Heater - Poor Performance

Group Ref.: 1 - HVAC
Bulletin No. 431102
Date: June, 1994

SUBJECT:
POOR HEATER PERFORMANCE (RESEAL HEATER CORE TO HEATER CASE SEAL)

MODELS:
1993-94 CHEVROLET CAMARO
1993-94 PONTIAC FIREBIRD

CONDITIONS:
Customers may comment on poor heater performance.

CAUSE:





The heater core to heater case seal may become loose, allowing cool air to blow by the heater core instead of passing through it. See Figure 1.

CORRECTION:
The heater core to heater case seal may be re-attached by the following procedure:

1. Remove RH side sound insulator assembly.

2. Remove Instrument panel compartment door (glove box).

3. Unsnap evaporator temperature module and pull heater core cover out and down.

4. Verify that seal has pulled away from heater case by visually inspecting. See Figure 1.

5. Remove heater core clamp.





6. Glue down seal and install an aluminum or plastic seal retention strip approximately 6-1/2" X 3/4" (165 mm X 19 mm) to hold seal in place. Thickness of strip can range from 1/16" to 3/16" (1.6 mm - 4.7 mm). See Figure 2.

To glue seal in place, use GM Weatherstrip adhesive P/N 12345096 or 3M adhesive (3M P/N 080-11) or equivalent.

7. Hold seal retention strip in place and reinstall heater core clamp.

NOTE:
It is important that a steel strip not be used as it may cause corrosion problems.

8. Install heater core cover.





NOTE:
On some 1993 models, It may be necessary to modify the cover to ease cover Installation. If necessary to modity, trim heater core cover upper right side corner top flange approximately 0.6" (15 mm). Heater core cover has a tongue and groove seal and must be engaged to seal properly. See Figure 3.

9. Install RH side sound insulator assembly.

10. Install Instrument panel compartment door (glove box).

WARRANTY INFORMATION:
For vehicles repaired under warranty, use:

Labor Operation: D2812

Labor Time: 0.3 Hr.