GM 12663489 Manifold, Intake

In order to remove the intake manifold, one has to first disarm the fuel system and the battery then take off the air intake duct. Next, remove the engine covers; remove the electrical connection to the throttle body, and also remove the electrical connections to the fuel injectors. Also, pulled the electrical connectors and took out the EVAP purge solenoid and MAP sensor, and rest of the wiring harness was placed aside after removing brackets. Unbolt and unbend the fuel rails and injectors this is not mandatory but will prevent damages on the injectors in the process of taking out the intake manifold. Remove any vacuum hoses connected to the intake manifold or throttle body and then loosen the intake manifold mounting bolts in a star-pattern with a 1/4-turn increment until they can then be removed. Slowly raise the intake manifold, ensure that there are no more bolts holding the manifold, do not pry the manifold off the heads as this will cause damage. During installation, it is advisable that the contact surfaces that belong to the cylinder heads and the manifold should be free from other residues of this gasket type, thus, the smell of old gaskets should not be eliminated with the help of a cutter. No debris should be allowed to remain on the surfaces and to achieve this, the surfaces should be wiped with a cloth that is soaked in safety solvent or brake cleaner and in case there is need to chase the threads in the bolt holes with a tap, compressed air should be used to clean the holes. Place the new gaskets on the suitable position on the intake manifold, making they are correctly positioned, and then mount the manifold gently. Use a medium strength thread locking compound on the bolt threads, install the bolts on the block and tighten them with the sequence suggested but do not over tighten in order to prevent gasket leakage. Last of all, the rest of the installation is done this way, and you need to check for lean vacuum after starting the engine at the Intake manifold joints.

To take off the intake manifold one has to disconnect the fuel system pressure and to separate the negative terminal of the battery cable. Then, take out the suspension cross brace and also the portion of the engine cover and finally, the plastic retainers linked to the engine cover to the intake manifold as well. On 2011 and previous versions remove the wiring of the MAF sensor, also remove the air intake duct then disconnect the throttle control motor wiring and the PCV pipe as well. At the rear of the engine, unplug the harness of each of the barometric pressure sensor, fuel injector, EVAP purge solenoid and the voltage intake manifold control valve motor, then remove the nut and bolt of the manifold brace. Take out the plenum bolts and raise the plenum off the intake manifold; of course, other connections should be undone at this point. Remove the fuel line from the rear of the fuel rail, then undo the bolts that secure the intake manifold to the cylinder heads and then lift the entire assemble with fuel rail and injectors still attached. For the 2012 and later models unplug brake booster vacuum hose and PCV valve, and Evap hose and all electrical connectors to the intake manifold. Now unbolt the intake manifold and assembly and position to dispense with the gasket and finally the remaining screws which holds the intake manifold to the upper intake manifold. To install, clean the mating surfaces of cylinder heads and manifold, also remove the old gasket material gently without scratching the surface and wipe them with a cloth soaked in solvent. New gaskets should then be placed on the lower intake manifold, fitted properly into place & then the manifold positioned. Give medium strength thread locking compound on the threads of the bolts, fasten the nuts in the correct Sequence and complete it in sequence reverse of the removal sequence. Last one begins with starting the engine and then using a vacuum gauge, search for vacuum leaks at the joints of the intake manifold.

To remove the intake manifold, the following must be done; disconnect the cable from the negative terminal on the battery and then release the fuel pressure. Further, un-bolt the air intake duct and, take off electrical connector of the throttle body along with the connectors of fuel injectors, EVAP purge solenoid and MAP sensor. Aside from the removed wiring harness connections, there are more brackets which should be detached from the upper part of the intake manifold and the wiring harness should be set aside. As a general procedure it is good that the fuel rails and injectors can be pulled out together so that there is no harm done to what is being worked on in this case the intake manifold. Remove all vacuum hoses that are connected on manifold or throttle body, then ease off the intake manifold bolts in reverse order of the lightening sequence in crawl-allity or a quarter turn till they are easy to remove fully. If the manifold is seized, use of a prybar can be gently used to separate the gasket surfaces thus releasing the gasket from its sealed position without damaging the sealing areas. After the manifold has been detached make sure that the mating surfaces in the cylinder head, block and the manifold are clean. Clean away all remains of the old gasket materiel carefully in a manner that does not harm the surfaces, and use safety solvent to wet a cloth. Hit on the threads with a tap to push the coarse threads into the holes further then use compressed air to blow out dirt. Align the new gaskets to the intake manifold so that they click into their appropriate position. Gently position the manifold and using medium strength locking compound; fit the bolts and tighten them strictly in the sequence to a certain torque value but not beyond the recommended torque. Last but not the least, do the installation in the very style it was pulled apart, start the engine and look for vacuum leaks particularly round the intake manifold joints.