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)
   - 8-cylinder petrol engines (M119.970/981 and M119.971/981)
      Covers of heads of the block of cylinders - installation details
      Removal and installation of the inlet pipeline
      Removal and installation of a final collector
      Removal and installation of heads of the block of cylinders
      Removal and installation of covers of a chain of the GRM drive
      Replacement of a chain of the GRM drive
      Check of phases of gas distribution
      The GRM drive - the general information, service of components
      Removal and installation of the regulator of phases of gas distribution
      Removal and installation of camshafts
      Check and adjustment of control position of camshafts
      Removal and installation of valves
      Replacement of the directing plugs of valves
      Replacement of rings of saddles of valves
      Removal and installation of pistons
      Designation and sizes of pistons
      Check of a condition of rods
      Check of a condition of a bent shaft
   + 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



1. Turn off conrod covers and remove pistons together with rods.
2. Check bolts of fastening of conrod covers.
3. By means of the screw-driver remove a lock ring and a vypressuyta a piston finger.



1. If the piston is damaged, check a gap and an axial beating of piston rings.
2. Oil a piston finger and plugs of rods.
3. Install the piston so that the arrow was directed in the direction of the movement and blocking grooves (shooters) of a rod settled down outside.
4. Press a piston finger in the piston by hand.
5. Insert a lock ring into a flute.
6. Establish a tape for a staving of piston rings, and insert the piston into the cylinder shooters in the direction of the movement.
7. Establish conrod covers on rods on designations on them.
8. Turn a bent shaft and check ease of rotation.

Technical parameters

Piston gap
0.004-0.026 mm
Difference between the mass of the piston of each cylinder
8 g
Length of a piston finger
24.000 mm
Gap of landing of a piston finger in the piston
0.004-0.008 mm