Engine belt

Description

The Poly-V-belt drive (commonly known as the Serpentine Belt) drives engine components (alternator, AC compressor, etc.) from the engine.

Layout Diagrams

Crankshaft turns clockwise.

S350/S430/S500

Automatic belt tensioner
ABC tandem pump (pump for power-steering assistance and ABC chassis)
Air conditioning compressor
Crankshaft
Coolant pump
Generator (alternator)
Idler pulley

Length: 2380mm

6-groove single-belt drive, with AC compressor

1 - Crankshaft
2 - AC compressor
3 - Power steering pump
4 - Guide pulley 1
5 - Generator
6 - Coolant pump and fan
7 - Tension pulley

Part no:

A0119979792
Bosch 1987946046 (length 2390mm)
Continental ctam 6PK2390 (length 2390mm)

S55 AMG

The S 55 AMG has two poly-V-belts (belt one shown in purple/belt two shown in black).

Idler pulley
Automatic belt tensioner
ABC tandem pump (pump for power-steering assistance and ABC chassis)
Air conditioning compressor
Crankshaft
Coolant pump
Generator (alternator)
Idler pulley
Automatic belt tensioner
Supercharger

Length of belt one: 1289 mm

Length of belt two: 2462 mm

S600

Automatic belt tensioner
ABC tandem pump (pump for power-steering assistance and ABC chassis)
Air conditioning compressor
Crankshaft
Coolant pump
Generator (alternator)
Idler pulley
Idler pulley
Idler pulley

Length: 2335 mm

Replacing belt

To remove tension from idler pulley, locate 17mm tensioner bolt located on tensioner bracket (see photo below). Belt obstructs the view so it has to be found by feel. After locating 17mm bolt, push down the bar counter-clockwise (see photo below). When putting the belt back on, it is easier to leave the last part of the belt to slide over the water pump pulley as it has no lip or grooves.