Document ID# 339144
1999 Chevrolet/Geo Lumina
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Intake Manifold Replacement Upper
Removal Procedure
Important
This engine uses a sequential multiport fuel injection system. Connect the
injector wiring harness connectors to their appropriate fuel injector or
exhaust emissions and engine performance may be seriously affected. For the
correct injector wiring harness connector-to-fuel injector connection
procedure, refer to Engine Electrical.
Disconnect the battery ground (negative) cable. Refer to Refer to Battery
Negative Cable Disconnect/Connect Procedure in Engine Electrical.
Disconnect the vacuum hose connection from the throttle body air inlet duct.
Disconnect the wiring harness connection from the intake air temperature
(IAT) sensor in the throttle body air inlet duct. Refer to Intake Air
Temperature (IAT) Sensor Replacement in Engine Controls - 3.1L.
Remove the throttle body air inlet duct.
Drain the engine coolant from the cooling system. Refer to Draining and
Filling Cooling System in Engine Cooling.
Remove the accelerator control and cruise control cables with bracket from
the throttle body. Remove the wiring harness from the retainer. Refer to
Accelerator Controls Cable Bracket Replacement in Engine Controls - 3.1L.
Disconnect the following wiring harness connectors from the throttle body:
Throttle position (TP) sensor
Idle air control (IAC) valve
Disconnect the (left) front spark plug wires. Refer to Spark Plug Wire
Harness Replacement in Engine Electrical.
Disconnect the wiring harness attachment clips.
Camshaft position (CMP) sensor wiring harness
Left hand spark plug wire harness
Engine wiring harness
Remove the nut from the coolant pipe to the throttle body.
Disconnect the thermostat bypass pipe coolant hoses from the throttle body.
Refer to HVAC.
Remove the engine mount struts. Refer to Engine Mount Strut Replacement .
Rotate the engine forward for access.
Disconnect the right spark plug wire retaining clips.
Remove the spark plug wires at the coil pack.
Remove the ignition coil bracket with the coils, the purge solenoid, the
vacuum canister solenoid, the vacuum lines, and the electrical connections.
Refer to Ignition Control Module Replacement and Evaporative Emission (EVAP)
Canister Purge Valve Replacement in Engine Controls - 3.1L.
Disconnect the vacuum hose at the manifold air pressure (MAP) sensor and
upper intake manifold.
Remove the manifold air pressure (MAP) sensor and the bracket. Refer to
Manifold Absolute Pressure (MAP) Sensor Replacement in Engine Controls -
3.1L.
Disconnect the emission control vacuum harness.
Disconnect the vacuum hose connections from the upper intake manifold.
Vacuum booster hose
Automatic transaxle vacuum modulator hose
Heater and air conditioning vacuum source hose
Fuel pressure regulator
Remove the drive belt. Refer to Drive Belt Replacement .
Remove the front generator brace. Refer to Generator Brace Replacement in
Engine Electrical.
Remove the rear generator brace. Refer to Generator Brace Replacement in
Engine Electrical.
Remove the exhaust gas recirculation (EGR) valve. Refer to Exhaust Gas
Recirculation (EGR) Valve Replacement in Engine Controls - 3.1L.
Remove the right hand upper intake manifold bolts and studs.
Remove the left hand upper intake manifold bolts.
Remove the upper intake manifold.
Remove the upper intake manifold gasket.
If replacing the upper intake manifold, remove the throttle body. Refer to
Throttle Body Assembly Replacement in Engine Controls - 3.1L.
Clean the seal surfaces on the manifold with degreaser.
Installation Procedure
If removed, install the throttle body. Refer to Throttle Body Assembly
Replacement in Engine Controls - 3.1L.
Install the upper intake manifold gasket.
Install the upper intake manifold.
Loosely install the left hand upper intake manifold bolts.
Loosely install the right hand upper intake manifold bolts and studs.
Notice
Use the correct fastener in the correct location. Replacement fasteners must
be the correct part number for that application. Fasteners requiring
replacement or fasteners requiring the use of thread locking compound or
sealant are identified in the service procedure. Do not use paints,
lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces
unless specified. These coatings affect fastener torque and joint clamping
force and may damage the fastener. Use the correct tightening sequence and
specifications when installing fasteners in order to avoid damage to parts
and systems.
Install the upper intake manifold bolts and studs. Tighten
Tighten the upper intake manifold bolts and studs to 25 N·m (18 lb ft).
Install the exhaust gas recirculation (EGR) valve. Refer to Exhaust Gas
Recirculation (EGR) Valve Replacement in Engine Controls - 3.1L.
Install the rear generator brace. Refer to Generator Brace Replacement in
Engine Electrical.
Install the front generator brace. Refer to Generator Brace Replacement in
Engine Electrical.
Connect the vacuum hose connections to the upper intake manifold.
