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Possible inadequate cooling or high oil viscosity.

Solution: Improve ventilation, use correct viscosity oil.

Reasons from the piston group
1. The piston ring gap is too small. If the opening gap, side gap or back gap of the piston ring is too small, the piston ring will be stuck due to heat expansion when the engine is working, and it will be pressed tightly against the cylinder wall, or the piston ring will be broken, which can easily pull out grooves on the cylinder wall.
2. The piston pin is out. Because the piston pin retaining ring is not installed or falls off or breaks, the piston pin will be out during movement, which can easily damage the inner wall of the cylinder and cause the cylinder to blow into the crankcase.
3. The piston cylinder gap is too small or too large. If the piston material is poor, the manufacturing size error is too large, or the piston is deformed after the piston pin is assembled, the matching gap between the piston and the cylinder is too small, and the piston is stuck after heat expansion, which will then damage the cylinder wall.
4. The piston ring is seriously carbonized. Excessive carbon deposits cause the piston ring to stick or bite in the ring groove. At the same time, carbon deposits are a hard abrasive that will grind into longitudinal grooves on the cylinder wall.
5. The piston is seriously off-cylinder. Due to the bending and twisting of the connecting rod, the parallelism and coaxiality deviations of the connecting rod journal, main journal, and piston pin seat are too large, causing the piston to be significantly off-cylinder, which will accelerate the wear of the piston ring, piston and cylinder wall and destroy the formation of the oil film.

Reasons for cylinder sleeves
1. The roundness and cylindricality tolerances of the cylinder sleeves exceed the allowable range, which greatly reduces the sealing of the piston and cylinder sleeves. The high-temperature gas in the cylinder flows down, destroying the oil film between the piston and the cylinder wall, and then causing cylinder pulling.
2. The cylinder sleeve is deformed during the assembly process. For example: the protrusion of the upper end surface of the cylinder sleeve is too large, and the cylinder sleeve is deformed after the cylinder head is installed; the cylinder sleeve water blocking ring is too thick, and the cylinder sleeve is deformed after being pressed into the body, which can easily cause cylinder pulling.

Reasons for use:
1. Whether the size of the cylinder sleeve used during assembly does not match the cylinder body and piston.
2. The air filter is not sealed, which makes the filtering effect worse. Dust, sand and other impurities in the air are sucked into the cylinder, forming abrasive wear. Tests show that if a few grams of dust are sucked in every day, the wear of the cylinder liner will increase by more than 10 times.

Blue smoke when starting a cold car: It is normal for a cold car to emit blue smoke and disappear after the car is heated, because a small amount of oil will invade the engine combustion chamber after the shutdown. Continuous blue smoke after starting:

1. The diesel filter is clogged, check whether the oil type is correct;

2. The engine piston ring and valve oil seal are worn, affecting the oil in the intake or exhaust pipe, which causes the excavator to emit blue smoke;

3. The clearance between the piston and the cylinder liner is too large, causing blue smoke;

Possible loose installation, unbalanced pump components, or cavitation.

Solution: Tighten installation, balance pump components, check and eliminate cavitation sources.

When the battery liquid specific gravity is lower than 1.15 or the single cell voltage is lower than 1.7V (V), or when changing seasons for maintenance, it should be removed for recharging and the liquid specific gravity should be adjusted. If it needs to be parked for a long time, it should be fully charged and stored, and recharged once a month. If it needs to be stored for a long time, it should be fully charged, all the liquid should be poured out, and the filling port should be sealed for storage. When it needs to be used, re-add the electrolyte that meets the requirements.