Noisy A/C System .
A gurgling noise is heard inside the passenger compartment. The noise is coming from the A/C heater case.
A gurgling noise in the heater core may be caused by a low coolant level in the cooling system or a restricted a heater core .
Low coolant level
A low coolant level will allow too much air in the cooling system.
The excessive air in the system will mix with the coolant and create the gurgling noise.
Heater core restricted.
A restricted heater core will also cause a gurgling noise from the coolant passing through the restricted area.