Intake air temperature DAEWOO LACETTI 2004 Service Repair Manual

1.4L/1.6L DOHC ENGINE MECHANICAL 1C1 – 5
DAEWOO V–121 BL4
FASTENER TIGHTENING SPECIFCATIONS
ApplicationNSmLb–FtLb–In
Air Cleaner Housing Bolts10–89
Camshaft Cap Bolts1612–
Camshaft Cover Nuts10–89
Connecting Rod Bearing Cap Bolts25
+ 30° + 15°18
+ 30° + 15°–
Coolant Temperature Sensor2015–
Crankshaft Bearing Cap Bolts50
+ 45° + 15°37
+ 45°+ 15°–
Crankshaft Cover Nuts5~8–44~71
Crankshaft Pulley Bolt95 NSm
+ 30° + 15°––
Cylinder Head Bolts (Cylinder Head Mounting Bolts)25 + 70°
+ 70° + 50°18 + 70°
+ 70° + 50°–
Direct Ignition System Coil Mounting Bolts10–89
Direct Ignition System Coil Mounting Bracket Bolts10–89
Engine Mount Attaching Bolts3022–
Engine Mount Bracket Attaching Bolts/Nuts5037–
Exhaust Camshaft Gear Bolt67.549–
Exhaust Flex Pipe–to–Catalytic Converter or Connecting Pipe
Retaining Nut3526–
Exhaust Flex Pipe–to–Exhaust Manifold Retaining Nuts3526–
Exhaust Gas Recirculation Valve Adapter Bolts2518–
Exhaust Manifold Heat Shield Bolts1511–
Exhaust Manifold Retaining Nuts2518–
Flexible Plate Bolts6044–
Flexible Plate Inspection Cover Bolts10–89
Flywheel Bolts35
+ 30° + 15°25
+ 30° + 15°–
Flywheel Inspection Cover Bolts12–106
Front Timing Belt Cover Bolts (Upper and Lower)10–89
Fuel Rail Assembly Retaining Bolts2518–
Fuel Rail Retaining Bolts2518–
Generator Upper Retaining Bolt2015–
Intake Camshaft Gear Bolt67.549–
Intake Manifold Retaining Bolts/Nuts2518–
Intake Manifold Support Bracket Lower Bolt2518–
Intake Manifold Support Bracket Upper Bolts2518–
Lower Front Timing Belt Cover Bolts10–89
Oil Pan Flange Bolts7555–
Oil Pan Retaining Bolts10–89
Oil Pan Drain Plug3526–
OIl Pressure Switch4030–

1.4L/1.6L DOHC ENGINE MECHANICAL 1C1 – 17
DAEWOO V–121 BL4
6. Disconnect the intake manifold pressure sensor
connector, attaching bolt and vaccum hose.
7. Disconnect the intake manifold air temperature sen-
sor(MAT) connector and remove the MAT sensor.
8. Remove the intake manifold upper bracket.
9. Remove the fule rail bolt and the fuel rail.
10. Remove the all the vaccum hoses from the intake
manifold including PCV hose and brake booster
vaccum hose.
11. Remove the exhaust gas recirculation(EGR) pipe.

1.4L/1.6L DOHC ENGINE MECHANICAL 1C1 – 19
DAEWOO V–121 BL4
4. Install the intake manifold support bracket.
Tighten
Tighten the intake manifold support bracket upper
bolts to 25 NSm (18 lb–ft) and lower bolts to 45 NSm
(33 lb–ft).
5. Install the alternater.
6. Install the fuel rail.
7. Install the fuel rail bolts.
8. Install the intake manifold upper bracket.
9. Install the intake manifold upper bracket bolts.
10. Install the intake manifold air temperature sen-
sor(MAT) and connect the MAT sensor connecter.
11. Install the intake manifold pressure sensor and vac-
cum hose.

1C1 – 22I1.4L/1.6L DOHC ENGINE MECHANICAL
DAEWOO V–121 BL4
6. Drain the engine oil and remove the camshaft cov-
er. Refer to this section.
7. Remove the air cleaner housing.
8. Remove the throttle cable and inlet/outlet coolant
hoses.
9. Remove the thermostat upper hose.
10. Remove the intake manifold pressure sensor, in-
take air temperature sensor and coolant tempera-
ture sensor.
11. Remove the intake manifold support bracket.

