Engine - Vibration/Boom

Bulletin No. T 83-77
File In Group 6A
Number 38
Date April '83

HT4100 ENGINE VIBRATION/BOOM - 1982 C-CAR

FIGURE 1 - Rear Generator Brace Assembly:

Some 1982 C-cars equipped with HT4100 engines may exhibit a vibration and/or boom in the 900-1100 RPM, 1600-1700 RPM, and/or 1900-2200 RPM ranges. This condition is due to the vibration of the rear generator to exhaust manifold brace (refer to Figure 1).

A revised brace (P/N 1627687) has been released to correct this condition and went into production at the beginning of the 1983 model year. The material thickness of the revised brace has been increased to 2 mm as compared to the previous brace material thickness of 1 mm.

The revised brace is available through GMWDD and should be installed to correct 1982 C-cars exhibiting this condition.

For warranty purposes, use Operation Number J4140 at .2 hour.