In the use of automobiles, oil leakage often occurs, which will directly affect the technical performance of automobiles, resulting in the waste of lubricants and fuel, power consumption, impact on vehicle cleanliness and environmental pollution. Because of oil leakage and the reduction of lubricating oil in the machine, the lubrication of the parts is poor and the cooling is insufficient, which will cause the early damage of the parts and even leave the hidden danger of accidents.

I. Main Causes of Oil Leakage in Common Vehicles

1. The quality, material or process of products (accessories) are not good; there are problems in structural design.

2. Improper assembly speed, unclean surface, damaged liner, displacement or not in accordance with the operating procedures and specifications for installation.

3. Uneven screw force of fastening nut, broken thread or loose and falling off lead to work failure.

4. After long-term use, the wear of sealing materials is over-limited, aging, deterioration, deformation and failure.

5. Excessive lubricant addition, excessive oil surface or wrong oil products.

6. Components (edge covers, thin-walled parts) are deformed and damaged on the jointing surface, which causes the oil to seep out.

7. After the blockage of the air plug and one-way valve, the oil leakage in the weak sealing place will often occur due to the effect of the pressure difference between the inside and outside of the case.

II. Measures to Prevent Oil Leakage in Vehicles

1. Pay attention to the role of liner. The gaskets between the parts of automobile stationary position (such as joint end face, end cap, shell, cover pad, plane enamel cover plate, etc.) play a leak-proof sealing role. If the material, manufacturing quality and installation do not meet the technical specifications, it will not play a sealing and leak-proof role, or even accidents. For example, the oil pan or valve cover is not easy to compact because of its large contact area, resulting in oil leakage. When disassembling and assembling, pay attention to proper placement, carefully check, and assemble according to the specifications.

2. All kinds of fastening nuts on the vehicle should be tightened according to the prescribed torque. Over-loosening and not tightening the liner will leak; over-tightening will make the metal around the screw hole protrude or screw the thread to slip and cause oil leakage. In addition, if the oil discharging screw plug of the oil pan is not tightened or loosened off, it is easy to cause oil loss, and then a damage accident of "burning tile and holding axle" occurs.

3. Replace the invalid oil seal in time. Many moving parts (such as oil seals and O-rings) on the vehicle will throw oil due to improper installation, the journal and the edge of the oil seals are not concentric, and the yaw. Some oil seals will lose elasticity due to ageing of rubber when they are used too long. The leakage should be updated in time.

4. Excessive wear and tear (such as piston and cylinder) will occur when automobile parts are used too long, which will lead to high-pressure gas in combustion chamber entering crankcase and forcing oil leakage. Therefore, when the exhaust gas channeling from the oil filling cover is serious, the wear parts should be repaired or replaced as soon as possible.

5. Avoid blocking of one-way valves and ventilation valves. As a result, the temperature in the case rises, the oil and gas fills the whole space and can not be discharged into the canal, thus increasing the pressure in the case and increasing the consumption of lubricating oil and shortening the replacement period. After the blockage of the engine ventilation system, the motion resistance of the piston is increased and the fuel consumption is increased. Owing to the effect of pressure difference between inside and outside of the case, oil leakage at weak seals is often caused. Therefore, regular inspection, dredging and cleaning of vehicles are needed.

6. Solve all kinds of tubing joint seals properly. Vehicle coupling nuts are often disassembled and assembled, easy to slip thread break and loosen; the accuracy of horn mouth of two joints is poor, and the center line of two cones does not coincide and contact is poor; different taper does not coincide, which will cause oil seepage. Replace the joint nut and solve the conical seal by grinding, so that the nut can be pressed tightly and the seal can be solved.

7. Avoid oil throwing from hub. Excessive lubrication grease in hub bearings and cavity, improper oil package, poor quality and aging failure, excessive hub temperature caused by frequent braking, loosening axle nuts and so on will cause hub oil rejection. Therefore, it is useful to use "cavity lubrication method", dredge ventilation holes, strictly select high-quality accessories, and assemble and high-speed according to process specifications.

3. Key Points of Vehicle Maintenance and Repair

Assembling under extremely clean conditions, no bump, scratch, burr and other attachments on the working surface of the parts; rigorous operating procedures, seals should be installed correctly to prevent out-of-place deformability; grasp the performance specifications and use requirements of seals, timely replacement of failed parts; for thin-walled parts of edge cover, sheet metal cold is used to correct; easy-to-wear parts of shaft hole can be used gold. It belongs to spray plating, welding repair, glue, mechanical processing and other processes to achieve the original size; using sealant as far as possible, and replacing paint when necessary can achieve the ideal sealing effect; breaking and loosening of nuts should be repaired or replaced, and screwed to the specified torsion; rubber seals should be carefully checked before assembly; special tools should be used to press fittings to avoid knocking deformation; and injection and moistening according to regulations. Slip grease, regular cleaning and dredging vents and one-way valves. As long as the above points are achieved, the problem of vehicle oil leakage can be completely eradicated.