GM 12581115
Intake Manifold

For replacement of Intake Manifold, first loosen the clamp on the air cleaner sides and at the Throttle Body body and remove the air cleaner outlet duct. Loosen the Intake Manifold sight shield bolt, then remove the sight shield from the bracket, then the sight shield bracket and nuts. Relieve the fuel system pressure and disconnect the lines of the fuel feed and return lines. Vehicle harness clips disconnect from studs front of dash and wheelhouse splash panel. Remove the pressure cycling switch , surge tank switch , mass air flow (MAP) sensor. Reposition the engine harness branch on the topsurface of the engine and remove the connector position assurance (CPA) retainer at the ignition coil harness and disconnect the manifold absolute pressure(MAP) sensor, ignition coil harness and the engine coolant temperature (ECT) sensor. The parts to be removed include the engine harness bolts and studs, cpa retainer at the pioneer haul out coil harness, generator , injector harness , ignitors coil harness , throttle position (TP) sensor , electronic throttle control (Etc), and purge valve solenoid to be disconnected. Slide the engine harness to the driver side of the engine compartment, unplug the bypass valve vacuum hose from the Intake Manifold, and disconnect the exhaust gas recirculation (EGR) valve electrical connector. Loosen the bolts on the egr pipe on the egr adapter and reposition the egr pipe and discard the EGR Valve pipe gasket. Take out the fuel pressure regulator vacuum hose, and when replacing the Intake Manifold, remove the Fuel Rail studs and the Fuel Rail. Remove the Intake Manifold bolts but without prying under the gasket surface and remove the Intake Manifold, discard Intake Manifold; side gaskets; end seals. Before replacing the Intake Manifold, remove the splash shield, otherwise, bring the new Intake Manifold in place. Make sure that the splash shield does snap fit between the cylinder heads, replace the Intake Manifold with new end seals and side gaskets to the cylinder heads, but made sure to align the gasket tabs properly. Install the Intake Manifold gaskets with this side up stamped in an upward direction and then install the Intake Manifold. Apply threadlock gm U.S. P/N 12345382, canada P/N10953489 or equivalent to a minimum of eight threads of the Intake Manifold bolts, and install. Make sure to tighten the Intake Manifold bolts in a sequence, using four passes: first pass: 5 nm (44 inch lbs), second pass: 5 nm (44 inch lbs) third pass:10 nm (89 inch lbs), and last pass: 12 nm (106 inch lbs). Apply clean engine oil to the o-ring seals on the fuel injectors and then attach them to the spray tip of each fuel injector. If replacing the Intake Manifold, the Fuel Rail must be installed and the Fuel Rail studs should be tightened to 12 nm (106 inch lb). Mount the fuel pressure regulator vacuum hose, egr valve pipe gasket, and align the egr pipe; squeeze and tighten the egr pipe bolts to 30 nm (22 ft. Lbs.). Connect the EGR Valve electrical connector, and the bypass valve vacuum hose to the Intake Manifold. Shove the engine harness in the engine compartment and join the generator , injector harness , ignition coil harness , tp sensor , and etc as well as purge valve solenoid . Mount the cpa retainer at the ignition coil harness and install the engine harness bolt and studs. The bolt is to be tightened to 5 nm (44 inch lbs.), while the studs are to be tightened to 10 nm (89 inch lbs.) connect the MAP Sensor , ignition coil harness & ect sensor and over the engine set the engine harness branch on the top of the engine. Concert the pressure cycling switch , surge tank switch and maf sensor before connecting the engine harness clip to the wheelhouse splash shield and the clips to the studs on the front of the dash. Connect the fuel feed and return pipes attaching the engine sight shield bracket and nuts tighten the nuts 5 nm (44 inch lbs.) and install the sight shield to the bracket and tighten the Intake Manifold sight shield bolt to 10 nm (89-inch lbs.). Finally, take a look at the air cleaner outlet duct and tighten the clamps where the Throttle Body and air cleaner are located at a torque of 4 nm (35 inch lbs.).

