User Manual

1. Inspect the turbine for damage by a foreign object.
If there is damage, determine the source of the
foreign object. Replace the turbocharger. If there is
no damage, go to step 2.
2. Inspect the turbine wheel for the carbon and other
foreign material. Inspect turbine housing (1) for
carbon and foreign material. Replace the
turbocharger, if necessary. If there is no buildup of
carbon or foreign material, go to step 3.
3. Turn the rotating assembly by hand. While you turn
the assembly, push the assembly sideways. The
assembly should turn freely. The turbine wheel
should not rub turbine wheel housing (1). Replace
the turbocharger if the turbine wheel rubs turbine
housing (1). If there is no rubbing or scraping, go
to step 4.
4. Inspect the turbine and turbine housing (1) for oil
leakage. Inspect the turbine and turbine housing
(1) for oil coking. Some oil coking may be cleaned.
Heavy oil coking may require replacement of the
turbocharger. If the oil is coming from the
turbocharger center housing go to step 4.a.
Otherwise go to “Inspection of the Wastegate”.
a. Remove the pipe for the oil drain. Inspect the
drain opening. Inspect the area between the
bearings of the rotating assembly shaft. Look for
the oil sludge. Inspect the oil drain hole for the
oil sludge. Inspect the oil drain line for the oil
sludge. If necessary, clean the drain line.
b. If crankcase pressure is high, or if the oil drain is
restricted, pressure in the center housing may
be greater than the pressure of turbine housing
(1). Oil flow may be forced in the wrong direction
and the oil may not drain. Check the crankcase
pressure and correct any problems.
c. If the oil drain line is damaged, replace the oil
drain line.
d. Check the routing of the oil drain line. Eliminate
any sharp restrictive bends. Make sure that the
oil drain line is not too close to the engine
exhaust manifold.
e. If steps 4.a through 4.d did not reveal the source
of the oil leakage, turbocharger (3) has internal
damage. Replace the turbocharger.
Inspection of the Wastegate
The wastegate actuator controls the amount of
exhaust gas that is allowed to bypass the turbine side
of the turbocharger. This valve then controls the rpm
of the turbocharger.
When the engine operates in conditions of a low
boost (lug), a spring presses against a diaphragm in
the canister. The load on the spring holds the
wastegate closed. The turbocharger can then
operate at maximum performance.
When a boost pressure signal acts against the
diaphragm in the wastegate, the pressure overcomes
the spring and the wastegate actuator will open. The
rpm of the turbocharger becomes limited. The rpm
limitation occurs because a portion of the exhaust
gases bypass the turbine wheel of the turbocharger.
The following levels of boost pressure indicate a
potential problem with the wastegate actuator or
wastegate regulator:
• Too high at full load conditions
• Too low at all lug conditions
The boost pressure controls the maximum rpm of the
turbocharger, because the boost pressure controls
the position of the wastegate. The following factors
also affect the maximum rpm of the turbocharger:
• The engine rating
• The power demand on the engine
• The high idle rpm
• Inlet air restriction
• Exhaust system restriction
Note: Check the operation of the wastegate
regulator. Refer to Troubleshooting, “Solenoid Valve -
Test”.
Check the Wastegate for Proper
Operation
Table 6
Required Tools
Tool
Part
Number
Part Description
QTY
A
21825617
Dial Gauge 1
66 UENR0623-02
Air Inlet and Exhaust System
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