Evaporator Core: Testing and Inspection

A faulty evaporator will provide insufficient cooling to the vehicle. The core may be restricted with dirt, the case may be cracked, or a seal may be leaking sufficiently to prevent cooling. If evaporator restriction is due to icing, the expansion valve, capillary tube or suction throttling valve, if equipped, may be at fault and should be investigated.
Since there is a constant condensation of atmospheric moisture on the outside of the evaporator coils, ensure that the draining system is unobstructed and clean. Some vehicles have an auxiliary evaporator in the trunk or between the headliner and the roof.