1C1 – 28I1.4L/1.6L DOHC ENGINE MECHANICAL
DAEWOO V–121 BL4
25. Install the timing belt.
26. Rotate the water pump clockwise using the timing
belt adjuster J–42492 to apply tension to the timing
belt.
Tighten
Tighten the water pump retaining bolts to 10 NSm (89
lb–in).
27. Check and adjust the timing belt tension. Refer to
”Timing Belt Check and Adjust” in this section.
28. Install the upper and lower front timing belt covers.
Tighten
Tighten the upper and lower front timing belt covers
bolts to 10 NSm (89 lb–in).
29. Install the crank shaft pulley bolt.
Tighten
Tighten the crank shaft pulley bolt to 95 NSm (70 lb–ft)
and retighten 30 degrees plus 15 degrees.
30. Install the serpentine accessory drive belt. Refer to
Section 6B, Power Steering Pump.
31. Connect the upper radiator hose to the thermostat
housing.
32. Install the front wheel and splash shield. Refer to
Section 2E, Tires and Wheels.
33. Install the air cleaner housing.
Tighten
Tighten the air cleaner housing bolts to 10 NSm (89 lb–
in).
34. Connect the breather tube to the cam shaft cover.
35. Install the crank shaft pulley bolt.
36. Connect the MAT sensor connector.
37. Connect the intake manifold pressure sensor, in-
take air temperature sensor and coolant tempera-
ture sensor connector.

1C1 – 58I1.4L/1.6L DOHC ENGINE MECHANICAL
DAEWOO V–121 BL4
UNIT REPAIR
CYLINDER HEAD AND VALVE TRAIN
COMPONENTS
Tools Required
MKM–571–B Gauge
KM–340–0 Cutter Set
KM–340–7 Guide Drift
KM–340–13 Cutters
KM–340–26 Cutters
KM–348 Valve Spring Compressor
KM–653 Adapter
KM–805 Valve Guide Reamer
Disassembly Procedure
1. Remove the cylinder head with the intake manifold
and the exhaust manifold attached. Refer to ”Cylin-
der Head and Gasket” in this section.
2. Remove the engine coolant temperature sensor.
3. Remove the exhaust manifold heat shield bolts.
4. Remove the exhaust manifold heat shield.
5. Remove the exhaust manifold retaining nuts in the
sequence shown.
6. Remove the exhaust manifold.
7. Remove the exhaust manifold gasket.
8. Remove the exhaust manifold studs.
9. Remove the thermostat housing mounting bolts.
10. Remove the thermostat housing assembly.
11. Remove the fuel rail retaining bolts and the fuel rail
assembly.
12. Remove the intake manifold retaining nuts and re-
taining bolts in the sequence shown.
13. Remove the intake manifold.
14. Remove the intake manifold studs.

1C2 – 38I1.8L DOHC ENGINE MECHANICAL
DAEWOO V–121 BL4
3. Install the timing belt idler pulleys.
4. Install the timing belt idler pulley bolt and nut.
Tighten
Tighten the timing belt idler pulley bolt and nut to 25
NSm (18 lb–ft).
5. Tension the timing belt by turning the timing belt
automatic tensioner hex–key tab counterclockwise
until the pointer is aligned to the indicator.
Tighten
Tighten the timing belt automatic tensioner bolt to 25
NSm (18 lb–ft).
6. Install the front timing belt cover.
7. Install the front timing belt cover bolts.
Tighten
Tighten the front timing belt cover bolts to 6 NSm (53
lb–in).
8. Install the engine mount bracket and retaining bolts.
Tighten
Tighten the engine mount bracket retaining bolts to 55
NSm (41 lb–ft).
9. Remove the engine assembly support fixture
J–28467–B, and the channel X–28467–560.
10. Install the serpentine accessory drive belt. Refer to
Section 6B, Power Steering Pump.
11. Connect the negative battery cable.
INTAKE MANIFOLD
Removal Procedure
1. Remove the fuel pump fuse.
2. Start the engine. After it stalls, crank the engine for
10 seconds to rid the fuel system of fuel pressure.
3. Disconnect the negative battery cable.
4. Disconnect the charcoal canister purge (CCP) and
exhaust gas recirculation (EGR) solenoid from the
intake manifold and loosen the bracket bolt.
5. Drain the engine coolant. Refer to Section 1D, En-
gine Cooling.
6. Disconnect the manifold air temperature sensor
(MAT) connector.
7. Disconnect the air cleaner outlet hose from the
throttle body.

