2004 DAEWOO LACETTI radiator

1D – 18IENGINE COOLING
DAEWOO V–121 BL4
GENERAL DESCRIPTION
AND SYSTEM OPERATION
GENERAL DESCRIPTION
The cooling system maintains the engine temperature at
an efficient level during all engine operating conditions.
When the engine is cold, the cooling system cools the en-
gine slowly or not at all. This slow cooling of the engine al-
lows the engine to warm up quickly.
The cooling system includes a radiator and recovery sub-
system, cooling fans, a thermostat and housing, a coolant
pump, and a coolant pump drive belt. The timing belt
drives the coolant pump.
All components must function properly in order for the
cooling system to operate. The coolant pump draws the
coolant from the radiator. The coolant then circulates
through water jackets in the engine block, the intake man-
ifold, and the cylinder head. When the coolant reaches the
operating temperature of the thermostat, the thermostat
opens. The coolant then goes back to the radiator where
it cools.
This system directs some coolant through the hoses to the
heater core. This provides for heating and defrosting. The
surge tank is connected to the radiator to recover the cool-
ant displaced by expansion from the high temperatures.
The surge tank maintains the correct coolant level.
The cooling system for this vehicle has no radiator cap or
filler neck. The coolant is added to the cooling system
through the surge tank.
RADIATOR
This vehicle has a lightweight tube–and–fin aluminum ra-
diator. Plastic tanks are mounted on the right and the left
sides of the radiator core.
On vehicles equipped with automatic transaxles, the
transaxle fluid cooler lines run through the left radiator
tank. A radiator drain cock is on this radiator.
To drain the cooling system, open the drain cock.
SURGE TANK
The surge tank is a transparent plastic reservoir, similar to
the windshield washer reservoir.
The surge tank is connected to the radiator by a hose and
to the engine cooling system by another hose. As the ve-
hicle is driven, the engine coolant heats and expands. The
portion of the engine coolant displaced by this expansion
flows from the radiator and the engine into the surge tank.
The air trapped in the radiator and the engine is degassed
into the surge tank.When the engine stops, the engine coolant cools and con-
tracts. The displaced engine coolant is then drawn back
into the radiator and the engine. This keeps the radiator
filled with the coolant to the desired level at all times and
increases the cooling efficiency.
Maintain the coolant level between the MIN and the MAX
marks on the surge tank when the system is cold.
WATER PUMP
The belt–driven centrifugal water pump consists of an im-
peller, a drive shaft, and a belt pulley. The water pump is
mounted on the front of the transverse–mounted engine,
and is driven by the timing belt.
The impeller is supported by a completely sealed bearing.
The water pump is serviced as an assembly and, there-
fore, cannot be disassembled.
THERMOSTAT
A wax pellet–type thermostat controls the flow of the en-
gine coolant through the engine cooling system. The ther-
mostat is mounted in the thermostat housing to the front
of the cylinder head.
The thermostat stops the flow of the engine coolant from
the engine to the radiator in order to provide faster warm–
up, and to regulate the coolant temperature. The thermo-
stat remains closed while the engine coolant is cold, pre-
venting circulation of the engine coolant through the
radiator. At this point, the engine coolant is allowed to cir-
culate only throughout the heater core to warm it quickly
and evenly.
As the engine warms, the thermostat opens. This allows
the engine coolant to flow through the radiator, where the
heat is dissipated through the radiator. This opening and
closing of the thermostat permits enough engine coolant
to enter the radiator to keep the engine within proper en-
gine temperature operating limits.
The wax pellet in the thermostat is hermetically sealed in
a metal case. The wax element of the thermostat expands
when it is heated and contracts when it is cooled.
As the vehicle is driven and the engine warms, the engine
coolant temperature increases. When the engine coolant
reaches a specified temperature, the wax pellet element
in the thermostat expands and exerts pressure against the
metal case, forcing the valve open. This allows the engine
coolant to flow through the engine cooling system and cool
the engine.
As the wax pellet cools, the contraction allows a spring to
close the valve.
The thermostat begins to open at 87°C (189°F) and is fully
open at 102°C (216°F). The thermostat closes at 86°C
(187°F).

