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Air Cleaner Element - Dust Intrusion

GROUP REF.: Engine Fuel & Emission

BULLETIN NO.: 476507

DATE: March, 1994

SUBJECT:
DUST INTRUSION PAST AIR FILTER DURING OFF-ROAD USE (INSTALL DUAL STUD AIR CLEANER COVER)

MODELS:
1986-93 CHEVROLET AND GMC TRUCK S/T TRUCKS AND M/L VANS
1991-92 OLDSMOBILE BRAVADA
1992 CHEVROLET AND GMC TRUCK C/K AND P TRUCKS AND G VANS
WITH 4.3L TBI ENGINES (RPO LB4 - VIN Z)


THIS BULLETIN CANCELS AND SUPERSEDES CORPORATE BULLETIN 036001R.
PREVIOUS DIVISIONAL PUBLICATION NUMBERS WERE:

DIVISION BULLETIN NUMBER

CHEVROLET 91-21-6
GMC TRUCK 91-6-06
GM OF CANADA 90-643-102

CONDITION:
Some owners operating their vehicle off road or in extremely dusty conditions may experience dust intrusion past the air cleaner element.

CORRECTION:
The dust intrusion may be reduced or eliminated by installing a dual stud air cleaner cover.

SERVICE PROCEDURE:



The following steps should be used to install a dual stud air cleaner lid (see Figure 1):

1. Remove air cleaner.

2. Remove and discard old air cleaner stud.

3. Remove adapter ring from throttle body.

4. Remove and discard two rear throttle body attaching bolts.

5. Install two new TBI hold down bolts. Torque the bolts to 16 Nm (12 lbs.ft.).

6. Install adapter ring on throttle body.

7. Install two new air cleaner studs into top of TBI hold down bolts. Torque studs to 5 Nm (4 lbs.ft.).

8. Install lower air cleaner body.

9. Reinstall air filter element.

10. Install new air cleaner lid using two new wing nuts.

SERVICE PARTS INFORMATION:
For S/T and C/K trucks, use the following parts list:

Part Number Description Quantity

10105373 Bolt, TBI Hold Down (rear) 2
10118792 Nut, Wing 2
25098971 Lid Assembly 1
10187639 Stud, Air Cleaner-143 mm 2

For M/L and G/P trucks, use the following parts list:

Part Number Description Quantity

10105373 Bolt, TBI Hold Down (rear) 2
10118792 Nut, Wing 2
25098971 Lid Assembly 1
10187640 Stud, Air Cleaner-170 mm 2

Parts are currently available from GMSPO.

WARRANTY INFORMATION:
For vehicles repaired under warranty, use:

Labor Operation Vehicle Labor Time (Hours)

T1604 S/T 0.2
M/L 0.4
C/K 0.2
G 0.5
P 0.4