MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
94
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
to the noise characteristics and combining the structure principle.
Attention:
It is strictly prohibited that the engine continues operating in case of abnormal noise, stop
running immediately if abnormal noise appears, check and eliminate the malfunction, then continue to
work.
Phenomenon and Cause of Malfunction
Troubleshooting
(1) Malfunction in the fuel supply system
(1) See Subsection 11 of this chapter for relevant
troubleshooting
of
―engine
knocking‖
in
malfunctions in the fuel supply system (see Page
86 ~ 88)
(2) Slight but sharp noise now and then from the
engine, and such noise is especially clear during
idling, and sharper when you suddenly step on the
gas.
(2) Replace the bush of the connecting rod small
end, and make it within the specified clearance
scope.
(3) Excessive clearance between the piston and
the valve, knocking noise from the outside of the
engine body during running, and such noise
intensifies when the rotation speed increases.
(3) Replace the piston and piston ring
(4) Excessive matching clearance between the
connecting rod bearing bush and the main bearing
bush due to too much wearing, clashing noise from
the engine parts at the running crankshaft, heavy
and strong knocking noise during abrupt
deceleration.
(4) Remove and check the connecting rod bearing
bush, the main bearing bush, and replace them if
necessary, and keep them within the specified
matching clearance.
(5) The valve clashing with the piston; heavy, even
and rhythmed knocking noise from the cylinder
head during running.
(5) Find out the cause; check the valve timing;
examine and repair the relevant parts.
