How much time to replace intake manifold gasket?

Have you replaced the intake manifold gaskets? These engines have a history of leaking intake manifold gaskets. Water leaks into the intake and is burned off in the cylinders. If the engine overheats enough times, you will eventually blow the head gaskets.

Start by performing a compression check to make sure you haven't blown the head gaskets. Then make sure the car is really overheating (i.e. check the temperature of the engine with a infrared thermometer (they are cheap at Harbor Freight).

If it is really overheating, and you've really changed everything else, you need to change the intake manifold gaskets. Be sure to get the improved gaskets from the parts store (they have a metal core with rubber coating).

Well basically, you remove the intake plenum and replace the gasket and reinstall the plenum. Here are the steps:

1. Disconnect the negative battery cable from the remote jumper terminal located at the right strut tower.
2. Remove the air inlet resonator and tube.
3. Remove the throttle actuator cables from the throttle arm and bracket.
4. Disconnect Secondary Runner Valve (SRV), Manifold Tuning Valve (MTV), Throttle Position Sensor (TPS), Idle Air Control (IAC) motor electrical connectors.
5. Remove the electrical connector and the Intake Air Temperature/Manifold Absolute Pressure (TMAP) sensor.
6. Disconnect vacuum hoses from the Secondary Runner Valve (SRV) reservoir, Speed Control reservoir, and PCV.
7. Remove right and left intake manifold supports.
8. Remove support brackets at the intake manifold front corners and MTV.
9. Loosen upper fastener attaching throttle body to support bracket.
10. Remove clips attaching EGR tubes to intake manifold.
11. Remove intake manifold bolts and manifold
12. Remove old gaskets, Clean gasket surfaces, and install new gaskets.
13. Reverse steps to reinstall manifold

I had this happen to me the first time I replaced my intake manifold gaskets. It was hard to install the intake and gasket moved just enough and I had a coolant leak. Removed manifold and installed new gaskets and problem was solved. Good Luck.

3.8L Engine (most common) Upper Intake Manifold To Remove:

1. Drain the cooling system.
2. Remove or disconnect the following:
   • Negative battery cable.
   • Fuel injector sight shield.
   • Air cleaner intake duct.
   • Right spark plug wires from the ignition control module and reposition.
3. Relieve the fuel pressure.
4. Remove or disconnect the following:
   • Fuel rail assembly.
   • Brake booster hose from the vacuum source manifold in the upper intake manifold.
   • Exhaust Gas Recirculation Valve (EGR) wiring harness heat shield nut, bolt and the EGR heat shield.
   • Throttle body support bracket upper bolt.
5. Disconnect the electrical connectors from the following:
   • EVAP purge solenoid
   • Throttle Position (T/P) sensor
   • Idle Air Control (IAC) valve
   • Manifold Absolute Pressure (MAP) sensor
   • Mass Air Flow (MAF) sensor
   • EVAP purge solenoid vacuum line from the throttle body.
   • Accelerator and the cruise control cables with the bracket from the throttle body.
6. Remove or disconnect the following:
   • Upper intake manifold bolts and stud.
   • Clean the upper intake manifold bolt threads.
7. Remove or disconnect the following:
   • Upper intake manifold by lifting the back of the intake and sliding the manifold forward from the throttle body support bracket.
   • Upper-to-lower intake manifold carrier gasket from the upper intake manifold.
8. If the upper intake manifold is being replaced, remove the following:
   • Throttle body assembly.
   • Manifold Absolute Pressure (MAP) sensor.
   • Positive Crankcase Ventilation (PCV) valve.
   • Vacuum source manifold.

Upper intake manifold bolt torque sequence (3.8L engine)

To Install:

1. If the manifold was replaced, install or connect the following:
   • Vacuum source manifold.
   • Positive Crankcase Ventilation (PCV) valve.
   • Manifold Absolute Pressure (MAP) sensor.
   • Throttle body assembly.
   • Upper-to-lower intake manifold carrier gasket to the upper intake manifold.
2. Carefully place the upper intake manifold onto the lower intake manifold. Ensure that the alignment pins in the upper intake manifold align with the holes in the lower intake manifold. NOTE: Apply thread lock compound, to the bolt threads before assembly.
   
3. Install or connect the following:
   • Upper intake manifold. Tighten the upper intake manifold bolts in sequence to 89 in lbs (10 Nm)
   • Accelerator and the cruise control cables with the bracket to the throttle body.
   • EVAP purge solenoid vacuum line to the throttle body.
4. Connect the electrical connectors to the following:
   • Mass Air Flow (MAF) sensor
   • Manifold Absolute Pressure (MAP) sensor
   • Idle Air Control (IAC) valve
   • Throttle Position (T/P) sensor
   • EVAP purge solenoid
5. Install or connect the following:
   • Throttle body upper support bracket bolt. Tighten the bolt to 89 in lbs (10 Nm)
   • EGR valve wiring harness heat shield, nut and the bolt. Tighten the nut and the bolt to 89 in lbs (10 Nm)
   • Brake booster hose to the vacuum source manifold.
   • Fuel rail assembly.
   • Right spark plug wires.
   • Air cleaner intake duct.
   • Fuel injector sight shield.
6. Connect the negative battery cable.
7. Fill the cooling system.
8. Inspect for fluid or vacuum leaks.

