LeSabre V6-231 3.8L VIN L SFI (1992)
Housing Assembly HVAC: All Technical Service Bulletins
A/C - Whistle/Flutter/Noise When Coming Off Full Heat
Bulletin: 92-1-18
Date: Oct. '92
Ref.No.: 92-294-1
Corp.Ref.No.: 201105
SUBJECT:
WHISTLE/FLUTTER/VIBRATION NOISE WHEN COMING OFF FULL HEAT POSITION (PROCEDURE TO MODIFY TEMPERATURE
DOOR)
MODELS AFFECTED:
1991-92 PARK AVENUE/ULTRA AND 1992 LESABRES WITHOUT DUAL ZONE AIR CONDITIONING
CONDITION:
On some 1991-92 Park Avenue/Ultra and 1992 LeSabre models (without dual zone A/C), a whistle/flutter/vibration noise may occur as the temperature
valve moves off maximum heat position. It may also sound like an intermittent noisy blower motor. The sound will cease once the temperature valve
which may be unevenly unseating from full heat position travels towards cold position.
TO VERIFY THE CONDITION:
On automatic A/C systems, drive the system to maximum heat position. When max heat position is reached, slowly decrease the temperature setting. If
the noise occurs and then ceases as the temperature valve moves from max heat, the vehicle has this condition.
On manual systems, drive the temperature valve to maximum heat position and on high blower. Slowly move the temperature setting to cold. If the noise
occurs and then ceases as the valve is moved toward cold, the vehicle has this condition.
CAUSE:
There are two items which may cause this to happen:
1.
The rubber seal between the two valve halves of the temperature valve may not be rigid enough allowing the top part of the valve to come off the
full heat position before the bottom causing flutter/vibration noise.
2.
The temperature valve shaft may not be tightly secured allowing the valve to tilt on its axis creating a gap and whistle/flutter/ vibration noise.
CORRECTION:
CAUTION:
THIS VEHICLE IS EQUIPPED WITH SUPPLEMENTAL INFLATABLE RESTRAINT (SIR). REFER TO THE SUPPLEMENTAL INFLATABLE
RESTRAINT (SIR) SECTION FOR CAUTIONS UNDER "ON-VEHICLE SERVICE" AND SIR COMPONENT AND WIRING LOCATION VIEWS
BEFORE PERFORMING SERVICE ON OR AROUND SIR COMPONENTS OR WIRING. FAILURE TO FOLLOW CAUTIONS COULD RESULT
IN POSSIBLE AIR BAG DEPLOYMENT, PERSONAL INJURY, OR OTHERWISE UNNEEDED SIR SYSTEM REPAIRS.
CAUTION:
BEFORE REMOVING OR INSTALLING ANY ELECTRICAL COMPONENTS, DISCONNECT THE NEGATIVE BATTERY CABLE TO HELP
PREVENT PERSONAL INJURY AND/OR DAMAGE TO THE VEHICLE OR ITS COMPONENTS.
1.
Using Tool J 37097, clamp off heater hoses and remove hoses from heater core.
