OEM 2005 Buick Century Intake Manifold

2005 Buick Century Parts Questions & Experts Answers

• Q: How to replace the lower intake manifold on 2005 Buick Century?

  A: To remove the lower Intake Manifold, you have to disconnect the negative cable on the battery and then take out the upper Intake Manifold, the left and the right valve Rocker Arm covers, and the engine coolant temperature (ECT) sensor electrical connector. Then, disconnect and remove the Fuel Injector and manifold absolute pressure (MAP) sensor wiring harnesses, remove the fuel pipe clip bolt and clip and fuel feed and return pipes to the Fuel Injector rail and, at last, fuel injector rail. Replace the position of the Power Steering Pump after removing it from the front engine cover, and remove the heater inlet pipe nut and heater input pipe with hose from the lower Intake Manifold. This requires the removal of the lower Intake Manifold, valve rocker arms, pushrods and gaskets after removing the radiator inlet hose, thermostat bypass hose, and lower Intake Manifold bolts as well. Clean and remove all rtv sealing from the lower Intake Manifold and engine block and remove the ect sensor, water outlet bolts, and water outlet then the Thermostat. Installation begins with installation of the Thermostat and water outlet, water outlet bolts to 25 nm (18 ft. Lbs.), ect sensor to the same torque. Applying an 8-12mm ( .08 - .11 inch) bead of rtv sealer, gm p/n 12346286 (Canadian P/N 10953472) or equivalent along each ridge where the front/rear of the lower Intake Manifold make contact with the engine block, then install the lower Intake Manifold gaskets, valve rocker arms, and the pushrods prior to installing the lower Intake Manifold. It's necessary to put on the sealant gm p/n 12345382 (Canadian #10953489) to all the bolts' threading with vertical bolts firstly screwed tighter than diagonal ones. Torch the Intake Manifold bolts (center) and bolts (corner) tighten the center lower Intake Manifold bolts to 7 nm (62 inch lbs.) then corner bolts t o 7 nm (62 inch lbs.) then re tightening center bolts to 13 nm (115 inch lbs.) corner bolts to 25 nm (18 ft.lbs.). Replace the Thermostat bypass hose, heater inlet pipe nut (wide up to 25 Nm (18 ft. Lbs.), if appropriate), radiator inlet hose, heater inlet pipe with hose, and Power Steering Pump. Install Fuel Injector rail, fuel return, feeder pipes, fuel pipe clip & bolt(screws tightly to 8 Nm (71 inch lbs.)), and reconnect Fuel Injector and MAP Sensor wire harnesses, and ect sensor electrical connector. Lastly, mount the right & left valve Rocker Arm covers, upper Intake Manifold, reconnect negative cable and check for leaks.