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Shangchai W Series Engine Troubleshooting Guidelines II

Dec. 12, 2017

This is the part two of shangchai W series engine troubleshooting guidelines. We have learned the part one which contains fault mode No. 1 Engine will not start and No. 2 Engine power output low. In this part, we are going to learn the guidelines of No. 3 abnormal noise, No 4 abnormal smoke and No. 5 abnormal oil pressure.

Shangchai W Series Engine Troubleshooting Guidelines II

Please check the below detailed information about troubleshooting guidelines in order to maintain and operate related Shangchai machines carefully..


No 3. Abnormal Noise



  Fault feature


 Possible cause





There is rhythmic and dear metal slapping noise made by in the cylinder.



Too early fuel supply


Check and adjust the fuel injection pump timing.



There is low and non-dear slapping noise in the cylinder.



Too late fuel supply


Check and adjust the fuel injection pump timing.



There Is light and speculate noise, which is clearer during idle running.



Clearance between piston pin and small end bushing of connecting rod is too big.


Check the small end bushings of the connecting rods and replace the connecting  rod(s) if necessary.



There is collision noise from the cylinder block. The noise  would be loader when the speed is increased.



Clearance between piston and cylinder liner is too large.


Check the pistons and liners for wear and make replacement of piston or liner according to wear condition.



There is collision noise in crankshaft case during  running. There is heavy and forceful collision noise when reducing the speed suddenly.



Too large clearance between a  crankshaft pin and connecting  rod bearings due to bearing  wear.


Disassemble and inspect connecting rod bearings. Replace them if necessary.



There is collusion noise made by the shuttle of the crankshaft during idle running.



Too large crankshaft end-play due to wear of the crankshaft thrust bearing leads to the shuttle of the crankshaft.



Check the crankshaft end-play and the wear condition of the thru8t bearing. Replace the thrust bearing if necessary.



There is rhythmic and light slapping noise at cylinder head.


Valve spring broken, push rod bent, tappet sleeve wear or valve damaged.



Replace the damaged parts and adjust the valve clearance according to the process in 5.3.



There is low, uniform and rhythmic slapping noise at cylinder head during running and collision can be felt when nipping the nuts of the cylinder head cover.





Valve collided with piston


Remove the cylinder head cover, find out the collusion cause, and adjust the valve clearance. If necessary. check if wrong piston(s) is used.



There is abnormal noise around gear housing(SC33W in diesel engine rear). collision noise can be heard when reducing speed suddenly.



Too big gear gear due to tooth wear.


Adjust the tooth clearance, and replace the  gear according to the wear condition.



There is noise like “Zhi Zhi” at the cylinder head, which is caused by dry friction.



Lack of tube oil between  rocker-arm adjusting screw and push rod.



Remove the cylinder head cover, and check and find out the cause.



There is rhythmic and louder noise at cylinder head.



Valve clearance too large.


Check and adjust the valve clearance according to the process in 5.3.



There is abnormal collision noise from the turbocharger.



Poor lubrication due to blocked oil passage leads to the blade(s) bent because of bearing wear.



Disassemble and check whether the bearing is worn out and the blade(s) is bent. Make replacement if necessary. Clean the oil inlet and outlet passages to ensure smooth oil flow.



 Heavy combustion noise.




(1) Poor fuel quality


(2) Fuel pump fault


Discharge the fuel in the tank and add clean fuel specified in the manual. Add replace the fuel filter.


Determine the fuel pump problem by making one cylinder stop working at a time or by testing the fuel pump on a pump test bench to check fuel supply for fuel flow or evenness.



Serious engine vibration



(1) injector(s) or fuel injection pump plunger(s) does not work.


(2) Looseness of the nuts fixing the engine to the equipment.


(3) Offset of the central lines of the engine and propeller shaft (marine application)



Check the injector(s) or the fuel pump plunger and barrel assembly(s). replace the injector(s) or fuel injection pump if required.


Tighten the nuts.


Make the central lines in alignment.


