Taking a Stand on 2007 Prius AC Mold Problem!

I have a 2007 Mercedes E 320 CDI that has this same problem.

 

Engine Block Heater

 

I agree and it would be brainless to add proper ACCESS PORTS in the case to allow easy access to the e-coil. I was able to borrow a *very* expensive fibre optic inspection scope from work and gingerly drill a tiny hole into the case. Verifying I had clearance, I drilled a couple of 1/2 inch holes to allow me to spray the hell out of the e-coil

Why 1/2 you ask? Because that is a *very* common electrical knockout size. Knockout plugs are easily and cheaply available at jobbers and most big box stores

When I inspected the e-coil with my fibre optic scope, there was no indication of actual dirt or mold buildup. That's common though, the stinky stuff is usually invisible to the naked eye

I chose to use NuCalgon EvapFresh as I have seen this product used a lot in commercial, institutional, and industrial settings, and trust it

Nu-Calgon Wholesaler Inc. : Products : Evap-Fresh

Unlike other products that claim to offer disinfection, EvapFresh is EPA certified to do so. It also doesn't leave behind a perfumey or hospital ward smell

I actually had to treat my Prius e-coil twice. The first time there was still a hint of the stench, so I zapped it again. That fixed it. I used a common garden poly sprayer, the kind with the pump in the handle and the wand. I only use it for servicing my e-coils in my two homes, it never has any other chemical in it

Similar issues exist with home A/C that use the most efficient variable speed air handlers and outdoor condensers. I have a Bryant Evolution system at my hobby farm and at my house. The outdoor condenser is two speed, the furnace fan is variable speed

With a thermal expansion valve in the evaporator, the system is designed to run constantly at the lowest speed. This enhances moisture removal as the air spends more time at the e-coil. Our summers are brief but very muggy

I have to clean the e-coils in my Bryant units at least once a year or the stench returns. Of course, depending on what sort of molds are in the environment, you can expect to frequently clean the coils

So far my Prius has remained funk-free. However, the temps soared to +33 C over Canada Day here, and I noticed at the hobby farm my FJ is starting to stink. Not bad yet, but that familiar crotch odor is starting

I'm not going to monkey around with the fibre optic scope this time. I'll try to drop the fan first, as it's easy to get to on the FJ. If I can't get to the e-coil from there, I'll go through the grommet at the firewall

 

When this issue first popped up with the new high eff A/C units for homes, a few e-coils were replaced under warranty. I do know with Bryant, they prefer you clean the e-coil using the proper disinfectant

If the mold is already in the local environment, replacing the entire case will buy some time. But once the mold establishes itself again?

 

I tried to snoop around their website, but apparently there is no requirement to report ingredients, like MSDS requires here. Without directly contacting the e-coil, I wonder how effectively it cleans?

FWIW here is the proper way to clean an e-coil, to wipe out the widest range of icky things:

First, the coil must be squeaky clean. No sense spraying a disinfectant on the e-coil if it's filthy, as molds can easily survive then. It's best to clean twice, using an alkaline cleaner, rinsing, and then an acidic cleaner

For example, NuCalgon CalBrite is an acidic cleaner but is relatively safe

Nu-Calgon Wholesaler Inc. : Products : Cal-Brite

NuCalgon Special HD CalClean is an alkaline cleaner that is quite safe when used according to directions

Nu-Calgon Wholesaler Inc. : Products : CalClean, Special HD

Once the e-coil has been rinsed and allowed to dry, use a combination light cleaner and disinfectant, like EvapFresh

Nu-Calgon Wholesaler Inc. : Products : Evap-Fresh

If the infestation is quite bad, you may have to follow up with a chlorine dioxide product, like BioFresh, which is also EPA certified for disinfection

Nu-Calgon Wholesaler Inc. : Products : Bio-Fresh cd

NuCalgon also recommends spraying a teflon product on the e-coil once it's dry. Their product is CalShield, it also works well on rads to make it easier to hose bugs off

Nu-Calgon Wholesaler Inc. : Products : Cal-Shield

It takes me about 1.5 hours to clean my house e-coil using the steps above. Of course, most of that time is waiting for the e-coil to dry. I only have to do this at the start of the A/C season

BioFresh can also be fogged into ductwork to take care of anything growing in there. No sense in cleaning and disinfecting the e-coil if the ductwork is filthy, and you get the same mold back next week

 

I'm happy to hear it worked out ok. Don't be surprised if you have to repeat the disinfection. Actually, it doesn't hurt to do so.

