Stinky Air Conditioner

[IonFizzle]

Hi, folks!

I own a 2004 Honda Accord EX Sedan and for the last 5000 to 7000 miles (the car has just over 20k total) the air has been extremely musty and...dirty smelling when I use the MAX A/C button, which of course turns on A.C. as well as in-cabin circulation.

I noticed a thread about the simple change of the cabin air filter. Will this fix the musty gross air my A/C is putting out?

Thanks for your time.

-Cameron

[Foreign_Wide]

Certainly would seem like a good place to start.

[Trip]

While the filter is out, you could also try spraying some unscented Lysol into the filter housing while the fan is running. In case there is mold or something in the system, the Lysol would help kill it. That with a new filter and you should be all set. If it persists, a trip to the dealer might be in order.

**Tip: Do you drive with the recirc engaged? After the A/C cools the interior, be sure to switch it off to let fresh air into the system. If you have an EX-L (with leather and AUTO climate control), you can manually override the recirc button by tapping it OFF. The other functions will still remain in AUTO mode.

[touch of grey]

Originally Posted by Trip

While the filter is out, you could also try spraying some unscented Lysol into the filter housing while the fan is running. In case there is mold or something in the system, the Lysol would help kill it. That with a new filter and you should be all set. If it persists, a trip to the dealer might be in order.

**Tip: Do you drive with the recirc engaged? After the A/C cools the interior, be sure to switch it off to let fresh air into the system. If you have an EX-L (with leather and AUTO climate control), you can manually override the recirc button by tapping it OFF. The other functions will still remain in AUTO mode.

Why switch off the recirc?? I keep it on so I don't have to smell exhaust from the cars in front of me.

[Accordlover]

Originally Posted by touch of grey

Why switch off the recirc?? I keep it on so I don't have to smell exhaust from the cars in front of me.

As do I. The only time it bothers me is if the A/C is not running, then I put it on fresh air.

[stevel]

here's one solution.

Condition

Unpleasant “musty” odor from Heating and Ventilation system. Odor mainly occurs after vehicle has been sitting (unused) at least 5 hours and within 20 to 60 seconds after vehicle is first started.

Technical Background

Condensate is a normal condition in all A/C systems. If odor is noticeable without engine started, this may be due to mold and mildew in the passenger compartment, not from the A/C system. All other possible sources of unpleasant odor must be addressed before performing this Technical Service Bulletin. Consider the following conditions before proceeding:

• Evaporator housing drain must be open and free of debris.
• Cabin must be sealed with no water ingress into the passenger compartment.
• Plenum drains must be clear and free of debris.
• Pollen filter must be clean and free of moisture.

Contaminants are effectively neutralized using the Aircomatic® II Ultrasonic Climate System Cleaner (VAS 6189A) and Airco-Clean® Ultrasonic Air Conditioning Treatment (VAS 6189/1). All other cleaning methods are no longer permitted.

Production solution

Not applicable.

Service

If the vehicle is equipped with a pollen filter that is located inside the cabin such as in the A3, A6 and Audi Q7 then the pollen filter element will need to be removed and its cover reinstalled before performing this procedure.

Start engine. Set climate control temperature to its lowest setting. Set fan speed to its lowest setting. Set airflow direction to the dash vents only. Activate recirculation and ECON modes.



Thoroughly shake a 100ml bottle of treatment and empty the bottle into the filling chamber. Connect the outlet tube.





Place the cleaning unit into the passenger footwell, making certain that the unit is as level as possible. Connect the power cord and route it through a slightly opened window. The remaining windows and sunroof should be completely closed.



Switch unit on and position the outlet tube such that the vapor is drawn into the recirculation air intake, generally in the passenger footwell area. Refer to the appropriate repair information for exact location. Close all doors. The atomized cleaning fluid will begin coming out of the vents. After about 15-20 minutes the treatment stops automatically.

If the vehicle is an Audi Q7 with 4 zone climate control the rear A/C unit is to be treated as well. Repeat the procedure for the rear A/C unit. Use the same A/C settings as was used for the front A/C unit. Position the outlet tube toward the vent on the left of the rear compartment.



Air out the vehicle after the procedure for about 10 minutes.

Instructions for unit maintenance after each use can be found in the Aircomatic® manual.

[RTexasF]

The cabin filter on my '04 was totally foul @ 11K miles. Apparently you have the original still in there @ 20K. Start there as you suggested.

[Trip]

If there's something funky in the HVAC system, do you really want to be breathing it over and over again? And if there is an odor, what good would it do to keep fresh air out? Keep fresh air mode on so any particulates in the cabin vent out and are not recirculated. The cabin filter does not help clean the cabin air in recirc mode and even if it did, unless a Hepta or charcoal filter is used, its not going to filter out mold particles or the like. Even your manual says "The system should be left in fresh air mode under almost all conditions." (Page 105 of the owner's manual for my 2006). It goes on to say you can use recirc mode for dusty/smoky situations, but fresh air should be routed thru the system again when possible.

Also, I had read somewhere that leaving the recirc mode on for extended periods while using the A/C at max could actually cause frost build up on some components under the dash. I remember it saying that the frost could then melt and the water could cause other problems as well - leaking on sensitive electronic components or leaving moist areas for mold to grow.

[Foreign_Wide]

Just to add to the discussion, similar issues are in residential settings. I come across this in my work.

http://www.moldinspector.com/air_conditioning_mold.htm

[IonFizzle]

Wow, this is an excellent forum. Thank you all for well-informed, rational advice. I will buy the cabin filter today and switch it, then attempt other solutions if that doesn't solve the problem.

[zroger73]

Originally Posted by Trip

The cabin filter does not help clean the cabin air in recirc mode and even if it did, unless a Hepta or charcoal filter is used, its not going to filter out mold particles or the like.

Actually, our filters DO filter both outside air and recirculated air. Some other, if not most, systems filter only outside air.

[Trip]

Originally Posted by zroger73

Actually, our filters DO filter both outside air and recirculated air. Some other, if not most, systems filter only outside air.

Are you sure about that? I think the recirc point is after the filter. When I was putting the V6 strut bar on my car, I could clearly see the filter under the base of the windshield suggesting that the airflow from the outside would be cut off 'under' the filter. If recirc air is directed thru the filter, it would have to pick up fresh air, too, defeating the purpose. I'm pretty sure recirc air is taken in from the passenger footwell area, again indicating the recirc point is after the filter.

[James.uk]

In the UK we can buy "Anti bac" sprays for air con units in cars, as its poss to get some very unpleasant viruses from them if the filters are neglected, Legeionaires (?) disease being one of them..
.

[Foreign_Wide]

That's true James.

I had a mold case in a vacant house I was selling for a relo company. The bottom line is that your basement, or whatever area has a mold issue, needs to be at or below 40% relative humidity to discourage mold growth.

Knowing that, maybe those that have clogged drainage in the A/C units are at risk?

[reaquino]

The preventive solution is rather simple. Before pulling into your garage, turn off the AC and run for at least 30s before turning off the car. If you remember to do it a few blocks away before stopping the car you should be fine.

This dries out the system.

Jay