1.8L DOHC ENGINE MECHANICAL 1C2 – 47
DAEWOO V–121 BL4
19. Disconnect the oxygen (O2) sensor connector, if
equipped.
20. Disconnect the idle air control (IAC) valve connec-
tor.
21. Disconnect the throttle position sensor (TPS) con-
nector.
22. Disconnect the engine coolant temperature sensor
(CTS) connector.
23. Disconnect the CTS connector.
24. Disconnect the generator voltage regulator connec-
tor and power lead.
25. Disconnect all of the necessary vacuum lines, in-
cluding the brake booster vacuum hose.
26. Disconnect the fuel return line at the fuel rail.
27. Disconnect the fuel feed line at the fuel rail.
28. Remove the fuel rail and injector channel cover as
an assembly. Refer to Section 1F, Engine Controls.
29. Disconnect the throttle cable from the throttle body
and the intake manifold bracket.
30. Disconnect the coolant hose at the throttle body.
31. Disconnect the heater outlet hose at the coolant
pipe.
32. Disconnect the coolant bypass hose from the cylin-
der head.
33. Disconnect the surge tank coolant hose from the
coolant pipe.
34. Disconnect the lower radiator hose from the coolant
pipe.
35. Disconnect the starter solenoid ”S” terminal wire
and power lead.
36. Remove the A/C compressor. Refer to Section 7B,
Manual Control Heating, Ventilation, and Air Condi-
tioning Systems.
37. Remove the exhaust flex pipe retaining nuts from
the exhaust manifold studs.
38. Remove the exhaust flex pipe retaining nuts from
the catalytic converter or the connecting pipe.
39. Remove the exhaust flex pipe.

1D – 4IENGINE COOLING
DAEWOO V–121 BL4
COOLING SYSTEM DIAGNOSIS
Engine Overheats
ChecksAction
Check for a loss of the coolant.Add the coolant.
Check for a weak coolant solution.Confirm that the coolant solution is a 50/50 mixture of eth-
ylene glycol and water.
Check the front of the radiator for any dirt, any leaves, or
any insects.Clean the front of the radiator.
Check for leakage from the hoses, the coolant pump, the
heater, the thermostat housing, the radiator, the core
plugs, or the head gasket.Replace any damaged components.
Check for a faulty thermostat.Replace a damaged thermostat.
Check for retarded ignition timing.Perform an ECM code diagnosis. Confirm the integrity of
the timing belt.
Check for an improperly operating electric cooling fan.Replace the electric cooling fan.
Check for radiator hoses that are plugged or rotted.Replace any damaged radiator hoses.
Check for a faulty water pump.Replace a faulty water pump.
Check for a faulty surge tank cap.Replace a faulty surge tank cap.
Check for a cylinder head or an engine block that is
cracked or plugged.Repair the damaged cylinder head or the damaged engine
block.
Loss of Coolant
ChecksAction
Check for a leak in the radiator.Replace a damaged radiator.
Check for a leak in the following locations:
S Surge tank.
S Hose.Replace the following parts, as needed:
S Surge tank.
S Hose.
Check for loose or damaged radiator hoses, heater hoses,
and connections.Reseat the hoses.
Replace the hoses or the clamps.
Check for leaks in the coolant pump seal.Replace the coolant pump seal.
Check for leaks in the coolant pump gasket.Replace the coolant pump gasket.
Check for an improper cylinder head torque.Tighten the cylinder head bolts to specifications.
Replace the cylinder head gasket, if needed.
Check for leaks in the following locations:
S Intake manifold.
S Cylinder head gasket.
S Cylinder block plug.
S Heater core.
S Radiator drain plug.Repair or replace any components, as needed, to correct
the leak.
Engine Fails to Reach Normal Operating Temperature or Cool Air
from the Heater
ChecksAction
Check to determine if the thermostat is stuck open or is the
wrong type of thermostat.Install a new thermostat of the correct type and heat range.
Check the coolant level to determine if it is below the MIN
mark on the surge tank.Add sufficient coolant to raise the fluid to the specified
mark on the surge tank.

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).