Removal and installation camshafts (Mercedes-Benz S-Class W140)

Note: See also Section Timing Drive - General Information, Component Maintenance.

Removal

Removal camshafts
1 - Timing chain tensioner; 3, 5 - Camshaft sprockets; 6 - Timing chain; 25 - Key; 30 - Front cover; 42 - Upper guide arm

Removal camshafts
1, 4, 6, 7, 8, 11, 13, 14 — Camshaft bearing caps
2 — Inlet camshaft
3 — Exhaust camshaft

1. Set the piston of the first cylinder to the position 30° before TDC.

2. Remove the chain tensioner.

3. Remove the front cover (30) and the upper guide arm (42).

4. Mark the position of the camshaft sprockets relative to the timing chain (6) (arrow).

5. Unscrew the sprocket (3) of the exhaust camshaft.

6. Remove the timing chain (6) from the sprockets (5) of the intake camshaft.

7. Turn the camshafts with a wrench so that the camshaft cams of the second cylinder set the hydraulic compensator to the middle position.

8. Loosen the bearing cap bolts (1), (4), (6) and (7) of the exhaust camshaft and (8), (11), (13) and (14) of the intake camshaft. The camshafts cannot be turned while loosening or unscrewing the bearing cap bolts.

9. Unscrew the bolts securing the remaining covers and remove the camshafts.

Installation

Installing camshafts
2, 3, 5, 9, 10, 12 — Bearing caps
13, 14 — Camshafts

1. Check hydraulic lifters.

2. Lubricate all hydraulic lifters and bearing caps.

3. Install the camshafts in the bearing bed with the piston of the first cylinder at 30° before TDC.

4. Install covers (2), (3) and (5) of the exhaust camshaft and (9), (10) and (12) of the intake camshaft.

5. Tighten the camshaft bearing cap bolts to 21 Nm.

6. Install the remaining bearing caps and tighten the mounting bolts.

7. Install the exhaust camshaft sprocket and tighten the mounting bolts.

8. Install the chain on the camshaft sprockets according to the previously made marks.

9. Install the front cover and upper guide arm, timing chain tensioner.

10. Check the reference position of the camshafts.

11. The camshafts have a code designation on the third journal (arrows) (behind the bearing cap) or paint on the camshaft flange.

12. Bearing caps are marked. The bearing cap numbering is cast on the cylinder head. Bearing caps must be installed according to the digital code. The intake camshaft can be removed or installed together with the sprocket.