GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

DEFINITION: Under certain climate and operating conditions, a musty odor develops from mold growth in the evaporator core face. This odor is generally temporary and as climate conditions change the odor will disappear and repair itself. If the odor persists, it will be necessary to clean the face of the evaporator core with the appropriate cleaner. Leaking anti-freeze or refrigerant oil can also cause problem odors in the air conditioning system..

1

Is the evaporator drain clean?

--

Go to Step 3

Go to Step 2

2

Clean the evaporator drain.

Is the drain clean?

--

System OK

--

3

Inspect the evaporator for mold or mildew.

Is the evaporator clean?

--

Go to Step 5

Go to Step 4

4

Clean the evaporator.

Is the evaporator clean?

--

System OK

--

5

Inspect the vehicle body for water leaks.

Are water leaks present?

--

Go to Step 6

System OK

6

Seal the body.

Is the body sealed?

--

System OK

--

7

Inspect for anti-freeze around the heater core.

Is there an anti-freeze leak around the heater core?

--

Go to Step 8

Go to Step 9

8

Replace the heater core.

Is the repair complete?

--

System OK

--

9

Check for anti-freeze around the heater hoses.

Is there an anti-freeze leak from the heater hoses?

--

Go to Step 10

System OK

10

Replace the heater hose.

Is the repair complete?

--

System OK

--

11

Check for a refrigerant leak at the evaporator core.

Is there refrigerant oil on the evaporator core?

--

Go to Step 12

System OK

12

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

Is the repair complete?

--

System OK

--