mildew smell from ventilation system

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bruin nut

Well-known member
Joined
Aug 12, 2013
Messages
84
In the last week, there's been a discernible mildew smell, especially upon beginning a drive, coming from the vents. Any advice?
 
This has been noticed before by others. May be the design of the a/c system. If you can figure out where the air intake for the a/c is, try running the a/c on recirc and spray some Lysol into the intake and let it run for a while.
 
Every make has been having issues with it lately. They best thing to do is try and turn off the ac a few min before home, this should dry out the evaporator. If you want something to get rid of the smell go to your local Mercedes dealer and ask for a bottle of "contra-sept". It will take the smell away, you just have to spray it on the evap.
 
Official Explanation from Toyota:

http://toyota.custhelp.com/app/answers/detail/a_id/7682/~/what-causes-air-conditioner-odor%3F-how-can-i-prevent-the-odor-from-occurring%3F

Also, a thread on PriusChat regarding the smell. Not unique to our vehicles, but seems to be prevalent with the HVAC system in Toyotas. I wonder if Lexus has the same problems?

http://priuschat.com/threads/musty-smell-from-a-c-system.46571/

I have tried the alcohol blowout described on PriusChat with some success (which was referenced from Toyota, but I can no longer find that). Basically, turn the fan on full blast, fresh air on, A/C off. Then with a 1:5 isopropyl alcohol to water solution in a bottle, spray directly into the air intake located at the base of the windshield, both above and beneath the hood. Spray lots of it in there and then spray some more so that the fan can suck the alcohol into the evaporator. I am unsure if there the cabin filter will block that solution so you may want to remove that prior to spraying. Your car will smell of alcohol immediately following this. You might want to ventilate at this point. a cheap way to disinfect your evaporator.


it seems to work. also, making sure that the A/C is off a few minutes prior to arriving to your destination with the fresh air enabled (no recirculation) will help dry out the evaporator and reduce the ability for mold and mildew to grow.
 
I had the same problem on my 2002 Camry and 2011 Sienna.

If you can turn off the AC a couple of minutes before your destination you will dry out the evaporator. I probably only remember one out of three times but that seems to be enough to keep it under control in my other Toyotas. I have not noticed it in the Rav4 yet.

Mike
 
The problem just started about 2 weeks ago, coinciding with a nasty heat wave in SoCal. It goes away after a few minutes, but the smell is pretty bad. I've never had this in any other car I've owned. This is my first Toyota.

I got home a little while ago, left the car on in the garage, and put the vent on full with recirculation. I then sprayed in the alcohol mixture recommended above. Sure enough, the alcohol smell came through the vents. I repeated it 2 times, then let it run for another 10 minutes. I'll report back later with the results.

Thanks for all the advice.
 
Brand new 2014 Rav4 with 5,000 miles. Mildew odor started after a couple car washes, but no idea if that's related. Garage kept. Smell starts coming out of vents about 20 seconds after start up and tends to go away after 5 minutes, or we just get more used to it. Glad to hear that this is a common problem but as others have posted, this is the only car I've ever owned with this issue. It isn't normal, it's probably not healthy, and we shouldn't have to accept it. Took it to the dealer this morning and they blew out the cabin air filter and said to drive it with the A/C off so the vents can dry out. That's not a fix in my book.
 
If you turn off the A/C 5 minutes before you get home, it won't develop the smell overnight and blow it in your face in the morning.
 
BillH442 said:
Brand new 2014 Rav4 with 5,000 miles. Mildew odor started after a couple car washes, but no idea if that's related. Garage kept. Smell starts coming out of vents about 20 seconds after start up and tends to go away after 5 minutes, or we just get more used to it. Glad to hear that this is a common problem but as others have posted, this is the only car I've ever owned with this issue. It isn't normal, it's probably not healthy, and we shouldn't have to accept it. Took it to the dealer this morning and they blew out the cabin air filter and said to drive it with the A/C off so the vents can dry out. That's not a fix in my book.

I had the same thing happen. I took it to Carson Toyota 2 months ago for the 10 k service. Service was great, but the mildew fix was exactly what they told you. I agree this is not a fix at all. Simply put, the ventilation system should never blow mildew air no matter the conditions. This must be a design defect with certain Toyota products. I've tried the solution in this thread and it works for a few days before the mildew smell comes back. It's not awful, just unpleasant for a couple minutes. It's also kind of embarrassing when someone is in your car and says "what's that smell?"
 
