Daewoo DE12 Shop Manual page 142

4.4.5. Walk-around check and servicing
As the condition of turbocharger depends greatly on how well the engine is serviced, it is very
important to maintain the engine in accordance with the specified maintenance procedure.
1) Intake system
Pay particular attention to the air cleaner when servicing the intake system.
In the case of wet-type air cleaner, if the level of oil surface is lower than specified, cleaning
effect is poor; if too high, the cleaner draws in oil to foul the case.
Especially, if the rotor is fouled, the sophisticatedly-tuned balance is broken to create vibration
and to cause seizure and unusual wear to the bearing. Therefore, it is very important to use a
good quality air cleaner all the time.
In the case of dry-type air cleaner, it is essential to clean it according to the readings on the
dust indicator to reduce intake resistance as much as possible.
2) Exhaust system
Pay particular attention to prevent gas leaks and seizure when servicing the exhaust system
because leakage of exhaust gas from discharge pipes, turbocharger fixing portions, etc. low-
ers charging effect.
As such components as turbine chamber that becomes red-hot during operation use heat
resisting steel nuts, do not interchange these nuts with ordinary steel nuts. In addition, apply
anti-seizure coating to fixing nuts on the portions as designated.
3) Fuel system
If the full load stopper regulating the maximum injection volume and the maximum speed stop-
per regulating the maximum speed in the fuel injection pump are adjusted without using a
pump tester, the turbocharger rotates at excessively rapid speed and may suffer damage.
Besides it, if spray pattern from the fuel injection nozzles is bad or the injection timing is incor-
rect, temperature of exhaust gas rises up to affect the turbocharger adversely. To avoid such
trouble, be sure to make a nozzle test.
4) Lubricating system
Pay particular attention to oil quality and oil filter change intervals when servicing the lubricat-
ing system. Deteriorated engine oil affects adversely not only the engine but also the tur-
bocharger. Suggested engine oils for the turbocharger-mounted engine are as follows:
(1) During hot season: SAE 30(CD grade), DE12TIS SAE 30(CG grade)
(2) During cold season: SAE 10W(CD grade), DE12TIS SAE 10W(CG grade)
(3) During both seasons: SAE 10W~30(CD grade), DE12TIS SAE 10W~30(CG grade)
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