1984 Corvette: Service Bulletin: Generator Noise (Moan) at Idle with Air Conditioning On

Subject:   Generator Noise (Moan) at Idle with Air Conditioning "On"
Model and Year: 1984 Corvette
Source: Chevrolet Dealer Service Bulletin
Bulletin Number: 84-151, Section 6D (VIy)
Date:   June 1984

TO:  ALL CHEVROLET DEALERS

Some 1984 Corvettes may exhibit the subject noise, which is commonly defined as a "moan".  This noise is induced into the generator by belt excitation when the air conditioning compressor is "on".

The following service procedure has been developed to reduce this noise by using three (3) new tubular braces and fasteners to replace the generator vibration period, which is the primary noise source.

Vehicles produced after VIN E5137968 have already utilized the new tubular braces.

The following components are required for this service procedure.

To insure proper installation, the following steps are to be performed:

1.  Remove the generator rear support brace.  Discard the support brace, attaching nut and attaching bolt.

2.  Remove and discard #1 and #3 L.H. exhaust manifold to cylinder head attaching bolts (see Figure 1).

3.  Install stud, P/N 14057002, in place of discarded #1 bolt and torque to 35 N.m.

4.  Install stud, P/N 3932448, and washer, P/N 2436163, in place of discarded #3 bolt and torque to 35 N.m.

NOTICE:  Washer is to be installed on stud between stud hex and exhaust manifold.

5.  Remove the serpentine belt from the generator pulley.

6.  Loosen generator attaching bolts (2).  (See Figure 1).

7.  Install three (3) tubular braces on the exhaust manifold studs as shown on Figure 2 and loosely retain with attaching nuts in three (3) places.

8.  Install bolt, P/N 14066303, in longer single brace and bolt, P/N 14063755, in two (2) short braces.  Loosely install bolts into generator housing (see Figure 2).

9.  Mandatory torque sequence (Figures1 and 2):

• Generator lower attaching bolt 50 N.m.
• Generator upper attaching bolt 50 N.m.
• Long tubular support brace to generator, attaching bolt 35 N.m.
• Two (2) short tubular support braces to generator, attaching bolt 50 N.m.
• Three (2) tubular support braces to three (3) exhaust manifold studs, 25 N.m. three (3) attaching nuts.

NOTICE:

The B+ wire on the generator should not contact the support brace(s).  If necessary, disconnect the battery and loosen the B+ cable eyelet, on the generator, and rotate the B+ wire to clear the support brace(s).  Re-torque the eyelet attaching nut and install the battery cable.

10.  Re-install serpentine belt.