Over Canada Day I noticed our first really nasty muggy day, +33 C, my FJ started to stink. Instead of monkeying around with the fibre optic scope and drill bits, I'm going to also go through the firewall port

As a friendly reminder to anybody reading this thread, do NOT try household laundry bleach to disinfect your e-coil. Although the bleach will absolutely wipe out whatever is growing in your e-coil and case, you will probably ruin the e-coil.

Sodium hypochlorite is corrosive to copper and aluminum, typical components of an e-coil: aluminum for the fins, copper for the tubing. The metals will suffer severe corrosion, which will then give off a weird metallic odor

And never, EVER try to mix laundry bleach with ammonia, as you can form an explosive mixture. Never, ever, EVER mix bleach with acids like toilet bowl cleaner, hydrochloric acid, as you can expect copious amounts of chlorine gas. Any stunt like I have mentioned could very well kill you, or severely injure you, eg lung damage

 

Can you through a brother a bone and give a place to buy or a web site the sells.
thanks

 

Although we have not seen any 04-05 Prius with smells... my 97 Tacoma does get an odor now and then... I believe that some of the time, the odor is simply from too much humidity.... Bear in mind, that is only SOME ofthe time.

 

Thanks again jayman! Well done!
Having such good luck so far on the smell. The car smells really nice. And I do expect it to be an ongoing maint. issue. Probably monthly. Its just a little weird spraying liquid into the firewall and not really knowing where its going but i don't care. I'm desperate.
I going to try the Walk the Walk route though since THEBear has given me alot of hope there might be something fixable here. Thanks again Mr Bear.:yo: Awaiting a call back from my dealer about this. They've been calling me weekly for the last 5 months asking me to come if for an oil change so they can over fill my oil...underinflate my tires and maybe throw in a free door ding.:nono:
Since I actually have an issue I'm sure I'll never hear from them again.

 

On July 2, my 2006 Prius started to smell like something crawled into the A/C and died. Started when I began a several hundred mile trip and ran the A/C all day due to high heat and humidity mix. Finally got home again, went to the dealer today (July 5) and got them to track things down. Evaporation box full of icky water, and the drain was clogged. Dealer unclogged drain line, foamed the box (see several posts above for this discussion).

Got home and called the corporate service number, and a kind person took down my info, the issue, the dealer's solution to the issue, and assigned a case number. The kind person also verified there were no open TSB for this issue.

I agree with OP - call and let the system know there is a problem. In my case, the drain line was clogged. This is an item I will be sure to have the dealer re-check every oil change.

 

As expected haven't heard a word from the dealer except a pre-recorded announcement that there's a sale going on. In fact the plea's for oil changes have stopped. If I had known a simple request for help would have stopped that I would have done that 5 months ago.
Maybe the guy that's in charge of door dings is on vacation so they can't get me in right now.

 

Thank you soooo much for posting this. I am tired of being treated like and idiot for complaining about this. My car from time to time smells like a dead cat and I know it is coming from the air system . It comes around after a rain or after the car wash and at other odd times. My car sat for a week at the airport while on vacation and it reeked! I had to ride home with the windows down it was so bad. I have changed all the filters and am looking for a good foaming antimold spray. Also, where is the best place to spray this stuff?

 

I called the number Walk listed. They started a case file. No one ever called but got a letter today from Kristie @ The Toyota Customer Care Experience Center saying they tried to reach me to no avail. Hmmm...the local dealer calls me all the time with sales promo's. I know there number by heart. They said the dealer would call me. I will call Corp. back today.

