Removal
Note: The procedure for removing the cylinder head with the intake and exhaust manifolds is given. This greatly simplifies the process of removing the head, but it is advisable to use a lifting mechanism.
Depressurize the fuel system.
Remove the ground cable from the battery. Remove the components of the engine air supply system.
Equalize the pressure in the fuel tank by removing the filler cap. Then unscrew the fuel supply and return pipes. Remove the accelerator cable from the throttle. Remove the auxiliary drive belt.
Remove the power steering pump. Remove the three screws securing the wiring harness at the rear of the manifold. Release the wiring harness retaining bracket and disconnect the large electrical connector (near the fuel pressure regulator). Release the electrical connectors on each side of the ignition coil, and one connector from the lower front of the thermostat housing to disconnect the coolant temperature sensor (see Fig. 2C.38, 2C.39).
Label and disconnect the vacuum hoses as follows:
- one from the back of the throttle body (no need to disconnect the second hose going to the fuel pressure regulator)
- one from the connection on the left end of the intake manifold
- brake booster hose
Remove the bolts from both sides of the exhaust manifold heat shield.
Remove the bolt securing the air cleaner housing to the engine/gearbox front mount, then disconnect the vacuum hose.
Drain the coolant from the cooling system. Disconnect all coolant hoses from the thermostat housing (see Fig. 2C.40).
Remove the two nuts securing the exhaust pipe to the front of the exhaust manifold and disconnect the oxygen sensor. Support the weight of the engine using a jack with a wooden block.
Remove the timing belt, both camshafts and hydraulic tappets. Remove the inner timing belt shield.
Evenly and gradually in a certain sequence, loosen the ten cylinder head mounting bolts (Torx T55 key). Remove the cylinder head and head gasket.
Preparing the head for installation
The mating surfaces of the cylinder head and block must be completely clean. Use a hard plastic or wooden scraper to clean them. Be careful when cleaning, as the aluminum alloy is very easy to damage. Check that carbon deposits have not entered the oil and water passages, this is especially important for the lubrication system, as carbon deposits can block the supply of oil to the engine components. Clean the passages if necessary. Check the mating surfaces of the cylinder head and block for nicks, deep scratches and other damage. If the defects are small, they can be removed by mechanical treatment, but if the defects are significant, the parts must be replaced.
Using a metal ruler and feeler gauge, check the flatness of the mating surfaces.
Clean the bolt holes in the block. Driving a bolt into an oil filled hole can cause the block to burst due to hydraulic pressure.
Installation
Wipe the mating surfaces of the cylinder head and block.
Check that the new cylinder head gasket is the same type as the original and that the "TOP" (or "OBEN") marking is facing upwards. Position the new cylinder head gasket on the cylinder block surface on the guide pins. Check that the holes are correctly aligned with the cooling and lubrication system passages (see Fig. 2C.41).
To prevent the possibility of valve and piston contact, turn the crankshaft so that the piston of the first cylinder is positioned 20 mm below the TDC position.
To make it easier to fit the heavy head into place, make a pair of M10 threaded standoffs, about 90 mm long, with a slot for a screwdriver in one end (you can use two old head bolts, having previously cut off the bolt heads and sawed a slot for a screwdriver). Screw these standoffs into holes in diagonally opposite corners of the cylinder block surface. With the screwdriver slots facing up, so that they can be unscrewed after installing the head. The standoffs should protrude above the gasket by 70 mm.
Install the head by sliding it down the posts and position it on the guide pins. Unscrew the posts.
Install new cylinder head bolts and tighten them by hand.
Gradually and in a certain sequence, tighten the head mounting bolts in several stages (see Fig. 2C.42, 2C.43).
Install hydraulic lifters, camshafts, camshaft oil seals and pulleys.
Temporarily install the crankshaft pulley, and rotate the crankshaft clockwise to set the pulley marks 8 position TDC piston number one cylinder. Install the toothed belt and covers. checking the alignment of the camshaft and adjust the tension of the toothed belt. Further installation is carried out in the reverse order of removal.