Valve Cover: Service and Repair
Removing and installing cylinder head covers - engine installed
Caution
When working on the engine, absolute cleanliness is essential! Lay removed engine parts on a clean base and cover them without fail. Even the smallest particles of dirt can block up oil bores.
- Disconnect the battery.
- Drain engine oil.
- Remove rear muffler on the corresponding side.
Removing cylinder head cover - cylinder bank 1 - 3
1. Remove the shield -1-. Unscrew 2 hexagon-head bolts M6 x 16. Pull out the shield to the side.
2. Remove the exhaust manifold. To do this, unscrew three M8 fastening nuts on the catalytic converter flange. Then unscrew six M8 screws from the cylinder head. If necessary, lever the exhaust manifold off the catalytic converter flange using a screwdriver.
Information
- In order to avoid damage to cables or hoses, the engine must not be lowered more than 40 mm.
3. Use a component jack to lower the engine by 30 - 40 mm. To do this, unscrew the two collar nuts (a/f 18) of the rear engine mounts and slowly lower the engine. Make sure that the hoses and cables are not damaged.
4. Remove holder for rear muffler -Item 2 in the upper Figure-. Disconnect cable plugs of the ignition coils and of the magnetic hydraulic valves. Unscrew 4 hexagon-head bolts: top 2 M8 x 30, bottom 2 M8 x 25, then remove the holder in downward direction.
5. Remove 3 ignition coils. Unscrew 6 M6 x 25 pan-head screws (hexagon socket a/f 5) and pull ignition coils out of spark-plug recess.
6. Remove 2 holders and 2 covers for the magnetic hydraulic valves. Unscrew 4 M6 x 20 pan-head screws (hexagon socket a/f 5), remove the connection cable for the hydraulic valves from the sheetmetal bracket and remove the holders. Pull off 2 covers for the hydraulic valves.
- A: Holder for camshaft adjustment valve (NVS)
- B: Holder for valve lift adjustment valve (VVS)
Cover for magnetic hydraulic valves in installation position with integrated seal
7. The cap of the stabilizer mount must be removed before the lower hexagon-head bolt -2- (Item 12 in the tightening sequence diagram) can be unscrewed. Unscrew the two M8 hexagon-head bolts -1- for this purpose.
Caution
When levering off the cylinder head cover, the cast lugs may break!
8. Remove the cylinder head cover. To do this, unscrew 20 M6 x 30 hexagon-head bolts from the cylinder head cover. Unscrew the two M6 x 20 hexagon-head bolts on the sides of the oil extraction pump. To release the cylinder head cover, raise the cover carefully at the two protruding cast edges with a slotted screwdriver. Remove the cylinder head cover of bank 1-3.
Figure shows upper cast lug.
Installing cylinder head cover - cylinder bank 1 - 3
Information
- The sealing surfaces of the cylinder heads and the cylinder head covers must be cleaned before the new sealant is applied. Avoid damage!
1. Clean sealing surfaces. Remove any sealant residue from the sealing surfaces on the cylinder head and the cylinder head cover thoroughly. Then rub down with a clean cloth soaked in a degreasing agent (e.g. acetone, solvent naphtha). Make sure that no sealant residue can enter the cylinder head.
2. Replace the 3 seals for the spark-plug recesses.
Only the following sealants may be used to seal the cylinder head cover:
- Drei Bond Silikon - type 1209 (beige)
- Loctite 5900 (black)
3. Fit a new [diameter] 45 mm cap into the bore of the exhaust camshaft dry.
Information
- Make sure that no sealant residue can enter the oil bores!
4. Apply a thin bead of sealant on the cylinder head cover -as shown in the Figure-. The bead should not be higher than 1.5 mm.
5. Fit 20 M6 x 30 hexagon-head bolts on the cylinder head cover and 2 M6 x 20 hexagon-head bolts for the oil extraction pump.
6. Refasten the cap of the stabilizer mount. Tighten the two M8 hexagon-head bolts -1- for this purpose.
Tightening torque: 23 Nm (17 ftlb.)
7. Insert 2 new green closure caps into the small bores on the cylinder head dry.
Information
- If the O-ring of the oil extraction pump needs to be replaced, insert the pump after fastening the cylinder head cover and then position the 4 hexagon-head bolts M6 x 20.
8. Tighten the 20 hexagon-head bolts in the specified tightening sequence with a torque wrench.
Tightening torque 13 Nm (10.0 ftlb.)
