Table of contents: Removal ↓ Front head (from the radiator side) ↓ Back head (from the engine…↓ Both heads ↓ Installation ↓
Caution! Wait until the engine has completely cooled down before starting work.
Removal
1. Drain the cooling system, including the engine block, (see Chapter Settings and ongoing maintenance). Remove the timing belt, timing gears and rear belt cover (see section Removal and installation the timing belt and timing drive gears). Also unscrew the bolts securing the cooling tract tubes to the rear of each cylinder head (from the transmission side) on the end plates of the camshafts.
2. Remove the intake manifold (see section Removal and installation the intake manifold) and move aside the injection injectors with the electrical wiring connected to them.
3. Remove the rocker arm assemblies (see section Removal, condition check and installation of rocker arm assembly) and valve lifters (see section Removal and installation camshafts and valve lifters).
4. Remove the exhaust manifolds (see section Removal and installation of exhaust manifolds).
5. Mark and disconnect all hoses and wires running from the timing side of the power unit.
Front head (from the radiator side)
1. Remove the spark plugs, distributor and coil (see Chapter Engine electrical equipment).
2. Remove the air conditioner compressor from its bracket and set it aside without disconnecting the refrigeration lines (see Chapter Cooling and heating systems). Tie the compressor with wire so that the refrigeration line hoses are not stretched.
Note: Access to the upper compressor mounting bolts is only possible after moving the assembly to the side.
3. Remove the compressor and generator bracket.
4. Remove the bracket securing the dipstick guide tube to the cylinder head.
Back head (from the engine compartment bulkhead side)
Disconnect the heater hoses and their brackets from the transmission side of the cylinder head.
Both heads
1. In several stages (1/4 turn per set) loosen the head bolts just enough to remove them by hand. Proceed in the reverse order to that shown in the illustration, starting with the small bolt located on the outside of the head.
2. Remove the washers placed under the bolt heads. All bolts, except the small one mentioned above, must be replaced without fail.
Note: Washers can be reused.
3. Remove the cylinder head from the engine block. If necessary, tap them with a hammer through a wooden block. If it becomes necessary to pry up a "stuck" head with a lever, try not to damage the mating surface.
Installation
1. Remove the old cylinder head gaskets. The mating surfaces of the heads and block must be absolutely clean and dry.
2. After scraping off the remaining gasket material and carbon deposits, wipe the surfaces with a rag soaked in acetone. The presence of traces of oil on the mating surfaces when installing the head can lead to a violation of the seal of the gasket fit and, as a result, the development of leaks. When processing the block, plug the cylinder holes with a rag to prevent small debris and various foreign objects from getting into them (as a last resort, vacuum the cylinders thoroughly).
3. Check the mating surfaces of the heads and block for deep scratches, burrs, and other damage. Minor defects can be removed with fine-grained sandpaper. In more serious cases, the only alternative is to resurface the components or replace them.
4. Using a tap of the appropriate size, run through the threaded holes for the head mounting bolts. After finishing the running, blow out the holes with compressed air. Clamping the bolts in a vice by the head one by one, go over their threads with a die - the presence of old sealant, dirt and corrosion products in the threads leads to a discrepancy between the actual tightening force of the fastener and the readings of the torque wrench indicator.
Note: When working with compressed air, do not forget to wear safety glasses!
5. Place the new seals onto the guide pins in the block.
6. Being careful not to displace the gaskets, carefully seat the heads on the block.
7. Lubricate the threads and undersides of the heads of the new mounting bolts with clean engine oil. Screw the fasteners into place and tighten the bolts finger tight.
Note: Don't forget to put washers under the bolt heads. The washers should be placed with the chamfered side facing up and the flat side facing the head.
8. Tighten the cylinder head bolts to the required torque, following the correct order (all but small outer ones).
Note: Bolts 4, 5, 12 and 13 are longer than the others!
9. Tighten the small bolts (one on the outside of each head) with a force of 9÷12 Nm.
10. Further assembly is carried out in the reverse order of dismantling the components.
11. Do not forget to fill the cooling system and replace the engine oil and oil filter (see Chapter Settings and ongoing maintenance).
12. Start the engine and check for signs of oil and coolant leaks. Check the ignition timing (see Chapter Settings and ongoing maintenance).