Camshaft: Service and Repair

Camshafts

Special tools, testers and auxiliary items required

• Puller (T40001)

• Retainer (3036)

• Thrust Piece (3334)

Removing

• The sealing surfaces on the bottom of the guide frame and on the top of the cylinder head must not be worked.

• Camshaft bearings are integrated in the cylinder head and in the guide frame. Before removing the guide frame, tension on the toothed belt must be released.

• If the guide frame was loosened, the camshaft seal and the sealing cap must be replaced.

- Remove the camshaft adjuster. Refer to => [ Camshaft Adjuster ] Camshaft Adjuster.

- Remove the toothed belt. Refer to => [ Toothed Belt ] Service and Repair.

- Loosen the camshaft sprocket bolt approximately 10 mm (use the retainer (3036) ).






- Remove the camshaft sprocket using the puller (T40001) and the claws (T40001/6) and (T40001/7).






The puller (T40001) supports itself on the bolt - arrow -.

- Remove the bolt and camshaft sprocket.

- Remove the rear toothed belt guard from the cylinder head.

- Loosen the bolts for the guide frame evenly working from the outside towards the inside and remove the guide frame.

- Carefully remove the camshafts upward and place them on a clean surface.

- Remove any old sealant from the groove in the guide frame as well as from the sealing surfaces.






- Make sure that no dirt or sealant residue can get into the cylinder head.

Installing

• The sealing surfaces must be completely free of oil and grease.

• The pistons must not be positioned at Top Dead Center (TDC).

• Make sure that all roller rocker arms make contact correctly on the valve stem tips.

- Lubricate the running surfaces of both camshafts.

- Place the camshaft carefully into the camshaft bearings in the cylinder head. The camshaft lobes - A - for cylinder 4 must face each other.






- Apply a light sealant bead of sealant (D 154 103 A1) evenly in the groove in the guide frame as shown in the illustration.






• The sealant must not be applied too thick. Wipe off any excess sealant with a lint-free cloth, if necessary.

• Placing the guide frame in place and tightening the bolts it should occur without interruption, since the sealant begins to harden immediately when the sealing surfaces come into contact.

• Note the expiration date of the sealant.

- Place the guide frame onto the cylinder head.

- Gently tighten the new bolts from working from the inside toward the outside in several stages.

- Tighten the bolts to 8 Nm + an additional 90° turn in the sequence shown.






- Drive the sealing cap in approximately 1 to 2 mm using the thrust piece (3334).

- Install the camshaft seal. Refer to => [ Exhaust Camshaft Seal ] Service and Repair.

- Install the rear toothed belt guard.

- Insert the woodruff key into the camshaft.

- Insert the camshaft sprocket. To tighten the bolt, counter hold the camshaft sprocket using the retainer (3036).

Tightening specification: Refer to => [ Valvetrain Overview ] Service and Repair.






• When turning the camshaft, the pistons may not be at TDC for any cylinder. Valves/pistons may be damaged.

• Be sure the woodruff key is properly seated.

- Install the toothed belt. Refer to => [ Toothed Belt ] Service and Repair.

- Install the camshaft adjuster. Refer to => [ Camshaft Adjuster ] Camshaft Adjuster.

- Install the cylinder head cover. Refer to => [ Cylinder Head Cover ] Cylinder Head Cover.

Further installation is in the reverse order of removal.