The reason for the engine oil leakage failure is not necessarily to replace the four sets?

Symptoms

Clean the oil sump cylinder and make preparations. Sectional experiments are performed to see where the oil is leaking. During the test, it was found that:

1. The lower exhaust engine oil drips seriously.

2. The lower exhaust is not large, and the smoke color of the exhaust pipe is normal.

3. The valve cover is normal.

Failure Cause Analysis

Although the engine is normal, there is still a certain amount of blow-by of the piston rings. The mixture gas enters the crankcase during the compression process, but it does not cause much damage to the engine. The crankshaft ventilation box device of the engine can improve the problem of engine blow-by under normal conditions.

The oil-gas separator separates the oil and gas of crankcase blow-by. The relatively environmentally friendly closed oil-gas separator sucks the separated gas into the combustion chamber for combustion, while the oil flows into the oil pan through the circuit. The open-type oil-gas separator directly discharges the separated gas to the atmosphere. At present, domestic diesel engines basically use an open-type arrangement.

The phenomenon of “spraying engine oil” will appear in the open oil-gas separator system. If the oil-air separator is clogged and the pressure in the crankcase is too high, the oil in the oil pan will enter the oil-air separator through the pipeline and the oil return port, and will be sprayed out from the air outlet.

The reasons for the clogging of the oil and gas separator are generally as follows:

1. The engine is overloaded.

The higher the engine speed and the greater the load, the more the mixture will enter the crankcase, which will easily cause the overload failure of the oil-gas separator.

2. The gap is too large.

The cylinder head valve guide and valve clearance values are too large (especially when using butterfly valve brakes).

3. Bleeding air from the air compressor.

Caused by worn air compressor piston rings. The air outlet of the air compressor is blocked, resulting in gas blow-by. For example, the air compressor outlet pipe is blocked, the drying tank is blocked, etc. As the age of the engine increases, the gap value of each part will also increase, so the probability of such a situation will increase.

The reason for this failure case is the fourth, that is, air blowing from the air pump of the compressor, oil and water vapor causing dirty things to block the drying tank, oil and water vapor resistance from the engine, and the gas flowing back to the crankcase, resulting in severe oil dripping from the exhaust pipe.

Solution

1. Check whether the vent is blocked, if it is blocked, remove the interface for cleaning.

2. Check the air pump. If the oil leakage is serious, you should prescribe the right medicine.

3. Check whether the drying tank is blocked, if it is blocked, clean the drying tank or replace it with a new one. If you still can’t solve the oil leakage problem through these simple methods, you have to spend money to repair the station.

The oil leakage of the lower exhaust is not necessarily a four-pack problem, and there is no need to easily overhaul the engine and replace the four-pack. In this case, there was a problem with the air pump that had a problem, but the solution to the blow-by of the air pump was to clean the drying tank. It can be seen that the engine is a coordinated system, and the oil leakage may not be caused by component failures. When checking the faults, you must observe more and do not draw conclusions arbitrarily. Of course, if the air pump is really damaged, the air pump assembly should be replaced.

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