There should be the following aspects:

1. There is diesel oil in the intake pipe. Generally, there is a problem with the flame preheating device;

2. There is oil in the intake pipe, which may be the oil leakage of the supercharger, or the outlet pipe of the oil separator is connected to the intake pipe of the supercharger, or the oil-gas separator is blocked, so that the oil enters the intake pipe through the supercharger;

3. There is diesel oil in the exhaust pipe. Generally, the fuel injector is faulty;

4. There is oil in the exhaust pipe, which may be:

A valve sealing sleeve fails;

B. the piston ring and cylinder liner are seriously worn;

C) oil leakage of supercharger;

D diesel engine runs at low speed for a long time or in winter

According to the above, we can repair or replace the corresponding parts as appropriate to solve the problem of oil in the inlet and exhaust pipes of Weifang Weichai diesel engine.