Mopar 4781577AD Plenum-Intake Manifold

You can Select Your Vehicle to check if 4781577AD fits your vehicle.

Relieve the fuel system pressure and disconnect the cable from the negative terminal of the battery. For the removal of the upper intake manifold, disconnect the electrical connector from the inlet air temperature sensor, the air intake tube from the throttle body, and remove the air filter housing. Disconnect the electrical connectors from the throttle position sensor and the MAP sensor, as well as the vacuum lines for the purge solenoid and PCV valve from the intake manifold. Label and disconnect the vacuum lines for the power brake booster, Leak Detection Pump, EGR transducer, and cruise control vacuum reservoir from the fittings on the intake manifold. Disconnect the accelerator cable and cruise control cable from the throttle lever and bracket, then disconnect the EGR pipe from the EGR valve. Remove the upper manifold support bracket bolts, the dipstick from the tube, and the upper intake manifold bolts, lifting the upper intake manifold from the lower intake manifold. For the lower intake manifold, disconnect the fuel lines at the fuel rail, drain the cooling system, and remove the heater supply and radiator upper hoses at the intake manifold. Disconnect the coolant temperature sensor and the fuel injector wire harness connector, then remove the lower intake manifold support bracket upper bolts and the fuel injector electrical harness connector. Remove the power steering reservoir bolts and set the reservoir aside without disconnecting the fluid line, then remove the lower intake manifold support bracket bolts and manifold bolts, taking care not to damage the gasket sealing surfaces. Carefully scrape all traces of gasket material from both the cylinder head and the intake manifold surfaces, ensuring not to nick or gouge the aluminum. Use a straightedge and feeler gauge to check the intake manifold mating surface for warpage; if any surface exceeds the limits, replacement or resurfacing is necessary. For installation, use a new gasket for the lower intake manifold, tightening the bolts in the recommended sequence to the specified torque. Install the lower intake manifold support bracket and tighten the bolts, then reverse the removal process for the remaining components. For the upper intake manifold, apply a 1/16-inch diameter bead of RTV sealant around the intake openings of the lower intake manifold for specific models, or install a new gasket for others, then install the upper intake manifold and tighten the bolts in the recommended sequence to the specified torque. Finally, refill the cooling system, run the engine, and check for leaks.

During installation, ensure all mating surfaces are clean, using gasket removal solvents if necessary. Use a gasket scraper to eliminate old gasket material, clean the surfaces with lacquer thinner or acetone, and remove any debris from the bolt holes.

Disconnect the EGR pipe from the EGR valve.

For the lower intake manifold, disconnect the fuel hose fitting, remove the ignition coil pack and bracket, disconnect the heater supply hose and ECT, and remove the fuel rail and injector assembly.

Carefully set the manifold in place, ensuring proper alignment of all openings and holes, then install the washers and nuts, tightening them in the recommended sequence to the specified torque.

Reinstall the remaining components in reverse order, change the oil and filter, refill the cooling system, start the engine, and check for leaks.

Remove the intake manifold support bracket and detach the EGR tube from the exhaust manifold.