1985-88 ENGINE COOLING SYSTEMS Mercedes-Benz Serpentine Drive Belts
DESCRIPTION

The single ("serpentine" or "V" ribbed) drive belt system has been adopted by manufacturer's as a replacement for multiple "V" belt systems previously offered. The "serpentine" belt requires a suitable belt tensioner similar to those used to control timing belt tension.

Use of a tensioner allows engine accessories to be mounted rigidly on the engine. The single belt drive system has a predicted life of 100,000 miles before replacement is required.

The belt tensioner has a wide functional range and is capable of maintaining tension during the expected life of the belt. Tensioner cannot compensate for extreme belt lengths. Poor tension control and possible tensioner damage can result from excessive belt length.
IDENTIFICATION

ENGINE CODE APPLICATION
Application Engine Code
190, 190 E, 200, 200 T, 200 E, 200 TE, 230 E, 230 CE, 230 TE 102
190 E (2.6), 260 E, 260 SE 300 E, 300 CE, 300 TE 300 SE, 300 SEL 103
200 D, 200 TD 601
190 D, 190 D Turbo, 250 D, 250 D Turbo, 250 TD 602
300 D, 300 D Turbo, 300 SDL 300 TD Turbo 603
SERPENTINE BELT ROUTING

NOTE: Inspect belt for fraying. If fraying has occurred, ensure belt and tensioner are aligned properly. If tensioner has reached its limit of travel, belt is excessively stretched and replacement of belt is required. If excessive noise is noticed from tensioner or idler, check for possible bearing failure. Small cracks in the back of the belt are acceptable. Do not apply "Belt Dressing" or any other additive to serpentine belt.

NOTE: Install belt on crankshaft and belt-driven components as shown. Adjust tensioner.
ENGINE 102 BELT ROUTING

NOTE: When mounting belts, start at tensioner roller (1) and continue in sequence of numbers. Loosen tensioner fixing bolt, turn tensioner adjuster rod until scale marks are as specified. Tighten tensioner fixing bolt. Refer to appropriate Figures for specific engine.

ENGINE 102 SERPENTINE BELT ROUTING
Figure No. Belt Length In. (mm) Belt Tension Adjustment Needle/Scale Marks
1 40.157 (1020) 5
2 74.213 (1885) 8-9 (1)
3 77.953 (1980) 8-9 (1)
(1) 2nd version adjusting needle - Central, thick line behind triangle.

Fig. 1: Engine 102 Belt Routing (1 of 3)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA

Fig. 2: Engine 102 Belt Routing (2 of 3)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA

Fig. 3: Engine 102 Belt Routing (3 of 3)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA
ENGINE 103 BELT ROUTING

NOTE: When mounting belts, start at tensioner roller (1) and continue in sequence of numbers. Loosen tensioner fixing bolt, turn tensioner adjuster rod until scale marks are as specified. Tighten tensioner fixing bolt. Refer to appropriate Figures for specific engine.