1, the piston ring is not tightly sealed, and the oil enters the cylinder from the gap between the piston and the cylinder wall for combustion (blue smoke).
2. The valve guide and oil seal are worn, and the engine oil enters the cylinder for combustion (blue smoke) or enters the exhaust manifold for combustion and discharge (white smoke).
3, turbocharger rotor wear, oil into the intake combustion (blue smoke) or into the exhaust pipe discharge (white smoke).
4, the cylinder seal is lax, resulting in excessive ventilation in the crankcase (cylinder pulling or piston ring wear), and the splashed oil is discharged from the engine through the crankcase ventilation device or sucked into the air inlet for combustion.
5. External leakage, including crankshaft front and rear oil seals, valve chamber gaskets, oil pan gaskets, oil radiator and other parts.
After inspection, there is no strain trace on the cylinder wall, and the piston ring wear is within the normal range. This is not the problem.
When the engine cylinder wall is disassembled and the cylinder head is inspected, there is no abnormality in the valve oil seal and excessive wear of the valve guide. This is not a problem.
Check it again to remove the root cause. Check the engine again and find that there is something wrong with the power steering oil pot. It is oily outside, like spilled oil. The color of oil stains outside the oil pot is not the color of hydraulic oil (the normal color of semi-hydraulic oil is light yellow or pink), but black and carbon deposit.
Found the problem of the power steering hydraulic pipeline, and the oil ran into the power steering hydraulic pipeline! Only the power steering pump is connected to the engine in the whole power steering system, so this is the problem.