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The Serious Oil Dripping Fault Of Lower Exhaust Is Analyzed As The Blockage Of Drying Tank

Some card users will find that the truck will leak oil on the ground after parking on the ground for a long time. Today we bring you a failure case, which is the case.

Cyclone Oil-Gas Separator Exhibited In 2013 Beijing Engine Exhibition Of Lower Exhaust

The Auman lion 260 Shangchai engine of kayou “Luan Genfa” found that its vehicle oil leakage was serious (Forum original post: strange lower exhaust oil dripping was serious, it turned out that the drying tank was blocked). After doing a test, it was found that the exhaust pipe of the engine leaked air.

Case: Exhaust Oil Dripping

In this case, card friends are not anxious to listen to the suggestions and go to the maintenance plant to replace the four supporting facilities. Instead, after cleaning the oil pan and cylinder block, make preparations and conduct sectional experiments to see where the oil leakage is. During the test, he found some phenomena.

1. The lower exhaust oil drops seriously.

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


3. The valve cover is normal.

Analyze The Reason Why The Drying Tank Is Blocked By The Blow By Of The Air Pump

The engine normally has certain piston ring blowby, and the mixer enters the crankcase during compression, but the damage to the engine is not great. The crankshaft ventilation box device of the engine can improve the problem of engine blowby under normal conditions. The oil-gas separator separates the oil and gas of crankcase blowby. The relatively environmentally friendly closed oil-gas separator sucks the separated gas into the combustion chamber for combustion, and the oil flows into the oil pan through the circuit. The open oil-gas separator directly discharges the separated gas to the atmosphere. At present, the domestic diesel engine basically uses the open arrangement.

The “oil spray” phenomenon in the case will occur in the open oil-gas separator system. If the oil-gas separator is blocked and the pressure in the crankcase is too high, the oil in the oil pan will enter the oil-gas separator through the pipeline and oil return port and eject from the air outlet.

The reasons for the blockage of oil-gas separator are generally as follows:

1. Engine overload. The higher the engine speed and the greater the load, the more mixture will flow into the crankcase, which is easy to cause overload failure of the oil-gas separator. In the forum, many car owners responded that the oil spray was under heavy load, uphill and other working conditions.

2. The clearance is too large. The valve guide and valve clearance of cylinder head are too large (especially when butterfly valve is used for braking).

3. Air compressor blow by. Caused by wear of piston ring of air compressor.

4. The air outlet of the air compressor is blocked, resulting in gas channeling. For example, the air outlet pipe (spiral pipe) of the air compressor is blocked, and the drying tank is blocked.

As the age of the vehicle increases, the gap value of each part will also increase, so the probability of similar situations will be more.

The fourth cause of the accident in this case is the blow by of the compressor pump. The oil and water vapor lead to the blockage of the drying tank, the oil and water vapor resistance of the engine is large, and the gas flows back to the crankcase, resulting in severe oil dripping from the exhaust pipe.

Solution To Oil Channeling Caused By Blockage Of Drying Pipe

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

2. Check the air pump. If the oil channeling is serious, the remedy should be applied to the case.

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 simple methods, you have to spend money to the maintenance station.


Lower exhaust oil leakage is not necessarily a four matching problem. It is not necessary to overhaul the engine and replace the four matching easily. The air pump in this case has problems, but the method to solve the gas channeling of the air pump is to clean the drying tank. It can be seen that the engine is a coordination system, and the oil channeling may not be caused by component failure. When checking the failure, we must observe more and do not make an arbitrary conclusion. Of course, if the air pump is damaged, the air pump assembly should be replaced.

Related Reading:

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