ENGINE COOLING 1D – 19
DAEWOO V–121 BL4
ELECTRIC COOLING FAN
CAUTION : Keep hands, tools, and clothing away
from the engine cooling fans to help prevent personal
injury. This fan is electric and can turn ON whether or
not the engine is running.
CAUTION : If a fan blade is bent or damaged in any
way, no attempt should be made to repair or reuse the
damaged part. A bent or damaged fan assembly
should always be replaced with a new one. Failure to
do so can result in personal injury.
The cooling fans are mounted behind the radiator in the
engine compartment. The electric cooling fans increase
the flow of air across the radiator fins and across the con-
denser on air condition (A/C)–equipped vehicles. This
helps to speed cooling when the vehicle is at idle or moving
at low speeds.
1.4L DOHC engine fan size is 340mm (13.4 in.) and
1.6L/1.8L DOHC engine main fan size is 300 mm (11.8
inches) in diameter with five blades to aid the air flow
through the radiator and the condenser. An electric motor
attached to the radiator support drives the fan.
A/C models have two fans – the main fan and the auxiliary
fan. The auxiliary fan is 300 mm (11.8 inches) in diameter.
Non–A/C models have only the main fan.
A/C OFF or Non–A/C Model (1.4L/1.6L)
S The cooling fans are actuated by the electronic
control module (ECM) using a low–speed cooling
fan relay and a high–speed cooling fan relay. On
A/C–equipped vehicles, a series/parallel cooling fan
relay is also used.
S The ECM will turn the cooling fans on at low speed
when the coolant temperature reaches 97.5°C
(207.5°F) and the cooling fans off at 95.25°C
(203.4°F).
A/C OFF or Non–A/C Model (1.8L)
S The cooling fans are actuated by the electronic
control module (ECM) using a low–speed cooling
fan relay and a high–speed cooling fan relay. On
A/C–equipped vehicles, a series/parallel cooling fan
relay is also used.
S The ECM will turn the cooling fans on at low speed
when the coolant temperature reaches 93°C
(199°F) and the cooling fans off at 90°C (194°F).
A/C ON (1.4L/1.6L)
S The ECM will turn the cooling fans on at low speed
when the A/C system is on. The ECM will change
to high speed when the coolant temperature reach-
es 101.25°C (214°F) or the high side A/C pressure
reaches 1859 kPa (270 psi).
S The cooling fans will return to low speed when the
coolant temperature reaches 99°C (210°F) and the
high side A/C pressure reaches 1449 kPa (210 psi).
A/C ON (1.8L)
S The ECM will turn the cooling fans on at low speed
when the A/C system is on. The ECM will change
to high speed when the coolant temperature reach-
es 97°C (207°F) or the high side A/C pressure
reaches 1859 kPa (270 psi).
S The cooling fans will return to low speed when the
coolant temperature reaches 94°C (201°F) and the
high side A/C pressure reaches 1449 kPa (210 psi).
ENGINE BLOCK HEATER
The vehicle is designed to accept an engine block heater
that helps to warm the engine and to improve starting in
cold weather. It also can help to reduce fuel consumption
while a cold engine warms up.
The engine block heater is located under the intake man-
ifold and uses an existing expansion plug for installation.

5–4WELECTRICAL WIRING DIAGRAMS
8. FATC (FULL AUTOMATIC TEMPERATURE CONTROL) 5–68. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) BLOWER MOTOR, INTAKE MOTOR, MODE MOTOR, MAX HIGH RELAY & POWER TR CIRCUIT 5–68. . . .
2) SENSOR(AMBIENT,INCAR,SUN&WATER), AIR MIX DOOR MOTOR, A/C COMPRESSOR & ECM
CIRCUIT5–70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1) MR–140/HV–2405–70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2) SIRIUS D45–72 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9. RADIATOR COOLING FAN CIRCUIT 5–74. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) COOLING FAN CIRCUIT(MR–140/HV–240) : DUAL 5–74. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) COOLING FAN CIRCUIT(MR–140/HV–240) : SINGLE 5–76. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3) COOLING FAN CIRCUIT(SIRIUS D4) : DUAL 5–78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4) COOLING FAN CIRCUIT(SIRIUS D4) : SINGLE 5–80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10. HEAD LAMP & HEAD LAMP LEVELING DEVICE(HLLD) CIRCUIT 5–82. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) NOTCH BACK5–82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) HATCH BACK5–84 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11. ILLUMINATION CIRCUIT5–86 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) ILLUMINATION CIRCUIT– W/O DIMMER CONTROL 5–86. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) ILLUMINATION CIRCUIT– W/ DIMMER CONTROL 5–88. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3) LAMP(LICENSE PLATE & W/ FRONT/REAR POSITION) CIRCUIT : NOTCH BACK 5–90. . . . . . . . . . . . . . . . . .
4) LAMP(LICENSE PLATE & W/ FRONT/REAR POSITION) CIRCUIT : HATCH BACK 5–92. . . . . . . . . . . . . . . . . .
12. FRONT & REAR FOG LAMP CIRCUIT 5–94. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) NOTCH BACK5–94 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) HATCH BACK5–96 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13. HAZARD & TURN SIGNAL LAMP CIRCUIT 5–98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) NOTCH BACK5–98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) HATCH BACK5–100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5–74WELECTRICAL WIRING DIAGRAMS
9. RADIATOR COOLING FAN CIRCUIT
1) COOLING FAN CIRCUIT (MR–140/HV–240) : DUAL
a. CONNECTOR INFORMATION
CONNECTOR(NO.)
(PIN NO. COLOR)
CONNECTING, WIRING HARNESSCONNECTOR POSITION
C101 (21 Pin, White)Body
Engine Fuse BlockEngine Fuse Block
C102 (11 Pin, White)Body
Engine Fuse BlockEngine Fuse Block
C104 (24 Pin, White)Front
Engine Fuse BlockEngine Fuse Block
C106 (20 Pin, White)Engine
Engine Fuse BlockEngine Fuse Block
C108 (24 Pin, Black)Body
EngineLeft Engine Fuse Block
C113 (16 Pin, Black)Body
FrontBehind ECM Bracket
C201 (76 Pin, Black)I.P
I.P Fuse BlockI.P Fuse Block
C202 (89 Pin, White)I.P
BodyLeft CO–Driver Leg Room
G101FrontBehind Left Head Lamp
G102FrontBehind Right Head Lamp
G107Engine (MR–140/HV–240)Under Start Motor
b. CONNECTOR IDENTIFICATION SYMBOL & PIN NUMBER POSITION

