Odd smell from ducts after using vent after A/C

This is normal. You are smelling the condensation that had built up in the evaporator and is now evaporating.

 

Oh it's a little worse than that. It becomes a breeding ground for MOLD! That is what you start smelling if you use the AC regularly. I find when I have to go with A/C I plan ahead and when close to my destination I shut off the A/C, open the vents and at least 1 window, throw the fan on high. I dry out most of the moisture in the vents , thus denying the breeding mold the thing it needs most, warm moisture!
One typical, but ineffectual fix is to shoot Lysol into the vents to kill the mold.
All it really does is make the car smell like LYSOL!
This trick seems to work best in the southwest where our humidity levels are pretty much in the low numbers!

 

Really common problem. There is little blending with fresh air in re-cirulate so the e-coil under the dash never airs out and you park it with a soaking wet e-coil and mold grows quite quickly. If you have allergies to mold it will start to bother you. The reason you don't smell it with the ac on is the coil quickly becomes soaked and it's covering all mold growth.Once you can smell it then it becomes quite stinky.

You can spray anything you want into the vents and it will do nothing but smell up your car for a while. You have to address the mold in the e-coil under the dash. The way the dealer fixes it they sell/ use a 2 spray can kit. One can is the cleaner and comes with a special little adapter hose they hook to the condensate drip tube under the car. They shoot that can full of pressurized microbial cleaner up that tube into the e-coil box filling that box with foamy cleaner. It goes from foam to liquid and then drips back out the tube. The other can is just perfume and to me really stinks bad. They shoot that can into the fresh air dam under the windshield. I don't use that second can of perfume. It stinks worse then the mold. The kit costs $25 over the parts counter to you and I have done it twice on my Gen II. It's easy you just have to be able to get all the way under the car to reach the condensate tube. Requires putting the car up. It kills the mold pretty good and if you vent like KK6PD says it will last about a year stink free.

The dealer charges $100 for this service p&L.

 

This should not be happening -- you may have something stuck in the drain or maybe the filter. Take a look at the filter and see how it looks - I'm not sure if you can see the evaporator when the filter is out .. but take a look. Do you use the AC all the time? You will often have this problem if you do not -- those that always use the AC are continually washing impurities out of the system ... when you use the AC it is surprising how dry the inside of the box actually is when the system is operating correctly.

You can use the sprays -- they need to be done correctly and a new filter installed

 

Oh its happening. Wev'e been talking about this on the Gen II site now for about 5 years. In fact there's a TSB out for replacing the e-coil. Its a very common issue with the Gen II Prius. Thats why the dealer offers the fix I posted.

Don't have a clue what your talking about how dry the box is???? Because you may have noticed all the water streaming out the condensate tube under the car like all cars because the box os soaked. The box is anything but dry. Thats how air conditioners work.

Here's the TSB for the Gen II:
New TSB (Sept 2009) Evaporator Coil Replacement for stinky or moldy Prius | PriusChat

 

I'm not saying this is not happening - I am saying that it is not normal ... unless a design is allowing water to stay in the box or the design easily allows foreign matter to block the pathway for the water to get out. You are not helping anything by trying to dry out the inside of the box .... unless you are in a very dry climate ... and then you wont have much water to begin with. The air leaving the evaporator is very dry - but cold ..... when you turn off the compressor and the evaporator gets above the dew point you actually start to move the water from the lower part of the system to the upper parts ... and depending on how long you run it the cold vents will become wet.

I would not shut the system down early.

Try running the AC on "auto" all the time for a couple of weeks and see if you can flush out what is in the system -- You may also notice the whole car may smell better. All my cars are alway on "auto"

This is a common problem in the northeast in the winter -- if you use the"auto" setting your car will be dehumidified even while heating the car and will be fresher smelling as the interior is not always subjected to damp conditions.

 

The OP here is talking about a TEMPORARY musty smell after switching from A/C to vent. Do the members saying he has a mold problem understand this? I feel this is normal.