Vacuum booster hose
Automatic transaxle vacuum modulator hose
Heater and air conditioning vacuum source hose
Fuel pressure regulator
Connect the emission control vacuum harness.
Install the manifold air pressure (MAP) sensor and bracket. Refer to
Manifold Absolute Pressure (MAP) Sensor Replacement in Engine Controls -
3.1L.
Connect the vacuum hose at the manifold air pressure (MAP) sensor and the
upper intake manifold.
Install the ignition coil bracket with the coils, the purge solenoid, the
vacuum canister solenoid, the spark plug wire retainers, the plug wires at
the ignition module, the vacuum lines, and the electrical connections. Refer
to Ignition Control Module Replacement and Evaporative Emission (EVAP)
Canister Purge Valve Replacement in Engine Controls - 3.1L.
Return the engine to the proper position.
Install the engine mount struts. Refer to Engine Mount Strut Replacement and
Engine Mount Strut Replacement .
Connect the thermostat bypass pipe coolant hoses to the throttle body.
Install coolant pipe nut to throttle body.
Connect the wiring harness attachment clips.
Camshaft position (CMP) sensor wiring harness
Left hand spark plug wire harness
Engine wiring harness
Connect the left hand spark plug wires. Refer to Spark Plug Wire Harness
Replacement in Engine Electrical.
Connect the wiring harness connectors to the throttle body.
Throttle position (TP) sensor
Idle air control (IAC) valve
Install the accelerator control and cruise control cables with bracket to
the throttle body. Install the wiring harness to the retainer. Refer to
Throttle Body Assembly Replacement in Engine Controls - 3.1L.
Fill the cooling system with engine coolant. Refer to Draining and Filling
Cooling System in Engine Cooling.
Install the throttle body air inlet duct.
Connect the wiring harness connection to the intake air temperature (IAT)
sensor in the throttle body air inlet duct. Refer to Intake Air Temperature
(IAT) Sensor Replacement in Engine Controls - 3.1L.
Connect the vacuum hose connection to the throttle body air inlet duct.
Connect the battery ground (negative) cable. Refer to Refer to Battery
Negative Cable Disconnect/Connect Procedure in Engine Electrical.
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Intake Manifold Replacement Lower
Removal Procedure
Important
This engine uses a sequential multiport fuel injection system. Injector
wiring harness connectors must be connected to their appropriate fuel
injector or exhaust emissions and engine performance may be seriously
affected.
Disconnect the battery ground (negative) cable. Refer to Battery Negative
Cable Disconnect/Connect Procedure in Engine Electrical.
Remove the upper intake manifold. Refer to Intake Manifold Replacement .
Disconnect the radiator inlet hose from the engine. Refer to Radiator Hose
Replacement - Inlet in Engine Cooling.
Disconnect the thermostat bypass hose from the thermostat bypass pipe and
lower intake manifold pipe.
Remove the thermostat bypass pipe.
Remove the left (front) valve rocker arm cover. Refer to Valve Rocker Arm
Cover Replacement .
Remove the generator. Refer to Generator Replacement in Engine Electrical.
Remove the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm
Cover Replacement .
Disconnect the engine coolant temperature (ECT) wiring harness.
Disconnect and remove the fuel injector and manifold air pressure (MAP)
wiring harness.
Remove the fuel pipe clip bolt.
Remove the fuel pipe clip.
Disconnect the fuel feed pipe from the fuel injector rail. Refer to Fuel
Hose/Pipes Replacement - Filter to Engine in Engine Controls - 3.1L.
Disconnect the fuel return pipe from the fuel injector rail. Refer to Fuel
Hose/Pipes Replacement - Filter to Engine in Engine Controls - 3.1L.
Remove the fuel injector rail. Refer to Fuel Rail Assembly Replacement in
Engine Controls - 3.1L.
Remove the power steering pump from the front engine cover and reposition.
Refer to Power Steering Pump Replacement in Power Steering System.
Disconnect the heater inlet pipe with heater hose from the lower intake
manifold and reposition. Refer to Heater Pipe Replacement - Inlet in HVAC.
Remove the lower intake manifold bolts.
Remove the lower intake manifold.
Remove the valve rocker arms and the push rods. Refer to Valve Rocker Arm
and Push Rod Replacement .
Remove the lower intake manifold gaskets and seals.
Clean the lower intake manifold gasket and seal surfaces on the cylinder
heads and the engine block.
Clean the gasket and seal surfaces on the lower intake manifold with
degreaser.
Remove all the loose RTV sealer.
If replacing the lower intake manifold remove the engine coolant temperature
(ECT) sensor. Refer to Engine Coolant Temperature (ECT) Sensor Replacement
in Engine Controls - 3.1L.
If replacing the lower intake manifold remove the water outlet bolts.
Remove the water outlet.
