Automobile Encyclopedia: Does the engine compartment need cleaning?

Automobile Encyclopedia: Does the engine compartment need cleaning?

Assume that the engine compartment must be cleaned.

Not suitable for washing with water.

There is more than one engine in the engine compartment of a car. Don't think that avoiding the engine air intake won't hurt the car! The core assembly in the engine room includes: gearbox, steering gear, computer board, battery, fuse box, etc. Among them, in order to prevent the internal pressurization of the gearbox from damaging the strength of the shell due to long-term high-speed operation, an exhaust hole will be left on the shell to realize constant pressure; Although there will be a waterproof cap on the exhaust hole, the flushing with a high-pressure water gun cannot guarantee that water will never enter. Once water enters, it will cause the emulsification and wear of transmission oil to increase.

Most automobile steering systems use "electronic power assist", and the core structure includes a power assist motor and an electronic control module. What happens if high-pressure water is charged into the electronic control module? Secondly, the computer version of ECU is the "brain" of the whole vehicle, and the operation of engine, ESP system and various control systems all need ECU control; However, this computer version does not have a high standard of waterproof ability. Many cars will break down after wading without water because the computer board is short-circuited and burned out.

Just splashing water won't short-circuit the battery, but the fuse will short-circuit! The car fuse box has one set in the car and one set in the engine compartment; Although the fuse box will have a cover, the gap is wide enough.

According to the actual measurement, the engine compartment was washed by the high-pressure water gun, which led to abnormal configuration functions of the vehicle, including some equipment failures. Therefore, in order to ensure the safe driving of vehicles, it is really not allowed to use high-pressure water guns to wash the engine compartment at will-the pressure of water guns used in car wash shops is very high.

Hot cars should not be washed with water.

The fuel truck can reach "hot state" after driving for several kilometers. The temperature of the engine and antifreeze coolant can be as high as 100 degrees Celsius, and the temperature of the front radiator water tank is also very high. Key points: There is no doubt that the materials of car body and water tank are steel or alloy, and these materials will inevitably "expand when heated and contract when cooled". In the hot car state, if it is washed directly with warm water (this is low temperature to offset the body temperature problem), it is equivalent to cooling the steel quickly; However, the position of splashing water will not be very balanced, which will inevitably lead to excessive cold shrinkage of steel in some areas, resulting in cracks in steel due to uneven stress.

For recent well-known cases, please refer to "Toyota Motor Oil Emulsification &; In the case of "increase", both domestic cars and American cars equipped with some batches of NA models have the problem that the engine oil is emulsified first and then increased. The reason is that unqualified steel leads to cracks in the cylinder head during slow thermal expansion and cold contraction, which leads to poor sealing performance of the cylinder head and leakage of antifreeze coolant mixed with engine oil. This shows how serious the damage caused by cleaning the engine compartment with cold water is. Cleaning the engine compartment must wait until the temperature drops.

If there is no cleanliness, there is really no need to clean the engine compartment of the car. If you want to clean it, you should refer to the above method. However, it is the most reasonable to use high-pressure gas to clean the car during normal maintenance, because gas will not cause short circuit of electronic equipment; Moreover, every auto repair shop will have an air pump. Cleaning the engine room is basically a bonus business, so there is no need to bother cleaning the engine room.