Lower Intake Manifold (W/O Supercharger) To Remove:

1. Remove or disconnect the following:
   • Upper intake manifold.
   • Generator brace.
   • Drive belt tensioner with the mounting bracket and the heater water bypass inlet pipe.
   • Exhaust gas recirculation EGR outlet pipe bolt from the lower intake manifold.
   • Radiator inlet hose from the water outlet housing.
   • ECT sensor electrical connector.
   • Right upper engine mount strut bracket.
   • Generator brace bracket bolts.
   • Generator brace bracket.
   • Lower intake manifold bolts.
   • Lower intake manifold.
   • Lower intake manifold seals.
   • Lower intake manifold gaskets.
2. If replacing the lower intake manifold, Remove or disconnect:
   • Water outlet housing bolt and stud
   • Water outlet housing
   • Gasket and the thermostat.
   • ECT sensor.
3. Inspect the flatness of inlet flanges.
4. Clean the intake manifold mating surfaces.
5. Clean the intake manifold bolts and bolt holes of adhesive compound.

To Install:

1. If removed, install the ECT sensor.
   • Tighten the ECT sensor to 18 ft. lbs. (25 Nm)
2. If removed, install the thermostat, the gasket, and the water outlet housing.
3. If removed, install the water outlet housing bolt and the stud.
   • Tighten the bolt and stud to 20 ft. lbs. (27 Nm)
4. Install or connect the following:
   • Lower intake manifold gaskets. NOTE: Apply sealer GM P/N 12346286 (Canadian P/N 10953472) or equivalent to the ends of the intake manifold seals.
     
   • Lower intake manifold seals.
   • Lower intake manifold.
   • Lower intake manifold bolts.
   NOTE: Apply thread lock compound GM P/N 12345382 (Canadian P/N 10953489) or equivalent to the two hidden bolts and ensure they are installed.
   
5. Tighten the lower intake manifold bolts in sequence to 11 ft. lbs. (15 Nm)
   
   
6. Install or connect the following:
   • Generator brace bracket.
   • Generator brace bracket bolts. Tighten the bolts to 37 ft. lbs. (50 Nm)
   • Right upper engine mount strut bracket.
   • ECT sensor electrical connector.
   • Radiator inlet hose to the water outlet housing.
   • EGR outlet pipe to the lower intake manifold.
   • EGR outlet pipe bolt to the lower intake manifold. Tighten the bolt to 21 ft. lbs. (29 Nm)
   • Drive belt tensioner.
   • Generator brace.
   • Upper intake manifold.
7. Inspect for leaks.

Lower Intake Manifold (W/ Supercharger) To Remove:

1. Disconnect the negative battery cable.
2. Drain the cooling system.
3. Remove the supercharger.
4. Remove the thermostat housing.
5. Remove the EGR pipe at the intake manifold.
6. Disconnect the electrical connection at the temperature sensor.
7. Remove the intake manifold and gaskets.

NOTE: The coolant bypass tube will release from the intake manifold when the manifold is removed.
To Install:

1. Clean the gasket sealing surfaces.
2. Install the intake manifold gaskets.
3. Align the coolant bypass tube with the opening in the intake manifold and install the manifold. Tighten the bolts to 11 lb ft (15 Nm).
4. Install the electrical connector to the temperature sensor.
5. Install the EGR pipe to the intake manifold.
6. Install the thermostat housing.
7. Install the supercharger.
8. Fill the cooling system.
9. Connect the negative battery cable.

you can check the intake gasket buy spraying some starting fluid near the intake while the car is running if the engine speeds up the gasket is gone. you intake could be no good

when u replace the head gaskets u must also replace any parts gasket that u remove (valve covers, intake manifold etc.) to get the heads off, they sell what is called a "Valve Grind" gasket set that is what u need, it will have all the gaskets in it u need..

oil from the pcv valve going into your intake manifold will cause a gasket to swell. but it should not be to the point where it's noticeable. you should probably replace the intake manifold gasket at this point.

answer , very carefully ...

drain coolant , remove and mark all vacuum lines , make a schematic to diagram your hose routing, disconnect and plug all fuel lines, remove distributor and mark location of rotor, disconnect battery, remove any necessary cables, brackets and or accesseries, remove intake mounting bolts, note length of bolts and reference location, pry up on intake , remove intake, scrape old gasket off , must be very clean to reinstall new gasket or you will cause a leak..

2 upper pellum and lower intake gasket( both are called intake gaskets) I did it. time consuming alittle but if your ave or above with mechanics then you'll save yourself $2000.. the new pelunum and gasket cost $130 and it comes with improved gasket and a replacement pipe the melts also. lower gasket $40? need more help or info email me! Richie