For 1990-2009 cars

Checks | Causes
--- | ---
In certain high-humidity operating conditions, a musty odor may develop. The odor develops because of a microbial growth in the evaporator area. Usually, this odor is temporary. If the climate changes, the condition will disappear. If the mold odor or the mildew odor remains, refer Odor Correction to.
A musty odor. |

• | Mold or mildew is present in the evaporator fins. Clean the evaporator fins. Refer to Odor Correction or to Evaporator Core Replacement .

• | An obstruction exists in the evaporator drain. Clean the evaporator drain.

• | Interior water leaks exist in the body. Seal the body.

A coolant odor. | A coolant leak exists. Inspect the heater hoses and the core for leakage. Refer to Heater Hoses Replacement or to Heater Core Replacement .
A refrigerant oil odor. | A refrigerant leak exists at the evaporator. Inspect the evaporator and the fittings for refrigerant leakage. Refer to Leak Testing .