GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC Suburban - 4WD 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Odor Diagnosis
Table 1: Musty Smell
Table 2: Refrigerant Leak

Musty Smell

Problem

Action

Water leaks from the body.

Seal the body.

The evaporator drain is clogged.

Clean the drain.

Mold or mildew is present.

Clean the evaporator.

Coolant Smell

Problem

Action

The anti-freeze leaks.
  1. Inspect the heater core.
  2. Inspect the pipes.
  3. Inspect the hoses.
  4. Repair or replace the components as necessary.

Refrigerant Leak

Problem

Action

The refrigerant oil leaks.

Inspect the evaporator core. Repair or replace the evaporator core as necessary. Refer to Air Conditioning Evaporator Core Replacement .

Mold/Mildew Odor Problem

Under certain climate and operating conditions, a musty odor develops from mold growth in the evaporator core face. This odor is generally temporary. As climate conditions change the odor will disappear and repair automatically. If the odor persists, remove the evaporator core. Clean the evaporator core face with the appropriate cleaner.