AC/Defroster Moldy Smell SOLUTION

nate70500

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Just figured I'd share my solution to this problem as many people seem to have it and there wasn't too much definitive info out there, just a bunch of bits and pieces everywhere.
Whenever i would run my AC or defroster in my car, I got a musty/moldy smell. You become immune to it after a while but everyone who rides in my car notices. Dealership just gave me the usual answer of replacing the cabin air filter. I tried this but it did not solve my issue.
After some research, it seemed that the issue was due to mold in my AC evaporator and/or in the hoses for it. I went to NAPA and bought some A/C Pro Auto Air Conditioning Evaporator Odor Eliminator (UPC: 048168025671). It was about $10. It is a foaming cleaner in an aerosol can with a cap/tube attachment. I also purchased a new cabin air filter since youre supposed to replace it when using the AC Evap Cleaner.
The cleaner is simple, spray it through the AC Evap drain tube til it starts to foam back out the end of the tube. There are 2 ways to access the drain tube, from under the car or under the carpeting on the passenger side.
If you access it from underneath the car, you will need to lift the car up to be able to reach the drain tube. it is located almost directly underneath where the shifter is, slightly off to the passenger side. Insert the hose for the cleaner as far as possible and spray it up into there,
I chose to access it from inside the car where it comes through the firewall. To get to it, you need to go thru the passenger side front door. Pull down the carpeting paneling stuff along the side of the center console, starting from the front of the car to the end of the first piece of carpeting. It is pretty easy to pop back into place as it bends so don't worry. There will be a black rubber hose behind there (its the only hose there). You have to roll back the rubber hose from the front to the back after removing the 2 little rubber tabs on the hose. Insert the hose for the foaming cleaner into the part going into the firewall as far as possible and spray the cleaner through. Quickly slide the hose back over the end and re-secure it, you wont need to access this again so you can close it all up while the cleaner sits.
Then you let it sit for about 15 mins (it will begin to drain out the AC evap drain tube out onto the ground almost immediately, so if you don't want it all over your garage floor use a bucket or do it outside!). Then you let your fan run on the lowest setting for 5 minutes (I let it run for 25 mins after that with the system on full blast after that and doors open to get rid of the smell of the cleaner, but it int a bad smell at all).
The final step is to replace your cabin air filter. Open the glove box. There are four screws around the glove box holding it in. After undoing those screws, you can pull the whole glove box assembly right out. Be careful though, there is a light attached to the top of the glove box you need to unplug before you completely remove the glove box. The filter is right there behind a rectangular panel that just unclips and drops down.
I would also recommend having your local dealership turn on the after blower feature on your car if you have this issue, it'll help stop the build up of condensation causing the mold. It just runs the blower fan for a few mins after you turn off your car to dry out the AC Evap. I hope this helps, wish all this was in one thread when I was trying to do mine! I had a faint smell of cleaner for the first day or two. But its been over a month and no more bad smells, just cool air!
 
With my past few cars I've gotten in the habit of turning off the AC when a few minutes from home/done driving for the day. Maybe I'll ask the dealer to enable the after blower feature.

Great post, thanks for figuring all this out and sharing. 🙂
 
With my past few cars I've gotten in the habit of turning off the AC when a few minutes from home/done driving for the day. Maybe I'll ask the dealer to enable the after blower feature.

Great post, thanks for figuring all this out and sharing. 🙂

No problem! I plan on sharing all my projects on my car seeing as there aren't many people out there doing it. Gotta share what I know and help people out!
 
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Wow, great post. Just picked up new Fram cabin filters for my Regal and my wife's Verano. Both cars have the smell you are talking about occasionally, kind of like a vinegar smell. I was hoping the filters would do the trick, but I will definitely do your method now. It also seems like after doing this I should definitely have the dealer turn on the after blower. This might solve the smell once and for all.
 
With my past few cars I've gotten in the habit of turning off the AC when a few minutes from home/done driving for the day. Maybe I'll ask the dealer to enable the after blower feature.

