Whistling sound is heard from evaporator

Abnormal Noise from Evaporator

Condition	Possible Cause	Action
Whistling sound is heard from evaporator	Depending on the combination of the interior / exterior temperatures, engine rpm and refrigerant pressure, the refrigerant flowing out of the expansion valve may generate whistling sound.	Slightly decreasing amount of refrigerant may stop this noise. Check expansion valve and replace it if faulty.