GM 12575084 Manifold Assembly, Lower Intake

Unfasten the wire from the negative battery terminal. Take away the air filter casing and also the inlet air duct. Disconnect any electrical connector which will cause obstruction to intake manifold removal, including throttle body solenoid, intake manifold runner control solenoid and others. Separately remove vacuum hoses from vacuum solenoid and intake manifold runner control vacuum actuator. Separate clamps on all of the runners at the upper intake manifold. Detach EGR pipe from top intake manifold. Undo screws that hold down upper intake manifold then lift it up out of engine bay. After lifting slightly the upper intake manifold, clamp off as well as disconnect coolant hose from throttle body first. Carefully place in position the upper intake manifold. Seat in place all bolts holding upper intake manifold into position. When bolting is complete have them torqued to specifications required for each bolt type specifically for this job.Installation steps that follow are basically the reverse of procedures applied above when dismantling unit or a part.Check coolant level; add if necessary.Reconnect battery cables, switch on ignition key and observe keenly for any leakage.Remove lower intake manifold by following these simple steps: Remove upper intake manifold along with its manifolds.Just before taking out rail and injectors make sure fuel system is depressurized.Take away attaching screw plugs for lower tank.Extract spacer located between engine block and lower tank.Clean off O-rings left behind on spacer upon removing it.Clean surfaces of both-spacer and engine block.Use lacquer thinner or acetone to clean gasket faces.When working on cylinder heads and engine blocks, hang shop rags over open areas.Turn on vacuum cleaner's pipe to suck in dirt dropping inside cylinders.Sporadically use suitable sized tap to perform a cleanup exercise within bolt holes by blowing dust off as much as possible using compressed air starting with new O-rings which should be installed into spacer.Inserting plate onto block should be done with care.Setting the lower intake manifold in its place without moving it or disturbing the spacer that came into contact with the engine block.Tighten all bolts attaching lower intake manifold to specified torque.Put some thread locking compound on threads of each bolt used for securing lower intake manifold. Just do everything in reverse order.Check coolant level and refill if required.Reconnect battery cables, switch on ignition key and observe keenly for any leakage.

Negative battery terminal cable is disconnected. Throttle body is removed. Any electrical connectors that would interfere with manifold removal are disconnected. Open the wiring harness clips and detach all wiring harnesses from the manifold. Manifold hoses may be marked prior to removal, ensuring correct reassembly. Then, remove the dipstick tube mounting bolt and position the dipstick to the side. After that, intake manifold mounting bolts and nuts have to be removed. The intake manifold can now be lifted from the engine compartment.Install a new gasket if necessary; otherwise, no need for replacingthe intake manifold gasket in case it is not damaged during theremoval process. The surfaces of both manifold and cylinder head must remain clean before installation. Putting the manifold over the studs on the cylinder head follows this step. Install bolls and nuts finger-tight and then tighten them. Bolls should be tightened to a specific torque value starting fromthe center bolls to ends until they are firmly tightened throughout.Therest of installation is just doing the opposite of removing steps.Reconnecting battery. Run engine check for vacuum leaks.