OEM 2003 Buick Century Intake Manifold

2003 Buick Century Parts Questions & Experts Answers

• Q: How to replace the lower intake manifold on 2003 Buick Century?

  A: Disconnect the negative Battery Cable, remove the upper Intake Manifold, left and right valve Rocker Arm covers, as well as disconnect engine coolant temperature (ECT) sensor electrical connector are required for the replacement of the lower Intake Manifold. Then, detach and pull the Fuel Injector and manifold absolute pressure (MAP) sensor wiring pairs, then eliminating the fuel pipe clip bolt and clip, the fuel feed and return pipes from the Fuel Injector rail, and the Fuel Injector rail itself. Take out the Power Steering Pump then reposition it, make a removal of the heater inlet pipe, nut and the heater inlet pipe along with hose from the lower Intake Manifold. Then we remove the lower Intake Manifold bolts to remove the lower Intake Manifold back. Remove the radiator inlet hose, thermostat bypass hose, and lower Intake Manifold before removing the lower Intake Manifold back. Remove the valve rocker arms, pushrods, and lower Intake Manifold gaskets and seals making sure they clean the surfaces of the gaskets and the mating surfaces of the lower Intake Manifold and the engine block, strip all the rtv sealant from the lower Intake Manifold and the engine block. Next, take out ect sensor, water outlet bolts, water outlet and Thermostat. For installation, begin with the installation of the Thermostat and the water outlet as well as ensuring that the bolts of the water outlet are tightened up to 25 nm (18 ft. Lbs) and the ect sensor is tightened to the same nm. Clean all gasket mating surfaces free of oil and foreign matter by using gm p/n 12346139 (Canadian P/N 10953463) or equivalent. Put the lower Intake Manifold gaskets, and apply a small drop of rtv sealer gm p/n 12346141 (CA P/N 89022195) or equivalent to the Intake Manifold joints blocking corners, and connect the drops with a bead of rtv sealer. Install the valve rocker arms and pushrods alongside the lower Intake Manifold, and ensure all bolts on the lower Intake Manifold are cleaned and free of foreign material by using new bolts only. Then torque the vertical lower Intake Manifold bolts to 7nm (62LB IN), then the diagonal bolts to same, the vertical to 13nm (115LB IN), and diagonal to 25nm (18LB FT). Install Thermostat bypass hose, heater inlet pipe nut (to 25 Nm (18 ft. Lbs.)), radiator inlet hose, heater inlet pipe and hose, and Power Steering Pump. Install the Fuel Injector rail, fuel return and feed pipes, fuel pipe clip and bolt (tightening the bolt to 8 Nm (71 inch lbs.)) and attach the Fuel Injector and MAP Sensor wiring harnesses. Lastly, connect the ect sensor electrical connector, then install the right and left valve Rocker Arm covers, upper Intake Manifold, reconnect negative Battery Cable and check for leaks.