GM Service Manual Online
For 1990-2009 cars only
Table 1: Musty Smell
Table 2: Coolant Smell
Table 3: Refrigerant Oil Smell

Musty Smell

Problem

Action

Important: In certain climates and operating conditions a musty odor may develop. The odor is caused by a microbial growth in the evaporator core. This odor is generally temporary. As climate conditions change, the odor will disappear. If the odor persists it may become necessary to clean the evaporator core with an appropriate cleaner.

Water leaks (body) are present.

Locate and repair any water leaks. Refer to Body Waterleak Repair in Waterleaks.

The evaporator drain is blocked.

Clean the evaporator drain.

There is mold or mildew on the evaporator core.

Clean the evaporator. Refer to Odor Correction .

Coolant Smell

Problem

Action

The heater core is leaking.

Replace the heater core. Refer to Heater Core Replacement .

The heater core hoses are leaking.

Replace the heater hoses. Refer to Heater Hoses Replacement .

Refrigerant Oil Smell

Problem

Action

The evaporator core is leaking.

Replace the evaporator core. Refer to Air Conditioning Evaporator Core Replacement .