I bought a $2 dollar spray bottle of all-purpose Lysol spray and it worked like a charm! Turn the fans to full blast, and I even opened all the doors to air out the car. Sprayed generously into the intake vent. It's in front of the windshield on the right side of the car. Forgot if I opened the hood or not. Air out for 5-10 minutes or so, then I sprayed it again, then air out.
I had massive mildew smell at the beginning of summer. It was so bad I was getting nauseous and burning up because they tell you to turn off the A/C. I went in for my 5k service and they told me the same stuff as mentioned in previous posts.
I only did the spray once and I haven't noticed the mildew smell since. I never bothered with "turn off a/c 5 minutes before parking" BS.
Good luck!
 
New 2015 Rav4 Limited with less than 5k miles. Mildew smell started within a month of purchase and hasn't diminished at all. It is there any time I use the ventilation system (A/C, Heat, Air Exchange). The smell is nauseating. I must open a window to dissipate the fumes. This doesn't work so well in inclement weather conditions. (This is the only car I have owned to ever have this issue.)

I spoke to the Toyota service guy today. He'd prefer I deal w/this on my own, but if necessary he offered to flush the air system with something to get rid of the smell. I haven't been able to deal with this on my own. Has anyone else had their air system flushed? If so, did it work?

(I should add that I am not willing to cover up the smell w/Lysol or any other spray because it's just masking the problem...not addressing it. And I agree that this is a serious design flaw. Toyota should own it & fix it IMHO)
 
I've not had the mildew smell problem, but I do have a different dilemma: a rat took up residence for a while in the trough that spans the windshield and contains the air intake vents. Rat is now gone, but the funk left behind perfumes the car whenever I open the vents, and is intolerable if I run the fan or A/C. I've read the posts about using an alcohol/water spray, and Lysol to disinfect the A/C evaporator. Any other suggestions for handling this problem?
 
Reddy-set said:
I've not had the mildew smell problem, but I do have a different dilemma: a rat took up residence for a while in the trough that spans the windshield and contains the air intake vents. Rat is now gone, but the funk left behind perfumes the car whenever I open the vents, and is intolerable if I run the fan or A/C. I've read the posts about using an alcohol/water spray, and Lysol to disinfect the A/C evaporator. Any other suggestions for handling this problem?
I helped a friend clean out his prius duct work. A rat had given birth and the litle ones died.
What a foul smell, we had to take the whole dashboard out of the prius to get to the duct work where the remains were.
I hope you don't have a similar situation
 
fromport said:
Reddy-set said:
I've not had the mildew smell problem, but I do have a different dilemma: a rat took up residence for a while in the trough that spans the windshield and contains the air intake vents. Rat is now gone, but the funk left behind perfumes the car whenever I open the vents, and is intolerable if I run the fan or A/C. I've read the posts about using an alcohol/water spray, and Lysol to disinfect the A/C evaporator. Any other suggestions for handling this problem?
I helped a friend clean out his prius duct work. A rat had given birth and the litle ones died.
What a foul smell, we had to take the whole dashboard out of the prius to get to the duct work where the remains were.
I hope you don't have a similar situation

Tried the alcohol blow-out today, even removed the cabin air filter and misted directly over the intake fan. This helped somewhat with the stink, but it still lingers. I also did a strong water rinse into the cowling with the air intakes and tea colored water drained onto the ground. At this point I plan to try a repetition tomorrow... hope like anything I don't need to physically get into the duct work. I'm pretty certain there is no critter there, just stench that comes out regardless of the vent setting.
 
When I first purchased the Rav4 I had this issue. It was pretty strong and almost always occurred after running AC. Even turning it off and driving 5-10 minutes with just the vent open to try and prevent it. I ended up replacing the air filter (was dirty and inefficient) and used an air hose and blowing out the drain tube. I didn't have two sets of eyes but after clearing the drain tube the issue has been resolved. I get a slight whiff every now and then but nothing compared to buying it last year.

I also run my ac in the car 24/7 in auto 70 degrees due to pack heat and quick charging.
 
co2112 said:
When I first purchased the Rav4 I had this issue. It was pretty strong and almost always occurred after running AC. Even turning it off and driving 5-10 minutes with just the vent open to try and prevent it. I ended up replacing the air filter (was dirty and inefficient) and used an air hose and blowing out the drain tube. I didn't have two eyes but after clearing the drain tube the issue has been resolved. I get a slight whiff every now and then but nothing compared to buying it last year.

I also run my ac in the car 24/7 in auto 70 degrees due to pack heat and quick charging.
Where did you access the drain tube?
 
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