4-cylinder in-line engine
Removal
1. Remove the air filter cross-hose by loosening the clamps.
Fig. 5.17. Removing the cylinder head cover: 1, 3 – bolt; 2 – bushing; 4 – spark plug tip; 5 – hose; 6 – side cover; 7 – gasket; 8, 9 – cover
2. Disconnect hose 5 (Fig. 5.17) of the engine crankcase ventilation system from the cylinder head cover.
3. Disconnect cover clamp 6 and remove it by moving it upwards.
4. Unscrew bolt 1, then remove cover 9 with sleeve 2.
5. Remove the spark plug caps.
6. Disconnect the oxygen concentration sensor wire.
7. Loosen the cylinder head cover mounting bolts.
Please note: The bolts are of different lengths, so mark their installation locations.
8. Remove cover 8 with gasket 7.
Installation
9. Check the technical condition of the cover gasket: it should not have porosity or crushed areas. Install cover 8 with gasket 7 on the cylinder head.
(Article was borrowed from the website: mercedesman.ru)
Attention! Pay attention to the correct installation of the gasket on the side of the rear grooves.
10. Tighten the cover mounting bolts evenly to a torque of 10 Nm.
11. Secure the oxygen concentration sensor wire.
12. Install the spark plug caps.
13. Install and bolt the remaining covers.
14. Connect the crankcase ventilation hose and secure it with a clamp.
15. Install the air filter cross pipe.
16. Start the engine and warm it up to operating temperature.
17. Check the cylinder head cover for leaks. Pay particular attention to the rear recesses and spark plug recesses.
6-cylinder V-engine
Removal
1. Disconnect the connector from the air flow meter sensor.
2. Remove the air filter resonator.
3. Remove the air filter.
Fig. 5.18. Removing the cylinder head covers of a 6-cylinder V-engine: 1 – inlet pipe; 2-pin connector; 3, 5 – ignition coil; 4 – spark plug tip
4. Unscrew the inlet pipe 1 from the cover (Fig. 5.18), disconnect it from the throttle assembly and remove it together with the mass air flow sensor.
For models with automatic transmission:
5. Disconnect the transmission oil level indicator tube.
For all models:
6. Disconnect the fastening of ignition coils 3, 5 to the cylinder head covers.
7. Remove the 4 spark plug caps.
8. Disconnect the vacuum hoses facing the intake manifold from the cylinder head covers.
9. Disconnect the engine crankcase ventilation hose from the rear end of the left cylinder head cover.
10. Loosen the cylinder head cover mounting bolts and remove them with the sealing gasket.
Installation
11. Install the cylinder head cover with the gasket and tighten the mounting bolts crosswise to a torque of 10 N·m. Check the correct installation of the gasket by touching it with your fingers.
12. Connect the engine crankcase ventilation hose to the rear of the left cylinder head cover.
13. Connect the vacuum hoses to the cylinder head covers.
14. Tighten ignition coils 3 and 5 to a torque of 8 Nm.
15. Fasten the 4 spark plug tips to the cylinder head covers according to their markings and connect to the ignition coils.
For models with automatic transmission:
16. Screw on the guide tube of the oil level indicator in the gearbox.
For all models:
17. Install the air filter.
18. Attach the air filter with the intake pipe, mass air flow sensor and throttle assembly to the cylinder head cover.
19. Connect the connector to the mass air flow sensor and install the resonator.