Valve Train Noise Due to Stretched Timing Chain

2. ENGINES 102.961/985 VALVE TRAIN NOISE DUE TO STRETCHED TIMING CHAIN

Several production changes were phased-in over a period of time, with the most recent being the change from a single roller timing chain to a double roller timing chain.

Effective Serial Number Range

Model Transmission Engine End Number Chassis End Number Month/Year

201.028 Automatic 067143 468003 January 1988

Manual 022013 468933 February 1988

Note:
In addition to the timing chain, many other parts have been modified. Therefore, conversion from a single roller timing chain to a double roller timing chain is not recommended on previously manufactured engines.

In case of a verified customer complaint regarding engine noise caused by a stretched single roller timing chain, install the notched single roller timing chain with barrel-shaped roller sleeves. At the same time, inspect the chain tensioner as described in the W.I. 222 Grp. 05.

If the chain tensioner is okay (thrust pin not seized) or after installation of a new timing chain (chain tensioner functional); and valve train noise during starting of the engine persists, install modified chain tensioner (part no. 102 050 19 11 05).





Other Production Change Phase-Ins

Date Production Change

December 1985 Chain tensioner with modified detent spring (Fig. 5)

August 1986 Tensioning rail with profiled lining (Fig. 3)

Oil spray nozzles
November 1986 Version 1 (1, Fig. 4)
July 1987 Version 2 (2, Fig. 4)

July 1987 Notched single roller timing chain with barrel-shaped roller sleeves


Parts Information

Part Name Part Number

Single roller timing chain 001 997 70 94

Chain tensioner with detent spring 102 050 10 11

Modified chain tensioner with detent spring 102 050 19 11 05