ZF 4 HP 16 AUTOMATIC TRANSAXLE 5A1 – 199
DAEWOO V–121 BL4
3. Install the shift lever and the shift lever nut.
Tighten
Tighten the shift lever nut to 10 NSm (89 lb–in).
4. Connect the shift control cable and the retaining
clip.
5. Connect the park/neutral position switch electrical
connector.
6. Connect the negative battery cable.
OIL COOLER PIPES/HOSES
Removal Procedure
Important : Place a drip pan under the hoses to catch the
fluid that will run out of the lines.
1. Disconnect the negative battery cable.
2. Raise and suitably support the vehicle.
3. Remove the engine under cover. Refer to Section
9N, Frame and Underbody.
4. Remove the oil cooler outlet pipe bolt from the right
lower side of the radiator.
5. Remove the oil cooler outlet pipe bracket bolt.
6. Remove the oil cooler outlet pipe bolt from the
transaxle side.
7. Remove the oil cooler outlet pipe assembly.

5A1 – 200IZF 4 HP 16 AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
8. Remove the oil cooler inlet pipe bolt from the left
lower side of the radiator.
9. Remove the oil cooler inlet pipe bolt from the trans-
axle side.
10. Remove the oil cooler inlet pipe assembly.
Installation Procedure
1. Install the oil cooler inlet pipe assembly and the
bolts.
Tighten
Tighten the oil cooler inlet pipe bolts to 35 NSm (26 lb–
ft).
2. Install the oil cooler outlet pipe assembly and the
bolts.
Tighten
Tighten the oil cooler outlet pipe bolts to 35 NSm (26
lb–ft).
3. Refill the transaxle fluid. Refer to ”Transaxle Fluid
Checking Procedure” in this section.
4. Install the engine under cover. Refer to Section 9N,
Frame and Underbody.
5. Connect the negative battery cable.

AISIN AUTOMATIC TRANSAXLE 5A2 – 109
DAEWOO V–121 BL4
Installation Procedure
1. Connect the negative battery cable.
2. Install the TCM and retaining bolts.
Tighten
Tighten the TCM retaining bolts to 5 NSm (44 Ib–in).
3. Connect the TCM electrical connector.
4. Connect the negative battery cable.
FLUID COOLER INLET PIPES AND
HOSES
Removal Procedure
1. Raise and support the vehicle.
2. Drain the transaxle fluid.
3. Remove the clip from the hose, then disconnect the
hose from the fluid cooler inlet pipe.
4. Remove the inlet pipe union bolt from the radiator.
5. Remove the fluid cooler inlet pipe bolt from the
transaxle.
6. Remove the inlet pipe fitting nut from the transaxle.
7. Remove the fluid cooler inlet pipe and hoses.

5A2 – 110IAISIN AUTOMATIC TRANSAXLE
DAEWOO V–121 BL4
Installation Procedure
1. Install the fluid cooler inlet pipe fitting nut into the
transaxle.
Tighten
Tighten the fluid cooler inlet pipe fitting nut to 35 NSm
(26 Ib–ft).
2. Install the fluid cooler inlet pipe bolt into the trans-
axle.
Tighten
Tighten the fluid cooler inlet pipe bolt to 9 NSm (80 Ib–
in).
3. Install the inlet pipe union bolt into the radiator.
Tighten
Tighten the inlet pipe union bolt to 35 NSm (26 Ib–ft).
4. Connect the hose to inlet pipe and install the clip
into the hose.
5. Lower the vehicle.
6. Fill the transaxle with the fluid.
FLUID COOLER OUTLET PIPE AND
HOSES
Removal Procedure
1. Drain the transaxle fluid.
2. Remove the front outlet pipe union bolt from the
radiator.
3. Remove the clip from the hose.
4. Remove the rear outlet pipe clip bolt from the trans-
axle.
5. Remove the rear outlet pipe fitting nut from the
transaxle.
6. Remove the fluid cooler outlet pipe and hoses.