Dodge Dakota (R1). Manual — part 551
The turbocharger assembly consists of four (4)
major component systems (Fig. 1) (Fig. 2):
• Turbine section
• Compressor section
• Bearing housing
• Wastegate
OPERATION
Exhaust gas pressure and energy drive the tur-
bine, which in turn drives a centrifugal compressor
that compresses the inlet air, and forces the air into
the engine through the charge air cooler and plumb-
ing. Since heat is a by-product of this compression,
the air must pass through a charge air cooler to cool
the incoming air and maintain power and efficiency.
Increasing air flow to the engine provides:
• Improved engine performance
• Lower exhaust smoke density
• Improved operating economy
• Altitude compensation
• Noise reduction.
The turbocharger also uses a wastegate (Fig. 3),
which regulates intake manifold air pressure and
prevents over boosting at high engine speeds. When
the wastegate valve is closed, all of the exhaust gases
flow through the turbine wheel. As the intake mani-
fold pressure increases, the wastegate actuator opens
the valve, diverting some of the exhaust gases away
from the turbine wheel. This limits turbine shaft
speed and air output from the impeller.
The turbocharger is lubricated by engine oil that is
pressurized, cooled, and filtered. The oil is delivered
to the turbocharger by a supply line that is tapped
into the oil filter head. The oil travels into the bear-
ing housing, where it lubricates the shaft and bear-
ings (Fig. 4). A return pipe at the bottom of the
bearing housing, routes the engine oil back to the
crankcase.
Fig. 1 Turbocharger Operation
1 - TURBINE SECTION
2 - EXHAUST GAS
3 - BEARING HOUSING
4 - COMPRESSOR SECTION
5 - INLET AIR
6 - COMPRESSED AIR TO ENGINE
7 - EXHAUST GAS
8 - EXHAUST GAS TO EXHAUST PIPE
Fig. 2 Turbocharger Wastegate Actuator
1 - TURBOCHARGER
2 - DIAPHRAM
3 - WASTE GATE ACTUATOR
11a - 2
EXHAUST SYSTEM AND TURBOCHARGER
R1
TURBOCHARGER SYSTEM (Continued)
The most common turbocharger failure is bearing
failure related to repeated hot shutdowns with inad-
equate “cool-down” periods. A sudden engine shut
down after prolonged operation will result in the
transfer of heat from the turbine section of the tur-
bocharger to the bearing housing. This causes the oil
to overheat and break down, which causes bearing
and shaft damage the next time the vehicle is
started.
Letting the engine idle after extended operation
allows the turbine housing to cool to normal operat-
ing temperature. The following chart should be used
as a guide in determining the amount of engine idle
time required to sufficiently cool down the turbo-
charger before shut down, depending upon the type
of driving and the amount of cargo.
TURBOCHARGER
(
COOL DOWN
(
CHART
Driving
Load
Turbo-
charger
Idle Time
(in minutes)
Condition
Temper-
ature
Before Shut
Down
Stop & Go
Empty
Cool
Less than 1
Stop & Go
Medium
Warm
1
Highway
Speeds
Medium
Warm
2
City Traffic
Max.
GCWR
Warm
3
Highway
Speeds
Max.
GCWR
Warm
4
Uphill Grade
Max.
GCWR
Hot
5
Fig. 3 Wastegate Operation
1 - SIGNAL LINE
2 - EXHAUST BYPASS VALVE
3 - WASTEGATE
4 - EXHAUST
5 - TURBINE
6 - EXHAUST BYPASS VALVE
7 - WASTEGATE
8 - EXHAUST
9 - TURBINE
10 - SIGNAL LINE
Fig. 4 Turbocharger Oil Supply and Drain
1 - BEARINGS
2 - OIL SUPPLY
3 - OIL RETURN
R1
EXHAUST SYSTEM AND TURBOCHARGER
11a - 3
TURBOCHARGER SYSTEM (Continued)
EXHAUST MANIFOLD AND
TURBOCHARGER
REMOVAL
(1) Disconnect the negative battery cable.
(2) Remove both of the wiper arms from the vehi-
cle. Refer to Group 8K, Wiper and Washer Systems
for the procedure.
(3) Raise the vehicle on the hoist.
(4) Remove the lower front splash shield.
(5) Drain the cooling system (Refer to 7 - COOL-
ING - STANDARD PROCEDURE).
(6) Remove the oil return line from the turbo-
charger (Fig. 5).
(7) Lower the vehicle on the hoist.
(8) Remove the cowl grille (Fig. 6) (Refer to 23 -
BODY/EXTERIOR/COWL GRILLE - REMOVAL).
(9) Disconnect the EGR solenoid electrical connec-
tor (Fig. 7).
(10) Disconnect the EGR solenoid vacuum lines
(Fig. 7).
(11) Disconnect the coolant level sensor electrical
connector (Fig. 7).