9. Tighten 2 or 4 M6 x 20 hexagon-head bolts of the oil extraction pump with a torque wrench.
Tightening torque 13 Nm (10.0 ftlb.)
Information
- Recheck to make sure that the closure caps are seated properly.
10. Fit 2 magnetic hydraulic valves (camshaft and valve lift adjustment), paying attention to the installation position. Carefully insert the magnetic hydraulic valve for camshaft adjustment into the bore of the cylinder head. When doing this, make sure that the cutout on the valve and the dowel pin of the cylinder head fit together. When fitting the valve for valve lift adjustment, make sure that the plug position is correct.
11. Fit 2 holders and 2 covers for the magnetic hydraulic valves: Screw in 4 M6 x 20 pan-head screws (hexagon socket a/f 5), insert the connection cable for the hydraulic valves into the sheetmetal bracket and fit the sheetmetal holder. Screw 2 covers for the hydraulic valves into place.
Tightening torque 10 Nm (7.5 ftlb.)
12. Fit 3 ignition coils: Tighten 6 M6 x 25 pan-head screws (hexagon socket a/f 5).
Tightening torque 10 Nm (7.5 ftlb.)
13. Fit holder for rear muffler -2-. Fit cable plugs of the ignition coils and of the magnetic hydraulic valves. Screw in and tighten 4 hexagon-head bolts:. top 2 M8 x 30, bottom 2 M8 x 25.
Figure shows engine side 1 - 3
Tightening torque: 23 Nm (17 ftlb.)
Information
- Fastening nuts, hexagon-head bolts and seals for the exhaust manifold must be replaced.
14. Fit the exhaust manifold. To do this, put three new M8 fastening nuts and a new metal seal on the catalytic converter flange. Then fasten the exhaust manifold on the cylinder head with six new M8 x 28 hexagon-head bolts and a new seal.
15. Tighten 9 M8 screw connections with the prescribed torque.
Tightening torque: 23 Nm (17 ftlb.)
16. Raise the engine again and then tighten the two collar nuts (a/f 18) on the rear engine mounts. Check hoses and cables for damage.
Tightening torque 85 Nm (63 ftlb.)
17. Fit shield: Tighten 2 M6 x 16 hexagon-head bolts.
Tightening torque 10 Nm (7.5 ftlb.)
18. Refit rear muffler.
19. Fill in engine oil and check the engine oil level (top up if necessary).
20. Connect the battery.
Removing cylinder head cover - cylinder bank 4 - 6
1. Remove the ground cable from the cylinder head. Unscrew 1 M8 hexagon-head bolt.
2. Pull the 2 cable plugs off the oil pressure sensor.
3. Remove the shield: Unscrew 2 M6 x 16 hexagon-head bolts. Pull out the shield to side.
Figure shows engine side 1 - 3
4. Remove the exhaust manifold. To do this, unscrew three M8 fastening nuts on the catalytic converter flange. Then unscrew six M8 screws from the cylinder head. If necessary, lever the exhaust manifold off the catalytic converter flange using a screwdriver.
Information
- In order to avoid damage to cables or hoses, the engine must not be lowered more than 40 mm.
5. Use a component jack to lower the engine by 30 - 40 mm. To do this, unscrew the two collar nuts (a/f 18) of the rear engine mounts and slowly lower the engine. Make sure that the hoses and cables are not damaged.
6. Remove holder for rear muffler. Disconnect cable plugs of the ignition coils and of the magnetic hydraulic valves. Unscrew 4 hexagon-head bolts: top 2 M8 x 30, bottom 2 M8 x 25, then remove the holder in downward direction.
7. Remove 3 ignition coils: Unscrew 6 M6 x 25 pan-head screws (hexagon socket a/f 5) and pull ignition coils out of spark-plug recess.
8. Remove 2 holders and 2 covers for the magnetic hydraulic valves: Unscrew 4 M6 x 20 pan-head screws (hexagon socket a/f 5), remove the connection cable of the hydraulic valves from the sheetmetal bracket and remove the holders. Pull off 2 covers for the hydraulic valves.
See Figures for cylinder bank 1 - 3
9. Remove 2 magnetic hydraulic valves (camshaft and valve lift adjustment), paying attention to the installation position. Pull both valves carefully out of the bores.
Information
- Pay attention to cleanliness without fail!
