M/T - Clutch Won't Disengage In Cold Weather

# 04-07-31-007: Clutch Intermittently Does Not Disengage During Cold Weather (Replace Clutch Master Cylinder) - (Jul 1, 2011)

Subject: Clutch Intermittently Does Not Disengage During Cold Weather (Replace Clutch Master Cylinder)

Models:
2004 Chevrolet Optra
2004-2005 Chevrolet Aveo
2005 Pontiac Wave (Canada Only)





Built Prior to the Following VIN Breakpoints:

Condition
Some customers may comment that the clutch does not disengage during cold weather. This condition occurs intermittently.

Cause
When the clutch pedal returns, negative pressure is formed inside the clutch master cylinder. During cold weather, the viscosity of the fluid changes. In this condition, ambient air can intrude into the clutch master cylinder between the piston cup and the cylinder case due to the negative pressure. The air in the cylinder will interrupt the fluid return, resulting in intermittent disengagement of the clutch.

Correction
Replace the clutch master cylinder. Refer to Clutch Master Cylinder Replacement in SI.





Parts Information
Parts are expected to be available from GMSPO on November 15, 2004.





Warranty Information
For vehicles repaired under warranty, use the above chart.




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