(12) Remove the coolant reservoir retaining bolts
from inside the cowl panel.
Fig. 5 Turbocharger Oil Return Line Position
1 - STARTER MOTOR HEATSHIELD
2 - TURBOCHARGER OIL RETURN LINE
3 - RIGHT ENGINE MOUNT RETAINING NUTS
4 - STARTER MOTOR SUPPORT BRACKET
5 - STARTER MOTOR
Fig. 6 Cowl Grille
1 - PUSHPINS
2 - COWL GRILLE RETAINING NUTS
3 - PUSHPINS
4 - COWL GRILLE
Fig. 7 Coolant Reservoir Position & Orientation
1 - EGR SOLENOID
2 - COOLANT RESERVOIR RETAINING BOLTS
3 - COOLANT OVERFLOW HOSES
4 - COOLANT LEVEL SENSOR
5 - COOLANT RESERVOIR
6 - COOLANT SUPPLY HOSES
11a - 4
EXHAUST SYSTEM AND TURBOCHARGER
R1
(13) Disconnect the coolant supply hoses from the
coolant reservoir (Fig. 7).
(14) Remove the coolant reservoir from the vehicle.
(15) Disconnect the air intake hose from the turbo-
charger and remove the air cleaner assembly
(16) Disconnect the intercooler outlet hose at the
intake manifold.
(17) Disconnect the intercooler inlet hose at the
turbocharger.
(18) Remove the EGR valve support bracket from
the exhaust manifold heatshield.
(19) Disconnect the EGR tube at the exhaust man-
ifold
(20) Remove the intake manifold elbow retaining
bolts and remove the EGR valve and intake elbow as
an assembly.
(21) Remove the exhaust manifold heatshield.
(22) Remove the turbocharger oil supply line from
the turbocharger.
(23) Remove the exhaust inlet pipe retaining bolts
from the turbocharger.
(24) Remove the (8) exhaust manifold retaining
bolts and remove the turbo and manifold assembly
from the vehicle.
(25) Place the assembly in a vice to remove the (3)
exhaust manifold to turbocharger retaining nuts.
CLEANING
All old gaskets should be inspected for any tears or
signs of prior leakage. If any gaskets show such indi-
cations, they should be replaced with new gaskets.
All gasket mating surfaces must be cleaned of old
gasket material to produce a smooth and dirt free
sealing surface for the new gasket.
INSTALLATION
CAUTION: The turbocharger is a precision piece of
equipment and should only be repaired by an
authorized
facility.
Disassembly
is
not
recom-
mended, as engine / turbo failure could result.
(1) Install the turbocharger on the exhaust mani-
fold. Torque the retaining nuts to 32 N·m (23 ft. lbs.).
(2) Position the manifold and turbo assembly on
the exhaust.
(3) Install the (8) exhaust manifold retaining nuts.
Torque the nuts to 32 N·m (23 ft. lbs.).
(4) Install the exhaust inlet pipe retaining bolts in
the turbocharger. Torque bolts to 32 N·m (23 ft. lbs.).
(5) Install the exhaust manifold heatshield. Torque
retaining bolts to 11 N·m (97 in. lbs.).
(6) Install the intake manifold elbow and EGR
valve as an assembly. Torque intake elbow bolts to
27 N·m (20 ft. lbs.).
(7) Connect the EGR tube at the exhaust manifold.
Torque nut to 40 N·m (30 ft. lbs.).
(8) Install the EGR valve support bracket on the
exhaust manifold heatshield. Torque bolts to 11 N·m
(97 in. lbs.).
(9) Connect the intercooler inlet hose on the turbo-
charger.
(10) Connect the intercooler outlet hose on the
intake manifold.
(11) Connect the air intake hose on the turbo-
charger and install the air cleaner assembly
(12) Install the coolant reservoir in the vehicle and
connect the coolant supply hose (Fig. 8). Torque res-
ervoir bolts to 11 N·m (97 in. lbs.).
(13) Connect the coolant level sensor electrical con-
nector (Fig. 8).
(14) Connect
the
EGR
solenoid
vacuum
lines
(Fig. 8).
(15) Connect the EGR solenoid electrical connector
(Fig. 8).
(16) Install the coolant supply hose on the water
manifold (Fig. 8).
(17) Install the coolant overflow hose on the cool-
ant reservoir (Fig. 8).
Fig. 8 Coolant Reservoir Position & Orientation
1 - EGR SOLENOID
2 - COOLANT RESERVOIR RETAINING BOLTS
3 - COOLANT OVERFLOW HOSES
4 - COOLANT LEVEL SENSOR
5 - COOLANT RESERVOIR
6 - COOLANT SUPPLY HOSES
R1
EXHAUST SYSTEM AND TURBOCHARGER
11a - 5
EXHAUST MANIFOLD AND TURBOCHARGER (Continued)
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