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
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Length: 2380mm |
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6-groove single-belt drive, with AC compressor
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Part no:
- A0119979792
- Bosch 1987946046 (length 2390mm)
- Continental ctam 6PK2390 (length 2390mm)
S55 AMG
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The S 55 AMG has two poly-V-belts (belt one shown in purple/belt two shown in black).
Length of belt one: 1289 mm Length of belt two: 2462 mm |
S600
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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.
Belt tightener
Tensioner pulley
MB does not have a separate part number for belt tensioner pulley - only for the entire assembly. However, several aftermarket manufacturers sell tensioner pulley separately.
Part numbers:
- OE A1122000970 (250 EUR)
- Gates T38174 (100 EUR)
- FEBEST 1687-W163 (6 EUR) - only pulley
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To remove pulley, unscrew bolt using Security Torx T50 bit.
To remove tensioner assembly, unscrew two Torx E12 bolts. The tensioner has to be fixed in tensioned position to get access to the second bolt.
Idler pulley
Also known as "guide pulley" or "sheave pulley".
Part numbers:
- OE A0002020919 (30 EUR)
- SWAG 30030032 / Febi bilstein 11276 (5 EUR)
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