaning any debris on the tires. In addition, the consumable parts of the vehicle should also be replaced on time, such as brake pads, wipers, tires, batteries, brake oil, conveyor belts, circuit oil systems, etc.

Many car owners take their vehicles to service stations for maintenance, often listing a long list of maintenance items that appear to be worth spending money on, with costs ranging from hundreds to thousands. However, in reality, some items may not be as necessary and may even have certain side effects. Of course, service station personnel do not explicitly inform them of these matters. Today, let's take a brief inventory of maintenance projects that have some suspicion of intelligence tax.

1. Turbine maintenance

The so-called turbine maintenance is actually cleaning the turbocharger, removing impurities and dust from the blades. The cleaning method is usually to inject cleaning agent into the turbine inlet end, and clean the inner wall of the turbine inlet end by soaking or flushing.

In fact, the air sucked in by the turbocharger is originally filtered through the air filter, not as dirty as imagined, just like pure water that has already been filtered, and there is no need to filter it again. As long as the vehicle changes the oil, oil filter, and air filter on time, there is no need for additional cleaning of the turbine.

2. Tire maintenance

Whether tire maintenance needs to be done depends on the specific operation content. If the recommended tire maintenance items in the store include checking for improper assembly of tires, friction with leaf springs, mudguards, and carriages, normal tire pressure, wear on the surface of tires, and cleaning of stones and other foreign objects inside the pattern, then this type of maintenance project is completely feasible and even necessary.

In fact, most service stations recommend tire maintenance by washing, cleaning stains, and waxing tires. After completion, the appearance of the tires does indeed look new, but it has little impact on actual performance. Of course, if the car owner is particularly concerned about the appearance of the tires, it can also be done.

3. Throttle cleaning

The throttle valve is a controllable valve that controls the entry of air into the engine. Once it malfunctions or is damaged, the EPC light on the instrument panel will light up, causing unstable or no idle speed of the vehicle, difficulty in starting the engine, vehicle shaking, and other phenomena. One of the most common causes of throttle valve failure is the dirty throttle valve.

That is to say, when the instrument malfunction light is not on, the throttle does not need to be cleaned. The car owner said, 'I can also clean it to prevent throttle failure.'. The truth is correct, but the premise is that cleaning the throttle will not have any side effects. At present, there are two main methods for cleaning the throttle valve. One is to remove the throttle valve for cleaning, and the other is to spray cleaning agent into the throttle valve. After cleaning, impurities are discharged through ternary catalysis. Regardless of the type, cleaning the throttle valve once is not only a waste of money, but also a damage to the throttle valve and engine. So if the vehicle can be used normally and the throttle malfunction light is not displayed, it is not recommended to clean the throttle.

The car owner also said, 'After cleaning the throttle valve in the store before, the vehicle really works well.'. In fact, this is not necessarily because the throttle valve has been cleaned, because throttle valve cleaning is usually done in a complete set with oil circuit cleaning, oil change, etc. In other words, if the throttle valve is not faulty, then cleaning is still not done, and there is no difference in use.

4. Clean up carbon deposits

When it comes to the issue of carbon accumulation in vehicles, a series of headlines have been searched online, all titled "Old Driver Reveals Secrets" and "Inside the Repair Shop". Upon seeing it, it turned out that it was a cleaner seller. At present, the problem of vehicle carbon accumulation cannot be completely avoided. If there is too much carbon accumulation, it can easily affect the performance of the engine. Therefore, vehicle carbon accumulation still needs to be cleaned, but the frequency of cleaning does not need to be as frequent as the service station says.

In general, it is sufficient to clean the carbon deposits of a vehicle every 20000 to 40000 kilometers. Excessive cleaning can actually cause a series of side effects, such as blocking the three-way catalytic converter.

5. Additives with diverse functions

At some service stations, staff will also recommend various additives, such as engine anti-wear agents, engine oil additives, engine oil reinforcement agents, etc., which may sound unclear, but the prices are also very beautiful. But is it really necessary?

No need at all. For example, engine oil additives are said to be resistant to wear, corrosion, and have a certain degree of cleaning effect. In fact, the engine oil we use is originally composed of base oil and additives, with the proportion of additives generally not exceeding 20%. Its functions include cleaning and dispersion, extreme pressure and wear resistance, anti-corrosion and rust prevention, oxygen and foam resistance, and improved fluidity. That is to say, if the engine oil really needs to have any additional functions, then the engine oil has already added a certain proportion of these additives at the factory, and there is no need to pay for them separately. Instead of spending money to buy these additives, it's better to save money and buy better engine oil, as the latter is more reliable.

After discussing the maintenance items that can be avoided, let's talk about common misconceptions in vehicle maintenance:

1. Oil only added but not changed

Engine oil is essential in the use of diesel engines. Car owners generally do not forget to check the amount of lubricating oil and add it according to standards, but it is easy to overlook the inspection of engine oil quality and the replacement of deteriorated engine oil, or to avoid cleaning the oil circuit during replacement, which will affect the effectiveness of engine oil use.

2. Improper application and misuse of lubricating grease

Also known as butter, it mainly plays a role in lubrication and sealing, but excessive use can have the opposite effect. In addition, some people like to apply butter on the cylinder gasket and tire nuts, believing that it can improve sealing and prevent rust. However, this actually affects vehicle performance, and in severe cases, it can even lead to vehicle accidents. Therefore, butter should not be applied too much or indiscriminately.

3. Tire pressure too high

Tire inflation pressure is an important factor determining its service life and work efficiency. High or low tire pressure can affect its service life and is not conducive to safe driving. The scientific inflation standard should be based on the standard tire pressure, with slight adjustments to the tire pressure as the temperature changes.

4. The bolt is tightened too tightly

The torque requirements for bolts are generally strict, such as transmission boxes, cylinder heads, tires, connecting rods, and axles. The tightening torque is specified in the manual, and some car owners intentionally tighten the bolts to prevent them from loosening. In fact, this is incorrect because tightening too tightly can easily cause screws or bolts to break, and may also cause slipping and malfunction.

5. Grind the bearing shells with gauze

Due to the difficulty in mastering the scraping technique, some repairmen may use sandcloth to replace the scraping when replacing the bearing shells. This method is highly undesirable in practical maintenance, as the abrasive particles on the sandcloth are harder than the alloy of the bearing shells. During polishing, the sand particles are easily embedded in the alloy, shortening the service life of the crankshaft.

6. Open flame heating of the piston

Due to the interference fit between the piston and the piston pin, when installing the piston pin, the piston should be heated and expanded first. Some maintenance personnel will directly heat the piston on an open flame, which will cause uneven thermal expansion and contraction of various parts of the piston, leading to deformation. Its service life will also be significantly shortened. Therefore, it should be evenly heated in hot oil to slowly expand.

7. Boil the water tank and add cold water directly

When the water tank is boiling, adding cold water immediately can cause cracking of the cylinder head and cylinder block. Therefore, emergency measures should be taken to stop the operation and allow the engine cooling water to cool down on its own.