Removing and installing chain tensioner - RA05001203100X(05-3100)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

Preceding work:

Poly V-belt removed (13-3420) .

Air cleaner with mass air flow sensor, right, removed (09-0015) .

Intake air scoop, right, removed (09-0060) .

Secondary air pump removed (14-7251).

Operation no. of the operation texts and work units or standard texts and flat rates 05-7800, 7801

Fig 1: Identifying Chain Tensioner Remove/Install Components

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Crankshaft	turn to 30° after TDC on 1st cylinder.
Plug (1)	loosen approx. one turn.
Chain tensioner	unscrew completely, remove.
If the chain tensioner housing (14) has been loosened, it must be removed, because the thrust bolt (10)	has engaged in the locking spring (9) in the thrust direction.
Filler pin (7) and pressure spring (8)	unscrew, remove (step 4).
Thrust bolt (10)	press out of chain tensioner housing (14) in thrust direction together with catch spring (9) (item 5).
Chain tensioner housing (14)	install with sealing ring (15), tighten to 50 Nm (item 6).
Thrust bolt (10)	slide in together with catch spring (9), pressure spring (8) and filler pin (7) (item 7).
Plug (1)	install with sealing ring (5), tighten to 40 Nm (item 8).
Leakage	check.

TIGHTENING TORQUES IN NM

Plug, chain tensioner	40
Chain tensioner housing in timing case cover	80

Special tools

Fig 2: Identifying Special Tool (001 589 66 21 00 00)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Fig 3: Identifying Special Tool (001 589 65 09 00 03 07 32)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

COMMERCIALLY AVAILABLE TOOL

Pin wrench insert 10 mm, 1/2" drive

e.g.

Hazet
D 5630 Remscheid
Order no. 985/10

NOTE: Improved noise characteristics in engine speed range 900 - 1200 rpm when engine is at normal operating temperature as a result of modified chain tensioner.

Pressure pin (10) 1.1 mm dia. control bore (identified by 3 grooves on 14.2 dia.).

Compression pin (8) wire gauge 0.7 mm (was 0.6 mm).

Standard as of August 1991.

Engine 120.980-12-003 128

120.981-12-000 068

Fig 4: Sectional View Of Chain Tensioner Housing

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Removal, installation

Turn crankshaft to 30° after ignition TDC on 1st cylinder (arrow).
Loosen plug (1) approx. 1 turn.
Completely unscrew chain tensioner and remove.

Fig 5: Locating 1st Cylinder Position
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Remove plug (1) with sealing ring (5). Remove thrust spring (8) together with filler pin (7).
Press out thrust bolt (10) together with catch spring (9) in thrust direction. Clean parts.
Screw in chain tensioner housing (14) with new sealing ring (15) and tighten to 50 Nm.
Installation note

Stick seal (15) with grease to the chain tensioner housing (14) so that it remains centered on the guide shoulder.

Tightening torque 80 Nm.

Fig 6: Exploded View Of Chain Tensioner Housing
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Insert thrust bolt (10) into installed chain tensioner housing together with installed catch spring (9) and pressure spring (8) with filler pin (7).

Fig 7: Inserting Thrust Bolt Into Installed Chain Tensioner Housing
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Screw plug (1) into installed chain tensioner housing (14) with new sealing ring (5) and tighten to 40 Nm.
Allow engine to run and check for leakage.

Fig 8: Identifying Sealing Ring And Chain Tensioner Housing
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.