Cabin Air Filter ??

[Steve Z]

I have an 04 ZO6. Have problem with musty smell coming out of air vents. I did Speedratchets check of the air box and found no mice nest (clean as a whistle).Went to Auto Zone today to see if they had any spray to use in the intake to get rid of the smell. They said I have a cabin air filter that I had to get from the dealer. Do I

[teesz06]

No you don't

[IT L GO]

A musty or mildew odor when the fan is first turned on, or all the time when the system is running, can indicate that mold or mildew is growing in the evaporator box.

You can reduce the buildup of mold and mildew by turning the A/C recirculation switch off when you park the vehicle. If your vehicle doesn't have a recirculation switch, turn the A/C switch away from the "Max Air" position every time you shut the engine off.

DIY Tip

With the engine running, spray NOK-OUT or similar product available at the Auto Parts or Lysol into the ventilation system (at the base of the windshield). Turn the air circulation on high with all windows closed, run for a full 5 minutes. Open windows, continue running the fan for 5 minutes.

[Steve Z]

Thanks I'll try that. It only happens when I first start the car.

[BuilderBob]

Sounds like you may have water sitting in the condensation drain pan, which would indicate a clogged drain. Does the AC seem to be draining properly?

[panzer]

Try spraying some odor eliminator chemical into the vent air intake on the drivers side in front of the wiper to reduce the unpleasant smell.

[Zack]

Builder Bob: how would I unplug the "condensation drain pan" because I have this identical problem. Please be specific as possible as I am mechanically challenged. Thanks.

[Lawdogg]

I believe there is a service bulletin on this. GM will install something which will run the blower after the car is shut off to dry the ac. Saw it on an '02 Z06 that had complained to the dealer about smell.

[IT L GO]

99-01-39-004A
A/C - Odor Emission in Hot Weather
May, 2001


Subject: Air Conditioning Odor (Install Kit)

Models: 1993-2002 Passenger Cars, 1993-2002 Light & Medium Duty Trucks


This bulletin is being revised to update the model years, service procedure, parts information and to add the GEO and Medium Duty models. Please discard Corporate Bulletin Number 99-01-39-004 (Section 01 - HVAC).


Condition

Some customers may comment on odors emitted from the air conditioning system, primarily at start-up in hot humid climates.


Cause

This odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant, musty odor into the passenger compartment. There are several other possible sources of a musty odor in a vehicle. A common source is a water leak. Follow the Service Manual procedure for identifying and correcting water leaks if other odor sources are found. The procedure contained in this bulletin is only applicable if the source of the odor has already been determined to be the HVAC module.


Correction

To remove odors of this type, it is necessary to eliminate the microbial growth and prevent its re-occurrence. To accomplish this, the following steps must be completed:

# Apply evaporator core Cooling Coil Coating (Aerosol 6 oz), P/N 12377951 (AC Del co(R) 15-102) (in Canada, use P/N 10953503) or Cooling Coil Coating Kit with Extension Nozzle, P/N 12346391 (AC Del co(R) 10-120). Refills are available for the Cooling Coil Coating Kit with Extension Nozzle, P/N 12346391 (AC Del co(R) 10-120). Refer to the chart below.
# Install the Electronic Evaporator Dryer, P/N 12497910 (AC Del co(R) 15-5876).

Important: The Cooling Coil Coatings listed above are the only GM approved products for the disinfection and long-term control of evaporator microbial growth. The Cooling Coil Coating will disinfect the evaporator core and help inhibit the growth of future mold and mildew.

The Electronic Evaporator Dryer will activate when the ambient temperature near the module is above 16°C (60°F) when the vehicle is started up. Approximately 30 minutes after the vehicle has been turned off, the blower will activate for 10 seconds every 10 minutes for 2 hours unless the vehicle is restarted. If a restart occurs, the Electronic Evaporator Dryer module will reset automatically. This on/off blower activation will dry the evaporator core and case reducing the chance of reoccurring A/C odor. The Electronic Evaporator Dryer is self fused and has a battery rundown protection feature that inactivates the dryer if voltage drops below 12.5 volts.


Service Procedure

# Visually inspect the air conditioning evaporator drain hose for obstructions and/or working condition.
# The cooling coil coating fluid must be applied to a dry evaporator core. Apply coil coating fluid as described in the instructions supplied with the kit. In some instances, the blower motor resistor can be removed for this spraying operation. If used, the opening can be taped over and the nozzle inserted through a hole in the tape. The kit instructions identify a drilling procedure to apply the coating fluid. When using this type of procedure, care must be taken to avoid evaporator damage and any holes must be properly sealed. Some coating fluid may overflow from the drain hose.

Important: When installing the Electric Evaporator Module, you MUST use the included electrical splice connectors to ensure a splice.
# Complete detailed installation instructions and wire connectors are supplied with the Electronic Evaporator Dryer. The ground wire should be attached to a body ground source. If any other wire splicing procedures are needed, follow the wire repair procedures in the Electrical sub-section of Body & Accessories in the appropriate Service Manual. I f required, the evaporator dryer can be installed under hood away from extreme heat conditions (i.e. exhaust manifolds) and/or water splash areas. In all cases, the evaporator dryer module must be secured with a Velcro(R) strip (not included in the kit), or you may use the integral hooks to utilize tie straps. Using a Velcro(R) strip is preferred as the use of the integral hooks may cause rattles.
# When the installation procedure is complete and power is supplied, the module will self-test. Thirty seconds after power is supplied, the high blower speed will be activated 3 times (for 2 seconds per cycle). When the test has run, install the Electronic Evaporator Dryer label on the blower motor case in a visible area.


Parts Information

Parts are currently available from GMSPO.
Part Number Description
12377951
(AC Del co 15-102) Cooling Coil Coating
(Aerosol 6 oz)
12346391
(AC Del co 15-120) Cooling Coil Coating Kit w/Extension Nozzle
12346390
(AC Del co 15-121) Refill for Cooling Coil Coating Kit
12497910
(AC Del co 15-5876) Electronic Evaporator Dryer Module Kit


Warranty Information

Labor Operation Description Labor Time
D3316 Apply Cooling Coil Coating/Install Electronic Evaporator Dryer 0.8 hr
For vehicles repaired under warranty, use the table as shown.

[BuilderBob]

Originally Posted by Zack

Builder Bob: how would I unplug the "condensation drain pan" because I have this identical problem. Please be specific as possible as I am mechanically challenged. Thanks.

Not having done this to my Z, I don't know the location of the condensation drain tube. Maybe someone else can chime in on that. Once you find it, you just run a stiff wire up it or blow some compressed air into it to open it up. However, now that I've read IT L GO's post, your problem might just be as his post describes.

[Zrod]

IT L GO

[jrh009]

Originally Posted by BuilderBob

Not having done this to my Z, I don't know the location of the condensation drain tube. Maybe someone else can chime in on that. Once you find it, you just run a stiff wire up it or blow some compressed air into it to open it up. However, now that I've read IT L GO's post, your problem might just be as his post describes.

My bet is the drain is not plugged. I had the same problem and the drain was fine. Turn off the air and run a max heat for a couple of minutes just before shutting down.

I did this for a while and the problem disappeared. It comes back a little when I forget but not nearly as bad as it once was.

Haven't tried the recirc switch but it sounds like another good approach.

[ZO6 AL-X]

Let us know how you got rid of the smell.