Withdrawal
Allow the engine to cool completely, then depressurize the fuel system for fuel injected engines (see chapter Supply system).
Disconnect the negative battery cable.
If your car's radio is equipped with an anti-theft system, make sure you have entered the correct code before disconnecting the battery.
If, after connecting the battery, the inscriptions on the instrument panel appear in the wrong language, refer to Section Anti-theft audio system and instrument panel language, for instructions on how to set the desired language.
1. Drain engine coolant (see chapter Car maintenance) to a level below the intake manifold. If the cooler is still in good condition, it can be used again.
2. On fuel injected engines, loosen the hose clamp and disconnect the large air intake hose from the throttle body. It may be necessary to remove the entire air cleaner/inlet hose assembly to give more room to work (see Chapter Supply system).
3. On carbureted engines, completely remove the air cleaner assembly (see chapter Supply system).
4. Disconnect the coolant hoses from the throttle body/inlet piping as provided.
5. Disconnect the throttle cable and, if provided, the tempostat drive cable (see chapter Supply system).
6. Remove the EGR valve and line, where provided (see chapter Engine management and emission control systems).
7. At this stage, on M40 engines, the upper part of the intake manifold should be removed by releasing the bolts and nuts. Remove the pads.
8. On engines with a fuel injection system, disconnect the vacuum hose from the fuel pressure regulator and disconnect the electrical connectors from the fuel injectors (see chapter Supply system).
9. Disconnect the fuel lines from the fuel line or carburetor as provided (see chapter Supply system).
10. On M40 engines, unbolt and remove the support bracket from the bottom of the intake manifold.
11. Disconnect any remaining hoses and wires between the intake manifold/throttle body assembly and the engine or chassis.
12. Give the bolts and / or nuts securing the pipeline to the cylinder head using a replaceable head, a ratchet and a long collar (M20 engines).
13. Start at the ends and move towards the middle, loosening each nut in turn, a little at a time, until they can be given away by hand. When removing fasteners, support the pipeline so that it does not fall.
The piping can be removed without removing the throttle body, injectors, vacuum/thermal valves, fuel pressure regulator, or carburetor. If you are installing a new piping, move all of these components (see chapter Supply system) on a new pipeline before installing it on the cylinder head.
14. Move the tubing up and down to break the gasket sealant, then remove it from the head and then remove the gasket.
Installation
1. Remove the old gasket, then carefully scrape off all traces of the old gasket material from the tubing and head mating surfaces. Be very careful not to damage or scratch the soft aluminum surfaces. Special solvents for removing gaskets are commercially available. Make sure surfaces are perfectly clean and free of grease.
2. Check the pipeline for signs of corrosion (where the cooler goes), cracks, deformations and other damages. Cracks and deformations usually appear near the surface of the gasket, around the holes for the gap adjustment screws. If such defects are found, return the pipeline for repair (or replace if necessary).
3. When installing piping, always use a new gasket. Where one side of the gasket has a graphite surface, it should face the cylinder head.
4. Fit the nuts and bolts and tighten them gradually, starting from the center and moving towards the ends, achieving the required torque.
5. Perform the rest of the installation procedure in the reverse order of removal. On M40 engines, replace the gaskets between the top and bottom of the pipeline.