MAINTENANCE MANUAL OF GW4D20/GW4D20B TURBOCHARGED DIESEL ENGINES
100
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
(continued)
Phenomenon and Cause of Malfunction
Troubleshooting
High oil
consumption
(1)
Wear
and
damage
of
the
turbocharger sealing ring
(2) Oil leakage at the end of
compressor blades
(3) Looseness of screws at the joint
part of the oil inlet pipe and oil return
hose; damage of the gasket
(4) Low oil quality
(1) Replace the turbocharger assembly.
(2) Overhaul.
(3) Overhaul the oil inlet pipe, oil return hose;
replace the gasket.
(4) Replace the engine oil as specified, it is
recommended to use API CI-4 or better oil
from Mobil Oil Corporation.
Abnormal
sounds
(1) Too much oil dirt in the turbo end air
passage, leading to obvious reduction
of the air flow
(2) Too much oil dirt in the compressor
end, leading to obvious reduction of the
air flow
(3) Excessive wear of the floating
bearing; friction among the turbo, gas
compressor impeller and housing
(1) Clean or replace it.
(2) Clean or replace it.
(3) Replace the turbocharger assembly.
Vibration
caused by
friction
among the
turbo, gas
compressor
impeller and
housing
(1) Foreign materials in
(2) Excessive wear of the floating
bearing
(3) Poor dynamic balance of the turbo
shaft
(1) Clean or replace it.
(2) Replace the turbocharger assembly.
(3) Check, repair or replace it.
Caution:
(1) When the diesel engine is disassembled and reinstalled for troubleshooting, it is strictly forbidden to
let foreign materials enter the air intake and exhaust systems. Since the turbocharger rotor rotates at an
extremely high speed and the clearance between the rotor and the housing is very small, the rotor
operation will be affected and the blades will be damaged as long as foreign materials enter the impeller
despite of the size and the hardness of the foreign materials. When the blades are damaged, the
turbocharger will vibrate abnormally and make noise. Stop the vehicle immediately and overhaul the
turbocharger.
(2) When oil leakage occurs in the turbocharger, do not replace the turbocharger hastily as long as the
impeller of the revolving shaft isn’t rubbing the inner housing and moves smoothly. The turbocharger can
still be used after the oil leakage malfunction is eliminated.
11. Malfunction of the Diesel Engine Oil Supply System
Do not randomly disassemble and reinstall the electronic oil supply system because most parts are
special precision pieces and rarely malfunction; if it is verified that a malfunction does exist, check and
repair it in a professional service station. Check and inspection requires special testing equipment and
special diagnostic apparatus. The model of diagnostic apparatus is KTS 650.Strictly follow the
diagnostic
principle and cautions
during inspection.