No. 4 Abnormal Smoke



Fault Feature


Possible Cause
















Black smoke



1) The engine load exceeds the defined value.


2) Uneven fuel supply of each cylinder.


3) Wrong valve clearance and bad seal of valve lead to leakage at valve and bad combustion.


4) Too late fuel supply due to too small injection advace angle leads to part of fuel burning in the exhaust manifold.


5) Poor fuel atomization.


6) Insufficient inlet air due to block of air filter or inlet pipe, or the compressor housing too dirty.


7) The elastic gas seal ring of the turbocharger is burn or wear. There is leakage at the connections of the turbine.


8) Bad wear of piston rings.



Reduce the load to the defined range.


Let a professional serviceman adjust the fuel injection pump.

Adjust the valve clearance, check valve facing condition and eliminate the defects.


Check and adjust the fuel injection pump timing.


Let a professional serviceman check injector(s) for fuel atomization.


Clean and remove the dust. Replace the filter element if necessary.


Let a professional serviceman check the seal ring, and replace it if necessary. And tighten all connecting bolts of the turbine.


Replace the piston rings.


Fault feature



Possible Cause













White smoke


(1) bad fuel atomization with fuel dripping and too low injection pressure.


(2) The fuel in some cylinder cannot burn during engine start-up (especially in winter)

(3) Too much water in the fuel.


(4) Coolant entering cylinder due to crack of the cylinder head.



Let a professional serviceman check the fuel injector nozzle assembly(s), maintain or replace the assembly(s), and regulate the injection pressure to the defined valve.


Increase speed and load, and keep the engine running at high speed and load for longer time.


Remove the water in the fuel.

Check the exhaust pipe for water condensation and replace the cylinder head if necessary.















Blue smoke


(1) poor air intake due to the block of the air filter.


(2) Lube oil in the combustion chamber resulting from seizure or much wear or insufficient elasticity of piston ring, or incorrect ring chamfer direction due to wrong installation.


(3) Large clearance between piston and cylinder liner due to long time low-load running (less than 40% of rated power) facilitate3d oil entering the combustion chambers.


(4) Too much lube oil in oil sump.


(5) Damage of the oil seal of the turbocharger leads to lube oil into the intake manifold.




Replace the air filter


Remove and check the piston rings, make replacement if necessary.


Increase load to a proper degree, and choose a proper application power.


Adjust tube oil level near high level mark in the dipstick.


Check the intake manifold for oil trace, check or replace the turbocharger when necessary.

No. 5 Abnormal Oil Pressure



Fault feature


Possible cause












Oil pressure decreases and it cannot be corrected by the pressure regulating valve and the reading of the pressure gauge fluctuates


(1) oil leak at the oil pipeline


(2) Air in the oil pump, or insufficient oil in oil pan.


(3) Block of the oil cooler or oil filter, fracture of the cooler core, or oil leak at the oil seal gasket.


(4) Bad oil leak at the crankshaft bearing(s), crankshaft front and rear oil seals, camshaft bearing(s).


(5) Fuel in oil.


(6) The piston cooling jet(s) is not installed.


(7) Oil is diluted.


Check and tighten the buts

Add oil to the defined level.


Clean the oil cooler, and replace damaged parts and oil filter if necessary.


Check each part, and replace those whose wear exceeds the defined valve.


Find out the location of fuel entering oil and make necessary repair. Change the oil and oil filter.


Install the missing piston cooling jet(s)


Find the cause and change the oil and oil filter.








No oil pressure, the indicator of the pressure gauge keeps standstill.



(1) The oil pressure gauge is damaged.


(2) Block of the oil duct


(3) Serious damage or seizure of the oil pump due to incorrect assembly


(4) Oil pressure regulating valve does not work due to the damage of its spring.



Make replacement.


Clean the oil duct


Reinstall the oil pump and replace it if required.


Replace the regulating valve.


For other user manual details about Shangchai W series engine:

Task And Methods of Shangchai W Series Diesel Engine Maintenance

Changing Coolant And Cleaning Cooling System of Shangchai Engine

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