The heads should further be removed when the engine is cold to avoid the heads warping. This procedure is quite demanding and perhaps it is recommended that the engine be pulled out of the vehicle, placed on an engine stand As with a number of other procedures, this one could however be done in-vehicle provided adequate tools and or expertise is applied. The rocker arms and the valve lash adjusters have to be pulled out before and any repair work on the cylinder heads or timing and jackshaft chains. Start with the isolation of one of the battery terminals followed by the evacuating of all the cooling system, and finally extraction of the engine from the car. Fourth, time to take out the intake manifold, number the connectors on the fuel injectors and then unplug and unbolt the exhaust manifolds. You can now eliminate the Serpentine Belt and tensioner, and the rocker arms and the valve lash adjusters. For the right cylinder head, you need to detach alternator and lower and upper mounting brackets, upper radiator hose, coolant bypass hose and engine coolant temperature sensor. Remove rear engine mount bracket, also remove the accessory bracket and thermostat housing along with the bolts that are used to hold the engine wiring harness. On the left cylinder head, remove the radio capacitor, and the ignition coil assembly, and the accessory bracket voltage. Take off the hydraulic chain tensioner and the bolts used in the fixing of the camshaft sprocket and chain cassette. Do the same thing for the right cylinder head and make a particular note of the fact that the sprocket bolt for the right cylinder head is left hand threaded. Loosen the cylinder head bolts in the reverse order that was used while tightening with a pry bar use to loosen the gasket seat from the cylinder head and lift it up, the cylinder head should be placed on wooden blocks. A major that has to be observed prior to installation of the bolts is that both the mating surfaces must be clean, free from damage and the threads within the bolt holes chased. Place the new gaskets as required, fit the cylinder heads and torque the new cylinder head bolts in the right manner. Place the camshaft sprocket in its hole and check it if it is free to rotate and place the camshaft chain tensioning tool. Turn the engine to position cylinder No.1 to the TDC and tighten the crankshaft holding tool and put in the camshaft holding tool. Torque up the camshaft sprocket bolt, and fit on the hydraulic tensioners. Last of all, fit the rocker arms and the hydraulic valve lash adjusters on then perform the reverse of the steps outlined in removal, replace the engine oil and filter and turn on the engine and inspect for leaks.