Corvette Air Conditioning - A/C Diagnostics: Keeping Your Cool, Part 2

James Berry Jun 1, 2011 0 Comment(s)
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Gauge Readings: low side—0 psi or vacuum (low)/high side—212 to 250 psi (normal)

Vemp 1106 07 Corvette Air 2/10

Symptoms: The air from the vents is slightly cool. Look for frost or sweat on the high-side hoses. Remember, sweat is normal on the low-side hoses, but not the high-side ones.

Conclusion: There is likely a restriction in the high side of the system. Frost or sweat will be most prominent just after the point of restriction. The hose or line may be cool to the touch near the restriction.

Repair Procedure: If a component or line is found to be defective, replace the defective component and the accumulator/dryer. Flushing the A/C system can help clean blockages by dislodging sludge and debris and purging it from the system. After flushing, put the system into a vacuum for approximately 20 minutes to boil out any moisture. Then recharge the system with the factory-specified amount of refrigerant. Any oil that was lost should be re-added during the recharge process. Check the A/C system's operation and performance.

Gauge Readings: low side—55 to 65 psi (high)/high side—100 to 120 psi (low)

Vemp 1106 08 Corvette Air 3/10

Symptoms: The air from the vents is warm. The compressor may be noisy when it operates.

Conclusion: An internal component of the compressor has likely failed. Also check to make sure the drive belt is tight and not worn. A slipping drive belt could cause a false reading.

Repair Procedure: Recover the remaining refrigerant from the system and replace the compressor. You should always replace the expansion valve and accumulator/dryer when a compressor fails.

Flushing the A/C system can help clean blockages by dislodging sludge and debris and purging it from the system. After flushing, put the system into a vacuum for approximately 20 minutes to boil out any moisture. Then recharge the system with the factory-specified amount of refrigerant. Any oil that was lost should be re-added during the recharge process. Check the A/C system's operation and performance.

Gauge Readings: low side—55 to 65 psi (high)/high side—310 to 350 psi (high)

Vemp 1106 09 Corvette Air 4/10

Symptoms: The air from the vents is warm. The high pressure hoses are very hot.

Conclusion: The condenser is likely malfunctioning. It's also possible that there is an overcharge of refrigerant inside the system.

Repair Procedure: The best way to ensure you have the correct charge in the system is to recover the remaining refrigerant. Put the system into a vacuum for approximately 20 minutes to boil out any moisture, then recharge it with the factory-specified amount of refrigerant. Any oil that was lost should be re-added during the recharge process. Check the A/C system's operation and performance.

If both gauges still read high, verify that the engine-cooling system is full and operating correctly. Also verify that the engine-cooling fans are functioning properly. Electric cooling fans should continually run when the engine is on and the air conditioning is engaged.

Inspect the coil of the condenser and radiator for debris on the external fins. If debris is found, clean and retest the A/C system.

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