Caution
When levering off the cylinder head cover, the cast lugs may break!
10. Remove cylinder head cover. Repeat step No. 8 as with cylinder bank 1-3.
Installing cylinder head cover - cylinder bank 4 - 6
Information
- The sealing surfaces of the cylinder heads and the cylinder head covers must be cleaned before the new sealant is applied. Avoid damage!
1. Clean sealing surfaces. Remove any sealant residue from the sealing surfaces on the cylinder head and the cylinder head cover thoroughly. Then rub down with a clean cloth soaked in a degreasing agent (e.g. acetone, solvent naphtha). Make sure that no sealant residue can enter the cylinder head.
2. Replace the 3 seals for the spark-plug recesses.
Only the following sealants may be used to seal the cylinder head cover:
- Drei Bond Silikon - type 1209 (beige)
- Loctite 5900 (black)
Information
- Make sure that no sealant residue can enter the oil bores!
3. Apply a thin bead of sealant on the cylinder head cover -as shown in the Figure-. The bead should not be higher than 1.5 mm.
4. Insert 2 new green closure caps into the small bores on the cylinder head dry.
Information
- If the O-ring of the oil extraction pump needs to be replaced, insert the pump after fastening the cylinder head cover and then position the 4 M6 x 20 hexagon-head bolts.
5. Fit 20 M6 x 30 hexagon-head bolts on the cylinder head cover and 2 M6 x 20 hexagon-head bolts for the oil extraction pump.
6. Fit a new brown [diameter] 45 mm cap dry into the cylinder-head-side part of the exhaust-camshaft bore on the pulley side.
7. Tighten the 20 hexagon-head bolts in the specified tightening sequence with a torque wrench.
Tightening torque 13 Nm (10.0 ftlb.)
8. Tighten 2 or 4 M6 x 20 hexagon-head bolts of the oil extraction pump with 13 Nm (10.0 ftlb.) with a torque wrench.
Tightening torque 13 Nm (10.0 ftlb.)
Information
- Recheck to make sure that the closure caps are seated properly.
9. Fit 2 magnetic hydraulic valves (camshaft and valve lift adjustment), paying attention to the installation position. Carefully insert the magnetic hydraulic valve for camshaft adjustment into the bore of the cylinder head. When doing this, make sure that the cutout on the valve and the dowel pin of the cylinder head fit together. When fitting the valve for valve lift adjustment, make sure that the plug position is correct.
10. Fit 2 holders and 2 covers for the magnetic hydraulic valves: Screw in 4 M6 x 20 pan-head screws (hexagon socket a/f 5), insert the connection cable for the hydraulic valves into the sheetmetal bracket and fit the sheetmetal holder. Screw 2 covers for the hydraulic valves into place.
Tightening torque 10 Nm (7.5 ftlb.)
11. Fit 3 ignition coils: Tighten 6 M6 x 25 pan-head screws (hexagon socket a/f 5).
Tightening torque 10 Nm (7.5 ftlb.)
12. Fit holder for rear muffler -2-. Fit cable plugs of the ignition coils and of the magnetic hydraulic valves. Screw in and tighten 4 hexagon-head bolts: top 2 M8 x 30, bottom 2 M8 x 25.
Figure shows engine side 1 - 3
Tightening torque: 23 Nm (17 ftlb.)
Information
- Fastening nuts, hexagon-head bolts and seals for the exhaust manifold must be replaced.
13. Fit the exhaust manifold. To do this, put three new M8 fastening nuts and a new metal seal on the catalytic converter flange. Then fasten the exhaust manifold on the cylinder head with six new M8 x 28 hexagon-head bolts and a new seal.
14. Tighten 9 M8 screw connections with the prescribed torque.
Tightening torque: 23 Nm (17 ftlb.)
15. Raise the engine again and then tighten the two collar nuts (a/f 18) on the engine mounts. Check hoses and cables for damage.
Tightening torque 85 Nm (63 ftlb.)
16. Fit shield: Tighten 2 M6x16 hexagon-head bolts.
Tightening torque 10 Nm (7.5 ftlb.
17. Fit ground cable on cylinder head. Tighten 1 M8 hexagon-head bolt.
Tightening torque: 23 Nm (17 ftlb.)
18. Push the 2 cable plugs onto the oil pressure sensor.
19. Refit rear muffler.
20. Fill in engine oil and check the engine oil level (top up if necessary).
21. Connect the battery.