 

Its very normal for a Prius to have this issue and its not temporary. If you have been on this site for more than a month you would have seen over the years hundreds of posts complaining of smelly ac.
Its very easy to understand whats happening if you know how an ac unit works.There's nothing to flush out.

The e-coil under the dash on a normal working car is usually soaked in condensate when the ac is on. If the e-coil is not wet that means no heat exchange is happening. That's why the CONDENSATE DRIP TUBE under your car drips constantly. In a Prius when your in RE-CIRCULATE there is no outside air coming in. The door that lets OUTSIDE AIR come in is closed. Unlike alot of other cars that do not do such a strict air channeling there is usually some blending of re-circ and outside air. Not in a prius and not usually in a car with an interior cabin filter. If you park your Prius with a soaked e-coil day after day with the outside air door closed mold will eventually grow on the e-coil. One way to help prevent that is do a dry out routine like KKCPD advises before you park (this works the best) or at the very least when you park put the ac in FRESH AIR mode a which opens the outside air door and gives it a chance to air out and not sit soaked. I use this method and its good for about 6-10 months before it smells again. I do not smoke. My ac is on everyday 52 weeks a year.

Once the Prius owner smells "gym socks" it will only get worse and the e-coil box must be cleaned using the method I described either by yourself at home or the dealer.
That method is used for alot of modern cars. If you have a cabin filter your usually doing strict air control.

The TSB for under dash e-coil replacement to address MOLD SMELL is made out of different metals that help retard mold growth but no one has ever posted back and said they are mold free after a replacement. I would rather clean my ac once a year than let a dealer rip my dash apart and all the problems that would cause down the road. I have a rattle free car and want to keep it that way.

 

The OP clearly states the smell goes away until the next time he switches to vent AFTER the A/C was on, as in the smell is temporary. I'm not saying there isn't a problem with some cars, but, it sounds like he is talking about smelling the condensate that is evaporating off of the now warm e-coil.

 

Maybe it's just where I live but I've smelled what you are talking about in pretty much every vehicle I've ever owned at some point or another. And personally I don't think it's a huge deal otherwise Toyota would be addressing it...at least in the manual.

 

I know exactly how and AC works -- and yes the coils self clean -- they are washed by the condensation coming off the coils. The filters are very good in most cars -- but dust still gets past and will sit on the coil -- if this is allowed to remain and build up you can have a problem. It does look as though Toyota has a design problem with some of the climate boxes -- and you most likely will have to do some cleaning if this is the cause.But we have found that by using the system continuously the problem is reduced. Obviously this is not going to fix a situation that is not caused from the slight build up on the coil or bottom of the the box

 

this is my second new car and same issue as the first one. "Dirty socks" is harsh, but I can relate. From my experiences, this condition develops over time with heavy AC use. Actually I just started noticing it on my Pri maybe 2 or 3 weeks ago (and in primetime AC) for the first time and this is my first summer with the car. At least this time around I have an idea of what is going on. I think shutting off the AC prior to destination with a high blower or opening external vents before shutoff (as mentioned above by ed) are the best medicine if you can police yourself...but challenging to do in practice.

However I also agree that the average joe should not have to do this to avoid the problem.

 

To I think answer the critics. When you use the fan with A/C off you don't "smell" anything because the evaporator is dry. You can't really smell dry mold, but you can still have mold. When you run the A/C everything gets wet. You'll see a puddle of water under every single car ever made that was running their A/C in the summer. When you shut off the A/C the evaporator starts to dry off as does anything that is wet when you run a big fan over it. As it dries you will smell the moist moldy stuff. Go into any damp basement and take a whiff. It will be musty smelling until it finally is completely dried off (unless you are sensitive to mold, then you can probably still detect it).

I'm wondering if anyone knows if there is an over the counter can of whatever foaming stuff they use, instead of paying $25...

To people saying they are self cleaning.. I'm guessing you never looked inside an ice machine before, which btw uses a lot more water (chlorinated at that) and has physical abrasion of hard ice cubes. And that is a lot more water flow than the A/C dripping. And those still build up mold.

 

Pull the air filter - there are more than a few here who found rat nests in the system - it's easy for them to get into...