GM 24507501
Intake Manifold

To replace the lower Intake Manifold, first make sure the Fuel Injector wiring harness connectors are properly attached to their own fuel injectors to prevent excess emission of the engine and poor performance. Start off by removing the upper Intake Manifold, engine left and right-side valve rocker arm covers. Pull the Fuel Injector wiring harness connectors from the injector harness, noting the wiring harness connectors when masking tape with the cylinder number attached to each. Then, disconnect and remove the Fuel Injector, manifold air pressure (MAP), and ect wiring harness, then detected the fuel feed and return pipe from the Fuel Injector rail and lastly the Fuel Injector rail self. Do not remove the power steering pipes or hoses from the pump. Instead, pull off the Power Steering Pump from the covering at the front engine and leave it out of the way. Remove the heater inlet pipe with heater hose and inlet Radiator Hose from the engine and also thermostat bypass hose from the lower Intake Manifold pipe. Now remove the lower Intake Manifold bolts, and the lower Intake Manifold, loosen the valve rocker arms, and remove the push rods. Remove the lower Intake Manifold gaskets and seals, and clean the surfaces of the gaskets and seals on the cylinder heads, as well as the engine block. Perform a check on the lower Intake Manifold, and in case of replacement remove ect and therapist. For installation, apply a bead of 8 - 12 mm (0.08 - 0.11 inch) rtv sealer gm p/n 12345739 or equivalent to each ridge between the front and rear of the lower Intake Manifold and the engine block and install the lower Intake Manifold gaskets. Reinstall the push rods and fasten the valves rocker arms before reinstalling the lower Intake Manifold. Replace the new lower Intake Manifold bolts, tighten the vertical bolts (the 4 in the middle) at 7 nm (62 lb in,) the diagonal bolts (two on each end) should be tightened to 7 nm (62 lb in,) then tighten vertical bolts to 13 nm (115 lb in,) and blow diagonal bolts to 25 nm (18 lb ft). Connect the thermostat bypass hose to the lower Intake Manifold pipe, connect inlet Radiator Hose from engine to lower Intake Manifold pipe and connect heater inlet pipe and heater hose to lower Intake Manifold pipe. Mount the Power Steering Pump onto the front engine cover, the Fuel Injector rail, and the fuel feed and return pipe onto the Fuel Injector rail. Make sure that the terminals of the Fuel Injector wiring harness to their respective fuel injectors are connected, then install and connect the Fuel Injector, map, and ect wiring harness, and then the wiring harness to the ect sensor. Lastly, replace the engine right and left side valve rocker arm covers and upper Intake Manifold.

Replacement of the upper Intake Manifold requires the battery ground cable and Throttle Body iat sensor wiring harness attachment to be detached first. Start by disconnecting the Throttle Body air inlet duct and proceed to drain engine coolant from your vehicle's cooling system. Disassemble the accelerator control cable with the cruise control bracket from the Throttle Body and proceed by removing the Throttle Body itself. First disconnect the wiring harness attachment clips that serve the Camshaft Position Sensor and left spark plug wire harness and then remove the thermostat bypass pipe coolant hoses that connect to the Throttle Body. Disassemble the rear generator brace while you eliminate these subsequent components: the maintenance process includes removing vacuum lines from three separate components: upper Intake Manifold, map sensor, egr valve, followed by disconnecting Spark Plug Wires and igniting control modules and removing the upper Intake Manifold before replacing its gaskets and vacuum lines. Prior to adding Throttle Body and upper Intake Manifold gaskets you should clean all manifold seal surfaces with degreaser. Use threadlock gm p/n 12345382 or equivalent on the Intake Manifold bolts followed by upper Intake Manifold installation and torque upper Intake Manifold bolts to 25 nm (18 lb ft). The installation sequence includes upper Intake Manifold gaskets followed by the upper Intake Manifold and Ignition Control Module and then Spark Plug Wires and EGR Valve and MAP Sensor and vacuum lines for the upper Intake Manifold. Installation should begin with the rear generator brace followed by connecting thermostat bypass pipe coolant hoses to the Throttle Body. Wire harness connectors need to connect to throttle position (TP) sensor and idle air control (IAC) valve locations on the Throttle Body. After filling the cooling system with engine coolant, install the Throttle Body air inlet duct and carefully connect wiring harness connectors to the intake air temperature sensor within the duct and the vacuum hose to it. Finally, reinstall the negative Battery Cable.

