Mercedes S-Class W-140

1991-1999 of release

Repair and operation of the car

Mercedes S-Class
+ Mercedes-Benz cars of the class S (W-140)
+ Operation manual
+ Routine maintenance
- Engine
   Check of a compression in engine cylinders
   Check of the engine by means of the vacuum gage
   Belt of the streaming drive of auxiliary units
   - 6-cylinder petrol engines (M104.944 and M104.990/994)
      Cover of a head of the block of cylinders - installation details
      Removal and installation of the inlet pipeline with the resonator (except the engine 104.990)
      Final collector (except the engine M 104.990) - installation details
      Removal and installation of a head of the block of cylinders
      Removal and installation of a cover of a chain of the GRM drive
      The GRM drive - the general information, service of components
      Asterisk of a bent shaft - an installation detail
      Removal and installation of the regulator of the camshaft
      Removal and installation of camshafts
      Replacement of the directing plugs of valves
      Replacement of saddles of valves
      Removal and installation of pistons
      Replacement of piston rings
      Check of a condition of rods
      Check of a condition of a bent shaft
      Service of the block of cylinders
      Removal and installation of the pallet of a case of the engine
      The oil pump - installation details
      The oil level sensor switch - installation details, test data
   + 8-cylinder petrol engines (M119.970/981 and M119.971/981)
   + 12-cylinder petrol engines (M120.980/982)
   + 6-cylinder diesel engines (OM603.971)
   + 6-cylinder diesel engines (OM606.961)
+ Cooling systems, heating
+ Power supply system and release
+ Engine electric equipment
+ Gear shifting box
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


Removal and installation of pistons

Removal of the piston with a rod

1 — the Conrod cover
2 — the Rod
3 — the Bolt

4 — the Piston
5 — the Lock ring
6 — the Conrod finger

Installation of pistons

1 — the Conrod cover
2 — the Rod
3 — the Bolt

4 — the Piston
5 — the Lock ring
6 — the Conrod finger
7 — the Mandrel


1. Curtail covers of conrod bearings (1). The rod (2) and a cover (1) are marked together.
2. Remove the piston (4) and a rod (2) up. The direction of the movement is beaten out on the top part of the piston. On some versions of the shooter of the direction of the movement keeps the visibility not long because of wear of the piston; in this case the direction needs to be noted again.
3. Vypressuyte by means of the screw-driver a lock ring (5) also remove the piston from a rod.
4. Check gaps of piston rings.
5. Grease a piston finger (6) and the plug of a rod.
6. Install the piston (4) on a rod (2).
7. Press by hand a piston finger (6).
8. Insert a lock ring (5) into a groove in the piston.
9. Wipe cylinders, conrod necks, inserts and pistons (4) with oil.
10. Establish a mandrel (7) on piston rings.
11. Install pistons (4) in the direction of the movement.
12. Establish rods (2) and covers (1), having combined side tags.
13. Check and tighten bolts of fastening of conrod necks.
14. After assembly check gaps and ease of rotation.