If replacing the lower intake manifold remove the thermostat.
Installation Procedure
If removed, install the thermostat.
If removed, install the water outlet.
Notice
Refer to Fastener Notice in Cautions and Notices.
Install the water outlet bolts. Tighten
Tighten the water outlet bolts to 25 N·m (18 lb ft).
If removed, install the engine coolant temperature (ECT) sensor. Refer to
Engine Coolant Temperature (ECT) Sensor Replacement in Engine Controls -
3.1L.
Important
All gasket-mating surfaces need to be free of oil, and foreign material. Use
GM P/N 12346139 (Canadian P/N 10953463) or equivalent to clean surfaces.
Install the lower intake manifold gaskets.
With gaskets in place supply a small drop 8-10 mm (0.31 -0.39 in) of RTV
Sealer GM P/N 12346141 (Canadian P/N 10953433) or equivalent to the 4
corners of the intake manifold to block joint (1).
Connect the 2 small drops with a bead of RTV Sealer that is between 8-10 mm
(0.30-0.39 in) wide and 3.0-5.0 mm (0.12-0.20 in) thick (2).
Install the valve rocker arms and pushrods. Refer to Valve Rocker Arm and
Push Rod Replacement .
Notice
Refer to Fastener Notice in Cautions and Notices.
Important
All lower intake manifold bolts need to be cleaned, free of any foreign
material, and reused only if new bolts are unavailable. Use GM P/N 12345382
(Canadian P/N 10953489) or equivalent and apply to the old intake manifold
bolt threads.
Important
Manufacturer recommends the center bolts be fully torqued before the
diagonal bolts to assure proper seal ability.
Important
Lower intake manifold bolts in location 6 and 7 should be torqued to
specification using a crows foot type tool.
Install the lower intake manifold. Install the lower intake manifold bolts.
Tighten
Tighten the lower intake manifold bolts in sequence to 7 N·m (62 lb in) on
the first pass.
Tighten the lower intake manifold bolts (1,2,3,4) in sequence to 13 N·m (115
lb in) on the final pass.
Tighten the lower intake manifold bolts (5,6,7,

in sequence to 25 N·m (18
lb ft) on the final pass.
Install the heater inlet pipe.
Install the heater inlet pipe nut. Tighten
Tighten the heater inlet pipe nut to 25 N·m (18 lb ft).
Install the power steering pump to the front engine cover. Refer to Power
Steering Pump Replacement in Power Steering System.
Important
Do not press on the fuel pressure regulator valve when installing the fuel
injector rail assembly.
Install the fuel injector rail assembly.
Install the fuel injector O-rings using GM P/N 12345616 (Canadian P/N
993182).
Install the injector nozzles into the lower intake manifold injector bores.
Press on the injector rail using the palms of both hands until the injectors
are fully seated.
Install the fuel injector rail bolts. Tighten
Tighten the fuel injector rail bolts to 10 N·m (89 lb in).
Connect the fuel return pipe to the fuel injector rail. Refer to Fuel
Hose/Pipes Replacement - Filter to Engine in Engine Controls - 3.1L.
Connect the fuel feed pipe to the fuel injector rail. Refer to Fuel
Hose/Pipes Replacement - Filter to Engine in Engine Controls - 3.1L.
Install the fuel feed and return pipe retaining clip.
Install the fuel feed and return pipe retaining clip bolt. Tighten
Tighten the fuel feed and return pipe retaining clip bolt to 8 N·m (71 lb
in).
Connect the thermostat bypass hose to the thermostat bypass pipe and lower
intake manifold pipe.
Connect the radiator inlet hose to the engine. Refer to Radiator Hose
Replacement - Inlet in Engine Cooling.
Install and connect the fuel injector and manifold air pressure (MAP) wiring
harness.
Connect the engine coolant temperature (ECT) wiring harness.
Install the right (rear) valve rocker arm cover. Refer to Valve Rocker Arm
Cover Replacement .
Install the generator. Refer to Generator Replacement in Engine Electrical.
Install the left (front) valve rocker arm cover. Refer to Valve Rocker Arm
Cover Replacement .
Install the upper intake manifold. Refer to Intake Manifold Replacement .
Connect the battery ground (negative) cable. Refer to Battery Negative Cable
Disconnect/Connect Procedure in Engine Electrical.
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Document ID# 339149
1999 Chevrolet/Geo Lumina
<Dogg DeleteThis @Datt.s> wrote in message
news:pe5g3414eab3pnup2vn91posedd6ihduq3@4ax.com...
> Can anyone please post or direct me to the procedures for replacing
> the intake gasket. It's my turn to fix my GM leaking gasket problem.
> I've read as much here as I can about the updated gasket and sealant,
> I'm just wondering about what parts I'll need to remove to get to it.
>
> 99 Lumina 3.1