A/C - Poor Heating Performance in Extreme Cold Weather
Bulletin No.: 04-01-37-003ADate: June 14, 2004
TECHNICAL
Subject:
Poor Heating Performance/Insufficient Heat During Low Ambient Temperatures (Check Coolant Concentration, Drain Specified Amount of Coolant and Refill with Water)
Models:
2004 Chevrolet Aveo Built Prior to VIN Breakpoint 4B181709
2004 Chevrolet Optra Built Prior to VIN Breakpoint 4K978270
Attention:
This bulletin is intended for vehicles sold only in Canada
Supercede:
This bulletin is being revised to add VIN breakpoints information and remove the Epica model. Please discard Corporate Bulletin Number 04-01-37-003 (Section 01 - HVAC).
Condition
Some customers may comment on less than desirable heater performance, especially when ambient temperature is below -20°C (-4°F).
Cause
The cause of this condition may be a higher than required engine coolant concentration. In cold ambient temperatures, this higher concentration may result in the coolant being in a jelly-like state, which can restrict the coolant flow through the heater core.
Correction
1. Check the engine coolant concentration using J-23688 (Fahrenheit scale) or J-26568 (Celsius scale) or equivalent coolant Refractometer. DO NOT use a coolant hydrometer, as inaccurate readings may occur.
2. If the coolant concentration (percent antifreeze/water mixture) indicated is above 60 percent (-50°C (-58°F)), drain the appropriate amount of coolant from the radiator (see chart). Refer to Draining and Filling Cooling System in the Engine Cooling sub-section of the Service Manual.
3. After draining the coolant, refill the same drained volume with clean drinkable water.
4. Start the engine.
5. Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
6. Allow the engine to idle for 3 minutes.
7. Shut the engine OFF.
8. Allow the engine to cool.
9. Recheck and see if the coolant concentration is in the range of 55 percent to 60 percent (-43°C to -50°C (-45°F to -58°F)).
10. If necessary, repeat steps 2-9 to achieve engine coolant concentration range of 55 percent to 60 percent (-43°C to -50°C (-45°F to -58°F)).
Warranty Information
For vehicles repaired under warranty, use the table.
Disclaimer