Musty Smell in Vent Position

[mookie]

I get a musty smell when I put my HVAC control to the "Vent" position. I don't get it when in "AC" or "Max AC".



I was getting a musty smell in the "AC" modes and had the "AC deoderized" (service manager's description). That eliminated the smell. Then weeks later it showed up in the "Vent" position.



I've tried spraying Ozium in front of the windshield with the fan blowing with vent on.

I've tried spraying Ozium through the return in the passenger footwell.



My question is: Does anybody know what part of the ducting is different to the two separate functions. To put it another way, what needs to be cleaned to get rid of the smell? Does there have to be two different deoderizing operations to do both systems?



I want to be able to suggest something to the dealer as this will be the 3rd time it will be in for the musty smell.



Thanks.

 

[Michael Cacioppo]

Mookie, I don't know a definitive answer, but there should be a seperate section of duct that is attached to the heater core which will be closed off in the A/C max and A/C mode if the contol is on coldest. See if the smell occurs in A/C (not max) with the heater control on hot (all the way to the right). This may give you a clue.

 

[mookie]

OK, I'll try that.



I'll report back later today (around 6 or 7pm Eastern time).

 

[TRACket Paul]

Mookie, check the AC folder in my library for more info.

 

[mookie]

MikeC,



I tested like you said and I only got the musty smell in Vent/Panel with or without heat.



Paul,



Thanks for the info; I saved it to my computer.

 

[Dre L]

I bought this AC deodorizer, did a pretty good job since it is a high pressure spray and really mists itself throughout the system.



First I turned off the system completely, and sprayed a good shot in each vent. You'll see it mist out of other vents.



Then I sprayed a shot in the front intakes at the bottom of the windshield.



I left it for about 10 minutes.



Then I turned on the system to fresh air no AC with a slow fan #1.



Shot a couple of good sprays in each front intake.



Set it to norm AC.



Blasted the living **** out of the front intakes.



let it run for a bit.



Turned it off.



Blasted the rest of the can into the vents and front intakes.



Left it on vent open all night to "disinfect".



Turned it on the next morning, smelled great.



Turned it to max ac and drove smelled great... parked, turned it off. Came back turned it on, stunk again :angry:





Best advice is to turn off the AC and let it dry out for a bit before you stop / park.



I have been trying this formula which seems to work very well... Use Max AC to cool down fast, then use Norm AC for the remainder of your ride. Norm AC seems to allow the AC system to dry off with fresh air, rather than collect stagnant water, and rebreathed air, which causes smells.



Haven't had a stinky startup in weeks.



Oh, and when it does stink, blasting the system on Max HOT vent and/or defrost cleans out the smell.

 

[mookie]

Thanks, Nobleman.



I got it set up at the dealer. Dropping it off Monday night so the dealer can work on it on Tuesday. Under warranty including car rental.



We'll see if they can do it.

 

[William Washington]

Once it's cured, try to remember to turn off your air conditioning a few minutes before you shut down the car and let it run on vent for a while to dry out the ducts. Otherwhise, the problem will jjust return.



Or move to Arizona! It's a dry heat!

 

[Fer Echegaray]

We had the same problem on another car, and we only got rid of it by letting the full hot air run for like 5 minutes a couple of times with some lysol sprayed on the intake vents..



Do as wwashing says, no matter how good of a job the dealer does, if there's humidity when the truck is turned off you will eventually get the smell back. We follow the above guideline and the smell has not returned.

 

[mookie]

I'm developing that habit of turning to vent as I'm nearing my destination, now.



Thanks for the input!

 

[Bill V]

Musty Smell in Vent Position

You're talking about your Sport Trac, right? Otherwise, this sounds more like a personal hygiene issue. :lol:

 

[Mike Wilson]

Nobleman and Mookie have good advice!

Turn off your A/C just before you reach your destination, and let the outside air run

throught the vents and system to get out all of the cold, wet, condensed, damp air

before you turn off your truck and let it sit there all day. It can only cause a "skunky"

smell! This has worked for my '05!

Turn the fan on high for the last minute or two of your trip, also, to make sure all of the

moisture and humidity are blown out of your vents/duct system!

Again, worked well for mine, with the same problem!

 

[Nelson Atwell]

I guess this is just a problem in high humidity areas, since I haven't experienced this.



When I first read the title, I thought it was referring to the vent position on the rear window. Depending on what you're hauling in the bed (wet dog, manure, etc.), you could get a very musty smell.

 

[Dre L]

Norm AC does not seem to be affected though. I guess it creates less condensation since there is a constant flow of fresh air.



It's not as cold, but I have been having a lot less issues running on Norm AC.

 

[Dre L]

I stand corrected, it has gotten a bit muggier out today, and it is slightly smelly after driving around with norm ac. Stick to drying it out before you park.



I read this once, haven't had the time to inquire of the dealer though...

Ford offers a Purge Module for many of their cars to attack the problem. What it does is to cycle the blower motor to dry out the evaporator for a period of time after the engine is shut off. The module will work for most Ford cars, but it requires a special harness depending on the type of electrical system used in the air conditioning in the particular car. The part number for the module is F8ZX-19980-AA and you can inquire about it at your local Ford dealer.

I'm seriously interested if it will give me some summertime sanity.

 

[mookie]

Nobleman,



Thanks, I'll keep that number handy if the deocerization process doesn't work.

 

[TRACket Paul]

GM had a similar problem and solution (fan cycling) on late model Impalas. They had a TSB issued.

 

[TRACket Paul]

I checked on the Purge Module #F8ZX-19980-AA at my nearby dealer. They were not able to track it down, they said it was an engineering number not a part number.