OEM 2008 GMC Sierra 1500 Intake Manifold

2008 GMC Sierra 1500 Parts Questions & Experts Answers

• Q: How to replace the lower intake manifold on 2008 GMC Sierra 1500?

  A: The replacement process for a lower Intake Manifold begins by draining the cooling system contents. Begin by eliminating the fuel hoses along with Ignition Coil assembly components and the evaporative emission (EVAP) canister tube. Start by removing the heater hose clamp before disconnecting the heater outlet and inlet hoses. Detach the engine wiring harness electrical connector at the Throttle Body position and take off the connectors for the a/c pressure switch and a/c compressor clutch when vehicles have this equipment. The technicians should disconnect three important components: control port injector module, evap canister purge solenoid valve and manifold absolute pressure (MAP) sensor. Proceed to remove the engine harness clamp and covered electrical connector connections plus engine wiring harness bracket bolt before placing the engine wiring harness in its proper position. The positive crankcase ventilation (PCV) valve hose and power Brake Booster Vacuum Hose need to be removed. Next begin by releasing both radiator inlet hose clamps to remove the inlet hose from the Thermostat Housing before you detach the water pump inlet hose. The process to reach the front Intake Manifold bolt includes removing the Drive Belt while loosening the power steering (P/S) pump rear bracket nut before removing the p/s pump bracket nuts and bolts to slide the bracket forward. Take out the lower Intake Manifold bolts and remove the manifold along with discarding the existing gaskets. Perform necessary cleaning and inspection operations on the lower Intake Manifold. After applying a 4.0 mm adhesive patch to the cylinder head side of the Intake Manifold Gasket's ends, install the gasket upon wet adhesive then position it into place. Place the gasket inside its pins before distributing a 5 mm adhesive bead which should extend across both engine block tops and Intake Manifold gaskets. Before reinstalling the Intake Manifold use threadlock on the existing lower bolts which will be retained. Tighten the bolts in the specified sequence using a three-step method: the tightening process followed three distinct torque levels which started at 3 n.m and progressed to 12 n.m before reaching 15 n.m. Secure the p/s pump bracket to its proper position then fasten all associated bolts and nuts with a torque of 41 n.m. When reassembling the system replace the Drive Belt followed by the water pump inlet hose then the radiator inlet hose while making sure clamps maintain correct positions. Reinstall the PCV Valve Hose after connecting the power Brake Booster Vacuum Hose. Position the engine wiring and bracket then secure the bracket stud at 25 n.m followed by the rear bracket nut to 9 n.m while tightening the ground nut to 16 n.m. Embed the evap canister tube and reattach both the oil pressure sensor and the engine harness clamp. Connect the vehicle's components in this order: evap canister purge solenoid valve, map sensor, control port injector module and a/c connectors if required. As the last step, attach the engine wiring harness to the Throttle Body and perform the heater hose repositioning by installing the clamp. The installation process requires replacing fuel hoses with the Ignition Coil assembly before you fill your cooling system with fluid.