To remove the lower Intake Manifold, you will need the following tools: torque angle meter (J 36660-A). Start with the upper Intake Manifold removal, followed by removal of engine left and right side valve rocker arm covers. Separate the lead from the engine coolant temperature (ECT) sensor, making sure to tag the power of every injector metal lead connector with masking duct tape for easy identification. Next, quite the Fuel Injector, manifold air pressure (MAP), and the ect wiring harness, remove the fuel feed and the return pipe from the Fuel Injector rail, as well as the Fuel Injector rail itself. It is recommended that one should not detach the power steering pipes or hoses from the Power Steering Pump, instead remove the Power Steering Pump from the front engine cover and place it on the side. Remove the heater inlet pipe with heater hose and the inlet Radiator Hose from the engine; the thermostat bypass hose may be removed from the lower Intake Manifold pipe as well. And then removing the push rods and rockers, the lower Intake Manifold bolts lower Intake Manifold loosen the valve rocker arms. Remove the lower Intake Manifold gaskets and seals, and scrape the surfaces of the cylinder heads and engine block, checking the lower Intake Manifold for damage. In case of lowering the Intake Manifold, the ect sensor as well as the thermostat will have to be removed. For installation, 8 - 12 mm (0.08 - 0.11 inch) bead of rtv sealer gm p/n 12345739 or equivalent on each ridge where the front and rear of the lower Intake Manifold touches to the engine block, then lower Intake Manifold gaskets are then installed. Install the push rods and tighten the valve rocker arms, tightening vale rocker arm bolts supplying the vertex angle meter testing the bright valve-pull arms to a torque of 19 nm (14 ft. Lbs.) + 30 degrees of angle. Install the lower Intake Manifold bolt and its mount, make sure that you tighten the vertical bolts first and then diagonal in order to prevent oil leakage. Apply sealer gm p/n 12345382 or equivalent on the lower intake bolts threads and install new lower intake bolts per the specified torque sequence. Connect the thermostat bypass hose, the inlet Radiator Hose, and heater inlet pipe and heater hose to the lower Intake Manifold, reinstall the Power Steering Pump to the front engine cover. Install the Fuel Injector rail and join the fuel feed and return pipe, to make sure the Fuel Injector wiring harness connectors are correctly connected to their related fuel injectors so as to prevent excessive exhaust and poor engine performance. Lastly, attach and connect the Fuel Injector, map, and ect wiring harness, ect wiring connect to the ect sensor followed with full reinstallation of the engine right and left side of valve rocker arm covers before completing with the upper Intake Manifold installation.

Connect the vacuum brake booster hose to the upper intake manifold.

Disconnect and remove the fuel injector, manifold air pressure (MAP), and ECT wiring harness, followed by the fuel feed and return pipe from the fuel injector rail, including the retaining clip bolt and clip.

Connect the wiring harness connectors to the throttle body, install the accelerator control and cruise control cables with bracket to the throttle body, and replace the throttle body air inlet duct before filling the cooling system with engine coolant.

Remove the accelerator control and cruise control cables with bracket, and disconnect the wiring harness connectors for the throttle position (TP) sensor and idle air control (IAC) valve.

Remove the right upper engine mount strut bracket, generator brace bracket bolts, and the generator brace bracket.

Remove the accelerator control and cruise control cables with the bracket from the throttle body, followed by the left side spark plug wires.

Attach the thermostat bypass pipe coolant hoses (3,4) to the throttle body.

Install new lower intake manifold bolts, tightening them in a specific sequence to the specified torque values.

Tighten the vertical bolts to 7 Nm and then to 13 Nm, and the diagonal bolts to 7 Nm and then to 25 Nm.

Install the ECT sensor, ensuring all gasket-mating surfaces are free of oil and foreign material, using GM P/N 12346139 (Canadian P/N 10953463) for cleaning.

Remove the upper intake manifold, left and right valve rocker arm covers, and disconnect the engine coolant temperature (ECT) sensor electrical connector.

Remove the water outlet housing bolts, the water outlet housing, gasket, and thermostat, as well as the ECT sensor.

Reconnect the thermostat bypass pipe coolant hoses to the throttle body.

Tighten the vertical lower intake manifold bolts to 7 Nm (62 lb in), then the diagonal lower intake manifold bolts to 7 Nm (62 lb in), followed by tightening the vertical bolts to 13 Nm (115 lb in) and the diagonal bolts to 25 Nm (18 lb ft).

Remove the power steering pump from the front engine cover and set it aside.

Remove the throttle body and the upper intake manifold gasket, then clean and inspect the upper intake manifold.

Tighten the vertical bolts before the diagonal bolts to prevent oil leaks.

Torque Angle Meter (J 36660-A).

Label each fuel injector wiring harness connector with masking tape for identification.