mold/smell coming from vents?!

[warrior86]

hey guys, i have a 94 4.3 HO 4wd tahoe edition with 350k miles. It used to be my uncles truck but now it is mine. For the past two years i have noticed a smell that seems to come from the defroster vents on top of the dash. Some of my friends say it smells like mold, but i wouldnt know. Makes sense tho because i did get strep throat times in 3 months when i was driving the truck daily.

The smell happens when i start moving. I dont really notice it when the truck is warming up. It happens whether or not i have the heat/def on or off. As soon as i start driving, i get this smell. My question is how do i clean out the air ducts or whatever teh air passes through and eventually gets to my vents. I took the front cowl off (where the windshield wiper arms move) and i couldnt find anything that seemed like the air would go through. Any suggestions would really be appreciated. Thanks

[Joker2040]

There is some junk that you can spray into the vents so that it re-circulates in the system and cleans it out. I can't remember the name of it though.

[Joker2040]

ozium... that's it

[Sparky2263]

Unless it's the heater core starting to leak. Does it have an anti-freeze type smell?

[warrior86]

no, not an antifreeze smell. Its been there for atleast two years. I had the car for a year gave it back to my uncle and now i have it again. The smell is similar to how sweaty clothes smell if you dont get them in the laundry right away.

I dont think it can be anything in the car because you dont notice it until you start moving and/or turn the heat on or something. Its a pretty strong smell too. I find myself having to drive with the windows open just to get some ventilation.

[Sparky2263]

GM makes a foam cleaner. You remove the blower resistor from the evap. box under the hood. Spray it in, let it sit, wash it out. Gets the mold off the evaporator.

[Tink]

Also, to keep it from happening, when you run the AC, right before you shut off the vehicle, turn off the AC and turn the vent on high for a minute... when you shut off the vehicle with the AC on the temperature difference between the AC and the outside air temperatures causes water to condensate in your AC system, vents and evaportor... in which, bacteria, fungus, mold, and spores can all grow.

[warrior86]

ok, thanks for all the responses. Would u happen to know the name of the foam cleaner? or will chevy know what im talking about? Just call it evaporator box cleaner? Thanks, ill let u know how everything works out.

[Sparky2263]

Got in a hurry leaving the shop. Wrote the PN down on my desk. Will post tomm.

[Sparky2263]

File In Section: 01 - HVAC
Bulletin No.: 99-01-39-004A
Date: May, 2001
TECHNICAL
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 reoccurrence. To accomplish this, the following steps must be completed:

1.Apply evaporator core Cooling Coil Coating
(Aerosol 6 oz), P/N 12377951 (AC Delco(R) 15-102)
(in Canada, use P/N 10953503) or Cooling Coil
Coating Kit with Extension Nozzle, P/N 12346391
(AC Delco(R) 10-120).

Refills are available for the Cooling Coil Coating
Kit with Extension Nozzle, P/N 12346391
(AC Delco(R) 10-120). Refer to the chart below.

2.Install the Electronic Evaporator Dryer, P/N 12497910 (AC Delco(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

1.Visually inspect the air conditioning evaporator drain hose for obstructions and/or working condition.

2.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.



3.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. If required, the evaporator dryer can be installed underhood 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.

4.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.



http://motoralldata.com/alldata/MOTOR~V26952424~C36229~R0~OB0~P3R0H~N/0/86372027/87576902/87576915/87576917/34853741/34865608/34850853/42063576/57170451/86536638/87570790/87570791

[Sparky2263]

The afterblow kit does what Tink suggested. Works damn good.

(Thread moved to the appropriate section)

[Sparky2263]

The newest part number they have for the mold killer is 12378554.

[warrior86]

thank you...your response is greatly appreciated!

[warrior86]

alright guys heres the update. My friend works at a nissan service center. They have this stuff called "frigi-fresh". Its supposed to get rid of smells and spores in the ac system. Figured it the nissan version of the GM stuff, only its free for me. We sprayed two cans in the evaporator box and it seemed to fix the smell for about a week...or atleast cover it up. One of the two. Now its back.

before i go and try that gm stuff, i was also thinking (and feel free to tell me this is stupid) of spraying Tinactin antifungal spray or Lysol antibacterial spray in there. Waddaya guys think? Or should i just go with the GM stuff? thanks