Great post, thanks for figuring all this out and sharing. 🙂

I will have to try this that smell is just terrible

Wow, great post. Just picked up new Fram cabin filters for my Regal and my wife's Verano. Both cars have the smell you are talking about occasionally, kind of like a vinegar smell. I was hoping the filters would do the trick, but I will definitely do your method now. It also seems like after doing this I should definitely have the dealer turn on the after blower. This might solve the smell once and for all.

Thank you for the post, nate70500!

stoopid, Jscaife, and alphabets, we hope the information helps correct the concerns you have in your Buick vehicles. If you would like an additional layer of assistance for a visit to a dealership, or have any related questions or concerns, please don't hesitate to send our team a private message. We are happy to document any feedback in our system as well.

We appreciate you all taking the time to reach out.

Amanda K.
Buick Customer Care
 
Thank you for the post, nate70500!

stoopid, Jscaife, and alphabets, we hope the information helps correct the concerns you have in your Buick vehicles. If you would like an additional layer of assistance for a visit to a dealership, or have any related questions or concerns, please don't hesitate to send our team a private message. We are happy to document any feedback in our system as well.

We appreciate you all taking the time to reach out.

Amanda K.
Buick Customer Care

Thanks Amanda. Just to be clear - I haven't had this issue with the Regal (yet), perhaps because of what I said I do. I also don't live somewhere I have to run the AC a lot/daily.
 
I literally just did this with the same product last weekend. So far so good. The only issue I had was the cleaner not reaching the top of the evaporator core. So I took out the air temp sensor and shoved the hose up there. The cleaner actually smells kinda nice haha
 
Great info, I have this smell and will definitely do this! Does anyone happen to have any pics of these hoses? Sounds pretty self explanatory, but I am a visual learner. If not I will try to take pics when I do it.
 
Great info, I have this smell and will definitely do this! Does anyone happen to have any pics of these hoses? Sounds pretty self explanatory, but I am a visual learner. If not I will try to take pics when I do it.

I forgot to take pics as I was doing it. It shouldn't be hard to find the hose ito the only one there
 
GM Service Bulletin Number 99-01-39-004F Printed this document and made an appointment for service, 2.5 hours to complete and so far smell is completely gone. The Buick service rep was not aware of the bulletin information and had to show this document to the Service manager and master technician to proceed. 4th Visit to this Buick Dealer and I very impressed with the service and attitude of all the staff from the moment you drive into the service bay. AC Hvac Bulletin 99 01039 004F page 1 or 2.webpAc Hvac page 2 of 2.webp
 
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i take it that was all done on warranty?
thankfully my '12 doesnt have this problem
 
This is a great thread and something I have been dealing with. When I switch off the AC while driving it stinks for quite some time after. Did anyone get the fix covered under warranty? I have a GMPP warranty.
 
You may want to get the service bulletin in post#12 and then contact your dealer, the bullentin is for 2015 and older so you'll have to see if it applies still and warranty covered.
 
You may want to get the service bulletin in post#12 and then contact your dealer, the bullentin is for 2015 and older so you'll have to see if it applies still and warranty covered.
May be a stupid question, but since there is a service bulletin, does that mean the repair is completely covered by the dealership?
 
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If your car is still under full warranty, if not mostly likely not. On the long shot some may be willing to do it, but its better to ask as it's not something that is always clear. Sorry to be vague, but it's a simple call to the dealer just to confirm.
 
If your car is still under full warranty, if not mostly likely not. On the long shot some may be willing to do it, but its better to ask as it's not something that is always clear. Sorry to be vague, but it's a simple call to the dealer just to confirm.
No, just power train (2014). Also, my wife's verano (2013). Yes, i will call and bring up the bulletin and ask what they can do for me. We both have the smell.
 
Knock on wood. I haven't had this issue with my car. I have had it with a previous car but they turned on the blower feature and it solved the problem.
 
If your car is still under full warranty, if not mostly likely not. On the long shot some may be willing to do it, but its better to ask as it's not something that is always clear. Sorry to be vague, but it's a simple call to the dealer just to confirm.

Service bulletins are not covered under warranty if its a service like this. The warranty only covers parts & labor if a part that falls is listed under the warranty coverage.

Recalls are the only repair the dealer will cover, even if the car is out of warranty.
 
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