DeVille V8-252 4.1L VIN 8 FI (1983)
Drive Belt: All Technical Service Bulletins
Serpentine Accessory Belt - Noisey/Premature Wear
Bulletin No. T
87-60
File in Group
6B
Number
15
Corp. Ref. No.
716203
Date
Jan. '87
SUBJECT:
SERPENTINE ENGINE ACCESSORY BELT CONDITIONS
MODELS AFFECTED: ALL WITH TRANSVERSELY MOUNTED HT4100 ENGINES
Figure 1 - Generator/Idler Pulley Bracket
The serpentine engine accessory drive belt used on transversely mounted HT4100 engines may experience premature belt wear and/or unusual belt noise
conditions.
Belt Wear
Premature drive belt wear is usually caused by pulley misalignment. Serviceman Bulletin T-85-58 discusses this condition with emphasis on establishing
correct idler pulley alignment. Beginning with the following 1986 vehicles (C-332942, E-612388, K-810146) design of the idler pulley and bracket
changed to the cast aluminum design shown in Figure 1. Shimming of the pulley bracket as described in Bulletin T-85-58 should not be required with the
cast bracket. Retrofit using the cast aluminum generator/idler pulley bracket can be accomplished by ordering the parts shown in Figure 1 if desired,
however, this modification provides no advantages over a properly aligned stamped steel idler pulley bracket. This modification is not possible on 1985
vehicles before 321327 equipped with a 108 amp generator. The cast bracket is designed for the 120 amp generator only. Refer to Serviceman Bulletin
T-85-106 for details of generator changes.
Belt Noise
Serpentine belt noise is most noticeable at idle. Various other drive system components (tensioner, A/C compressor, generator) may appear to be the
cause of the noise which is the result of the belt. A new design drive belt was recently released for service use only under P/N 1643049 to replace
1625690 for all 1986 and 1987 C, E, K, and V cars and 1985 "C" cars after 321327 (120 amp generator). The belt can be easily identified by a six inch
orange band on the outside diameter. This belt is not used in production.
