As the core equipment in engineering construction, the stability of excavator engine system is very important. However, if the hidden fault of oil water is not handled in time, it will cause the crankshaft and connecting rod deformation to cause engine jitter, and it will cause component fracture to cause the whole machine to be scrapped. This paper analyzes the causes of failure and diagnosis methods from a professional perspective, and provides technical guidance for front-line maintenance personnel.

Five big triggers to watch out for

1. Water plugging corrosion leakage: the water plugging corroded by the coolant for a long time is easy to form through-through rust holes, resulting in cooling water penetrating into the oil pan through the channel, and the sealing of the water plugging should be regularly tested.

2. Oil radiator failure: the damage of the radiator line will make the external coolant invade the lubrication system, especially the cracks of the radiator shell and the aging of the interface.

3. Cylinder liner stress crack: in winter, the use of antifreeze leads to the freezing crack of the cylinder block, or the sharp change in the temperature difference between the cylinder liner and the coolant produces micro-cracks, resulting in the coolant directly into the crankcase.

4. Seal aging: hardening deformation of cylinder liner seal ring is one of the main causes of water inflow, and relevant seals need to be replaced synchronously during engine overhaul.

5. Cylinder pad failure: The failure of the cylinder pad under high temperature and high pressure will break the separation between water and oil, it is recommended to replace the new cylinder pad every time the engine is removed and installed.

Four steps for rapid diagnosis

1. Appearance observation method: the normal oil is transparent brown, the oil will appear milky white turbidity, and the oil pan can be clearly stratified when discharging oil.

2. Coolant detection: open the tank cover to observe the liquid level. If oil flowers are found floating or the coolant is viscous, it can be determined that oil and water are mixed.

3. Dipsmeter detection method: the oil and water emulsification will form white foam in high temperature environment, and the emulsion attachment can be seen when the dipsmeter is extracted, accompanied by the abnormal increase of the oil level of the machine.

4. Pressure test method: use a special detector to pressurize the cooling system, and observe the pressure gauge value mutation to accurately locate the leakage point.

Code for emergency handling

After the oil is found to be in water, it is strictly forbidden to start the engine twice! The three-step disposal process should be implemented immediately: first, drain the deteriorating oil, second, thoroughly clean the oil channel and replace the filter element, and finally, the professional technician uses an endoscope to detect the water in the cylinder. During maintenance, it is necessary to focus on high risk components such as radiator, water blockage and cylinder liner sealing ring. It is recommended to carry out pressure testing of the cooling system every 2000 hours.

Technical experts stress that preventive maintenance is the key to avoid such failures. Maintenance procedures such as freezing point detection of antifreeze liquid, ultrasonic detection of water blockage and hardness test of cylinder liner should be strictly implemented in daily life to reduce the risk of engine water intake from the source and ensure efficient operation of equipment.