Warning: This procedure must be performed when the engine is completely cool.
Note: In addition to the new gasket and other parts, tools and fixtures needed to complete this job, you will need a new plastic guide bushing during installation.
Removal
1. Disconnect the negative battery cable (Chapter 5, paragraph 1).
2. Remove the bolts securing the resonator support bracket from the front crossmember of the engine compartment. Loosen the two screws securing the resonator to the air flow meter and prechamber hoses. Then move the resonator away from the thermostat housing (Chapter 4).
3. Drain the cooling system (chapter 1).
4. Disconnect the coolant hose and coolant line/hose from the thermostat housing. Secure them away from the work area.
5. Unscrew the bolts of the heat-insulating casing of the exhaust manifold and remove both parts of the casing (see Fig. 7.5). When unscrewing the nut of the EGR system pipeline, the nuts of the exhaust manifold support, and the nuts of the fuel afterburning system, use penetrating oil.
6. Loosen the nut securing the EGR system pipeline to the manifold. Loosen the two screws securing the pipeline to the ignition coil bracket. Then loosen the nut securing the pipeline to the EGR system valve (Chapter 6).
7. The manifold can be removed together with the components of the fuel afterburning system. To do this, unscrew the bolts securing the filter housing and disconnect its vacuum hose. However, it is still easier to first remove the fuel afterburning system unit (Chapter 46, see Fig. 7.7).
8. Disconnect the oxygen sensor wiring connector to avoid strain on the oxygen sensor wiring. Remove the nuts to disconnect the exhaust downpipe from the manifold (Chapter 4).
9. Remove the nuts and lift off the manifold and gasket (see Fig. 7.9, a). When pulling the manifold out of the engine compartment, be careful not to damage adjacent components, such as the EGR line. If you are removing the manifold from an engine that is installed in a vehicle, additional space can be provided by removing the studs from the cylinder head. This will require a head with splines inside it (see Fig. 7.9, 6).
10. When installing, always install a new gasket on thoroughly cleaned components (see below). Do not attempt to use a used gasket.
Inspection
11. Use a scraper to remove the remains of the old gasket, as well as carbon deposits from the mating surfaces of the manifold and the cylinder head. If the gasket has leaked, check the manifold at a car repair shop for warping and, if necessary, send it for treatment of this surface.
Caution: When scraping, be careful not to scratch the aluminum cylinder head
12. Provided that the mating surfaces are clean and smooth, a new gasket will provide a gas-tight joint. Do not use sealants in areas upstream of the catalytic converter (in the direction of flow).
13. Note that the intake pipe is secured to the exhaust manifold with two bolts, each of which has a coil spring, a spring seat and a self-locking nut. When installing, tighten the nuts so that they rest against the shoulders of the bolts. This creates a spring force that prevents leaks through the joint (see Fig. 7.13, a, b).
14. Do not overtighten the nuts to eliminate leaks. If leaks are detected, replace the gasket and spring. The bolts are secured to the manifold with elastic clamps. If the bolts are damaged, they can be easily replaced (see Fig. 7.14).
Installation
15. Installation - in the reverse order of removal, taking into account the following:
- a) Install a new gasket onto the cylinder head studs. Install a new plastic guide bushing onto the stud closest to the thermostat housing (see Fig. 7.15). Do not install the manifold without this bushing.
- b) Install the manifold and tighten its support nuts by hand.
- c) Starting from the middle, tighten the nuts to the required torque (in three or four stages - see Technical requirements).
- d) Install the remaining parts in the reverse order of removal. Tighten all fasteners to the specified torque.
- d) Fill the cooling system (chapter 1).
- e) Start the engine and check for leaks in the exhaust system. After the engine has warmed up to normal operating temperature, check the coolant level.
