Jeep Engines - Oljeep

4.2L IN-LINE 6 (CYLINDER HEAD) 299RemovalWarning! DO NOT remove the cylinder block drain plugsor loosen the radiator draincock with the system hot andpressurized because serious burns from the coolant canoccur.1.2.3.4.5.6.7.8.9.10. Disconnect the ignition wires and remove the spark plugs.11. Disconnect the temperature sending unit wireconnector and battery negative cable.12.13.Drain the coolant. Disconnect the hoses at thethermostat housing.Note: DO NOT waste reusable coolant. If the solutionis clean and is being drained only to service the engineor cooling system, drain the coolant into a cleancontainer for reuse.Remove the air cleaner.Remove the fuel pipe and vacuum advance hose.Remove the cylinder head cover. Refer to CylinderHead Cover Removal, in this section, for theprocedure.Remove the capscrews, bridge and pivot assembliesand rocker arms. Alternately loosen each capscrew,one turn at a time, to avoid damaging the bridge.Remove the pushrods. Retain the pushrod, bridges,pivots and rocker arms in the same order as removed tofacilitate installation in the original locations.Disconnect the power steering pump bracket. Set thepump and bracket aside. DO NOT disconnect thehoses.Remove the intake and exhaust manifolds from thecylinder head. Refer to the service manual for theproper procedures.If equipped with air conditioning, perform thefollowing:a. Remove the air conditioner compressor drive beltidler pulley bracket from the cylinder head.b. Loosen the alternator drive belt and remove thealternator bracket-to-cylinder head mounting bolt.The serpentine drive belt tension is released byloosening the alternator.c. Remove the bolts from the A/C compressormounting bracket and set the compressor aside.Remove the ignition coil and bracket assembly.Remove the cylinder head bolts, cylinder head andgasket.Cleaning and InspectionThoroughly clean the machined surfaces of the cylinderhead and block. Remove all gasket material and cement.Remove any carbon deposits from the combustionchambers and top of the pistons.Use a straightedge and feeler gauge to check the flatness of thecylinder head and block mating surfaces. Refer to 4.2L EngineSpecijkations, ‘Engine Assembly’ section of this chapter.InstallationIf the cylinder head is to be replaced and the original valvesused, measure the valve stem diameter. Only standard sizevalves can be used with a service replacement cylinder headunless the replacement head valve stem guide bores arereamed to accommodate oversize valve stems. Remove allcarbon buildup and reface the valves. Refer to ValveRefacing, ‘Camshaft and Valve Gear’ section of thischapter, for the proper procedure.1. Install the valves in the cylinder head usingreplacement valve stem oil deflectors (Figure 5-5).Refer to Installation-Cylinder Head Removed,‘Camshaft and Valve Gear’ section of this chapter, forthe proper procedure.2. Use all of the components from the original cylinderhead that are not included with the replacement head.DO NOT install the temperature sending unit untilcoolant is installed. This permits trapped air to escapefrom the cylinder block and head. Refer to the servicemanual for the proper procedure.Caution: DO NOT apply sealing compound on thecylinder head and block gasket surfaces. DO NOT allowsealing compound to enter the cylinder bore.3.4.5.6.7.8.9.Position the composition gasket on the cylinder blockwith the word TOP facing up.Install the cylinder head. Tighten the bolts in thesequence shown to 115 Nom (85 ft-lbs) torque(Figure 4- 18).Note: The head gasket is made of aluminum-coatedembossed steel and does not require the head bolts tobe re-tightened.Connect the battery negative cable.Install the ignition coil and bracket assembly.Install the spark plugs and connect the ignition wires.Tighten the spark plugs to 38 Nem (28 ft-lbs) torque.Attach the air conditioner compressor mountingbracket to the cylinder head, if removed.Install the intake and exhaust manifolds. Use thecorrect tightening sequence. Refer to the servicemanual for the proper procedures.