In order to change the Intake Manifold, the first task to undertake involve loosening the Throttle Body and air cleaner clamps, followed by the removal of the air cleaner outlet duct. Unfasten and take off the Intake Manifold sight shield from the stud and bracket, also where necessary take off the sight shield bracket nuts and the bracket. Drain fuel system pressure, then remove the feed and return pipes, and remove the clips from the engine harness from the studs on the front of the dash and the wheel house splash shield. Remove the pressure cycling switch , surge tank switch , and the mass airflow (MAF) sensor . Reposition the engine harness branch to the top of the engine and unplug the connector position assurance (CPA) retainer from ignition coil harness; disconnect the manifold absolute pressure (MAP) sensor, ignition coil harness, and engine coach temperature (ECT) sensor. Unbolt the engine harness bolts and studs, as well as disconnect the generator , injector harness , ignition coil harness , electronic throttle control (ETC) , and purge valve solenoid . The engine harness should be moved to the driver's side, the bypass valve vacuum hose should be removed from the Intake Manifold, the evaporative emission (EVAP) tube should be unhooked from the purge solenoid uncoupled anddisconnect it from the vent pipe at the rear of the engine and then remove from the evap tube. If you need to replace the Intake Manifold, loosen the Fuel Rail studs and the Fuel Rail, making sure you do not get pry under the gasket face. Unbolt and remove the intake bolts as well as the Intake Manifold itself, and throw the Intake Manifold side gaskets and end seals as those are non reusable. Take out the splash shield, also reusable, and if you replace the Intake Manifold, clean and check it. For installation, if you are replacing Intake Manifold, mount it, install the splash shield, which should snap into place between the cylinders heads, install the new Intake Manifold end seals, and side gaskets with the appropriate gasket tabs. Mount the Intake Manifold and apply thread lock (GM P/N 12345382 or Canadian P/N 10953489) to the Intake Manifold bolts and tighten in the defined sequence in four passes to the stipulated torque values. Oil the engine oil the Fuel Injector O-Ring seals and mount them onto the spray tip of each injector. If you need to replace the Intake Manifold, install the Fuel Rail and tighten the Fuel Rail studs to 12 nm (106 inch lbs.). Reconnect the evap tube to the vent pipe and clip it to the Fuel Rail while connecting it to the purge solenoid. Mount the bypass valve vacuum hose back at the inlet to the intake, put the engine harness over the engine compartment, and connect the generator, injector harness, ignition coil harness, etc as well as purge valve solenoid. Mounting of the cpa retainer onto the ignition coil harness, securing of the engine harness with a 16 nm/12 ft. Lbs. Bolt on the harness and 10 nm/89 inch lbs. Bolts on the studs and MAP Sensor, ignition coil harness, and ect sensor before installing the cpa retainer once again. Place the engine harness branch over the engine top, attach the pressure cycling switch , surge tank switch , and maf sensor, attach the engine harness clip to the wheel house splash shield and clip the studs to the front of dash. Lastly, link the fuel feed and return pipes, install the sight shield bracket and nuts tightening them to 5 nm (44 inch lbs.), put on the sight shield to the bracket, and affix the sight shield on the stud, put on the air cleaner outlet duct and tighten up the clamp at the Throttle Body and the air cleaner to 4 nm (35 inch lbs.).

Before replacing the Intake Manifold you should begin by disconnecting Throttle Body and fuel injectors. First disconnect the electrical connections of both the manifold absolute pressure (MAP) sensor and Knock Sensor before removing the Knock Sensor harness connector from the Intake Manifold. Set the electrical harness aside and if your car has vacuum braking set the vacuum brake booster hose loose at the Intake Manifold's rear side. First disconnect the positive crankcase ventilation (PCV) hose followed by removing the MAP Sensor. To remove the evaporative emission (EVAP) purge solenoid you must separate the solenoid from its vent tube and vapor pipe connections before removing the solenoid bolt and solenoid unit and isolator from the Intake Manifold. Begin by loosening all Intake Manifold bolts then eliminate the Intake Manifold from the engine along with the gaskets. Eliminate and discard the aged gaskets. Inspection and cleaning are optional steps for the Intake Manifold. First install new Intake Manifold gaskets onto the Intake Manifold before securing the manifold in position. Apply threadlock gm p/n 12345382 (Canadian P/N 10953489) with a 5 mm (0.20 inch) band to Intake Manifold bolts then tighten them by sequence in two steps of 5 nm (44 inch lbs.) and 10 nm (89 inch lbs.). Install the evap purge solenoid together with its isolator and bolt by tightening the bolt to 10 nm (89 inch lbs.). Before reinstalling the MAP Sensor onto the Intake Manifold, apply engine oil to the MAP Sensor seal but maintain a light coat. Also prepare the solenoid and vapor pipe for attachment to their vent tube. Connect the pcv hose followed by the vacuum brake booster hose to the Intake Manifold rear. Guide the electrical harness into proper engine positioning then install the Knock Sensor harness to the Intake Manifold before reattaching MAP Sensor and Knock Sensor electrical connectors. Place the Throttle Body and fuel injectors back in their proper slots.

Install the lower intake manifold onto the engine block and cylinder heads, applying threadlock GM P/N 12345382 or equivalent to the threads of the lower intake manifold bolts.

Attach it to the throttle body and lower intake manifold, tightening the bolts and nut to 12 Nm (106 inch lbs.).

Attach the vent tube to the solenoid and vapor pipe.

Loosen and remove the intake manifold along with the intake manifold gaskets, discarding the old gaskets.

Ensure to install the sight shield retainer and the bolts, tightening them to 5 Nm (44 inch lbs.).

Connect the pressure cycling switch, surge tank switch, and MAF sensor, followed by connecting the engine harness clip to the wheelhouse splash shield and the clips to the studs on the front of the dash.

No, discharging the A/C refrigerant is not necessary.

If necessary, reposition and remove the brake booster vacuum hose and disconnect the EVAP canister purge tube and fuel feed line.

Remove the brake booster vacuum hose from the intake manifold nipple, the upper intake manifold cover nut, and the cover itself.

Tighten the bolt to 16 Nm (12 ft. lbs.) and the studs to 10 Nm (89 inch lbs.).

Install it if equipped.