7B
Whistling sound is heard from A/C evaporator
There are various types of noise, ranging from those produced in the engine compartment to those from the passenger compartment, also from rumbling noises to whistling noises.
Abnormal Noise from A/C Evaporator
Condition Possible Cause Action
Whistling sound is heard from A/C evaporator
Depending on the combination of the interior/exterior temperatures, engine rpm and refrigerant pressure, the refrigerant flowing out of the expansion valve may, under certain conditions, make a whistling sound
At times, slightly decreasing refrigerant volume may stop this noise. Inspect expansion valve and replace if faulty.