Grand AM V6-3300 33L (1992) - Slow Warm Up/Inadequate Performance at Idle
Thermostat: All Technical Service Bulletins
Heater - Slow Warm Up/Inadequate Performance at Idle
FILE IN SECTION: 1 - HVAC
BULLETIN NO.: 43-11-12
DATE: May, 1995
SUBJECT:
Slow Heater Warm-Up or Inadequate Heater Performance During Engine Idle (Replace Floor Air Outlet and Flush Heater Core)
MODELS:
1992-93 Buick Skylark
1992-93 Oldsmobile Achieva
1992-93 Pontiac Grand Am
with 2.3L Engine (VIN D - RPO LD2, VIN 3 - RPO L4O), 3.3L Engine (VIN N - RPO LG7)
This bulletin cancels and supersedes Corporate Bulletin Number 331102
(Group Reference I - HVAC).
CONDITION
Some owners may comment on a condition where the heater air is slow to warm up or the heater outlet air during idle is not warm enough.
CAUSE
Some vehicles may exhibit a condition where the air flow from the floor air outlet does not provide enough circulation to the front of the passenger
compartment. A new floor air outlet has been designed to redirect air flow to the front seat and to distribute air more evenly across the floor.
Also, some engine core sand may have accumulated in the heater core, resulting in reduced coolant flow. A backflush of the heater core ONLY will
remove this debris.
To further assist vehicles equipped with VIN D and 3 engines, a new 205°F (96°C) thermostat has been developed. For vehicles equipped with VIN D
and 3 engines, Federal Emissions ONLY, a new EPROM has been calibrated to increase cold weather idle boost. This elevated idle increases water
temperature and flow through the heater core, thus improving performance.
CORRECTION
Vehicles equipped with VIN D and 3 engines with Federal Emissions:
1. Replace thermostat.
2. Replace floor air outlet.
3. Replace EPROM.
4. Flush heater core.
Vehicles equipped with VIN D and 3 engines with California Emissions:
1. Replace floor air outlet.
2. Flush heater core.
Vehicles equipped with VIN N engine, either California or Federal Emissions:
1. Replace floor air outlet.
2. Flush heater core.
SERVICE PROCEDURE
Heater core flush -
1. Disconnect heater hoses from heater core.