GM 12631023 Manifold, Intake

Before the intake manifold can be removed, one has to release the fuel system pressure and join the negative terminal of the battery. Pull down the suspension crossbrace off from the top of the front struts and the covers of the engine. For the 2005 through 2011 models with 2.6L and 3.6L engines first remove the wiring from the MAF sensor as well as the air intake duct, next disconnect the throttle control motor wiring connector as well as the PCV pipe. At the rear of the engine remove the wiring connection from the barometric pressure sensor, fuel injector harness, EVAP purge solenoid and the variable intake manifold control valve motor bolts; manifold brace bolts, the plenum bolts. Remove the plenum from the intake manifold disengaging all the remaining connections and detach the fuel line connected to the rear end of the fuel rail. Take out intake manifold bolts connect to the cylinder heads and lift of the intake manifold from the engine. On 3.0L engines remove brake booster vacuum hose, the PCV valve, the EVAP hose and all electrical connections to the intake manifold before removing the assembly. In 2012 and later models, remove the PCV tube and EVAP hose, the fuel rail shield, and any electrical connectors that you can see before popping up the intake manifold and its gasket. When tightening let the mating faces be clean, when replacing gaskets, eliminate the old gasket material gently and replace with fresh gaskets in the right manner. Then place the manifold in correct position, add the thread locking compound to the bolt and then tighten the bolts in correct pattern and to the torque value. Last but not the least; check the coolant level, engage the engine and look for the vacuum leaks at the joints of the intake manifold.

To take off the intake manifold first free the fuel pressure and disconnect the ground cable for the battery. Further, take off the engine top front cover bolts and the cover and in the same manner take off the rear cover bolts and the rear cover. Unplug the electrical connector leading to the throttle body, to have access to the air filter and air intake assembly. Loosen the electrical connectors including the fuel injectors, EVAP solenoid, MAP sensor and the throttle body sensors and mark them so that they can be easily fitted back as they are. Remove the knock sensor connectors and remove the ground straps at the rear of the right cylinder head, and any other harness brackets off the top of the intake manifold. Take out the fuel rails and injectors with the injectors citing the reason that it reduces chances of damaging the injectors. Remove the connections of the coolant hoses and any vacuum hoses linked to the intake manifold or throttle body. Tighten or loosen the intake manifold mounting bolts, in a diagonal sequence, by a quarter turn, till you can easily remove the bolts with your hands; use a prybar to remove the intake manifold gasket if necessary but do not mar the gasket surfaces. Take out the intake manifold, and be sure to note and disconnect any components still connected if any. When reinstalling these parts make sure that the surfaces of the cylinder heads, block and manifold are spotlessly clean, no trace of the old gasket compound should be left without having to scratch off the metal. With safety solvent moistened cloth clean the surfaces and then clean the debris with vacuum cleaner. Turn of the respective threads in the bolt holes with a tap before blowing compressed air over the area to remove any debris. Put the new gaskets in the appropriate area on the intake manifold that will allow them to interlock properly. Lay the manifold in easily, Schlage greying over the internal thread of the bolt before screwing it in the recommended sequence and tightened to the maximum permissible torque but not exceeding it. The rest of the procedure is a reverse order of the removal and includes the inspection of the coolant level and the start of the engine to look for the presence of the vacuum leaks, especially at the intake manifold gaskets.

First, disengage the locking tab on the oil filler spout with a small screwdriver and rotate it counterclockwise to remove.