My hose down of the E-Coil through the firewall plug worked great for about a month. Smell although not anywhere as bad as it was is back. I must not of put enough cleaner in there. Its hard to gauge as you can't see or hear how much your spraying in there once the hose is in the firewall hole. Your spraying blind. Looks like its a monthly maint. I might have to take my car to the dealer so they can ozonate it...!!!!!!

The horror...

 

It really stinks doesn't it?
But Given your particular symptoms/complaint you might have an extra issue. Do you use the re-cycle air or inside cabin air only mode? if you use re-cycle that air is sampled from the front air dam under the front windshield wipers.That area on both sides is water vented to vents located behind each front wheel. Those vents might be clogged with leaf debris. Water will then back up and smell. To test get a hose with a controlled nozzle. Pour water into that front black plastic air dam not letting any water slosh over or go anywhere but in that dam and water should then pour out of the behind the wheel vents very easily. Those vents flow very good so should be strong flow not a little trickle.
Good luck.

 

For a bad case, you usually have to repeat the application. It's important to thouroughly saturate the e-coil. As you're spraying blind, you can't be certain you're getting the entire e-coil.

Although EvapFresh has a surfactant that will allow it to sheet and work its way down, it's best to have direct product application on the entire surface

It may not be a bad idea to first clean the e-coil with the cleaners I have previously mentioned. First the acid-based cleaner, then the alkaline-based cleaner, then the Evap-Fresh. That will erradicate the stuff

You may also have stuff growing in the plastic ductwork too. If your climate is very humid, it can be expected to have colonies growing in the ducting, so they will easily re-establish themselves once the e-coil gets clean

Nu-Calgon makes a product - BioFresh - that can be used for fogging ductwork. As it has chlorine dioxide, you must be careful with the seats and carpet. Any spills will tend to bleach the fabric

 

Thanks so much for this thread! I was wondering if this might be a common problem. I read most of the posts, but not all, so if I've repeated anything here, I apologize.
I have a 2008 with 3000 miles. I live in hot, Central Texas. I have been using the AC since about April, I guess. I first noticed an odor about two months ago, for about two minutes after starting up. I usually have the AC running with fresh air, but, with the 100 degree temps, I have been using the recirculating air setting.
I got on the forum yesterday and followed the great instructions that had been posted on how to remove/replace the cabin filter. I got the filter out and, except for a few loose specks of dirt, it looked like new. I also thought the condensate drain might be plugged up, so I checked that out and saw lots of water dripping out.
I called my dealer and talked to the service manager. He said to bring it in and they would replace the filter. I mentioned that I had only 3K miles on the car and had already checked the filter and it was clean. He said to bring it in anyway and they would take a look. I will do that next week and report back on their "remedy".
I have owned Fords, Pontiacs, a Cadillac, Mazda trucks, two Camrys, and presently also own an Avalon. None have exhibited this problem.
If no one else has pursued this approach, I will contact Consumer Reports and tell them of the problem. They have been big supporters of the Prius and maybe they can use their influence to get Toyota involved in pursuing a fix for this problem for present Prius owners.
Thanks again for this thread. Glad to know I'm not alone with this "dirty laundry" situation. I'm just surprised that it has been here so long with no fix.

 

I think this must be a normal problem in cars with A/C. Recently the A/C in my truck developed a leak in the evaporator, so I had to tear out the dash and change it. I had also in the last year or so noticed a moldy smell in my truck.

I opened up the heater-ventilation-A/C (HVAC) box and I didn't notice any mold on the evaporator at all, or in the HVAC box. However, there was a large damper that I believe is used for mixing the A/C cold air and the hot air from the heater which was covered with thick foam. The foam was impregnated with nasty green mildew. So I'm assuming that's where the smell was coming from. I took a bucket of water+bleach and washed everything down, and then really soaked and cleaned the damper well (probably should have bought a new one - but I wanted to get this job over with and the dealer parts counter was closed). Anyhow, after I got it all together and working again, my truck didn't smell after that. I don't know if a Prius has a similar foam covered damper - but that would be the first thing I'd look for.

When you run your A/C, water condenses on the evaporator and drips to the bottom of the HVAC box. There is a drain tube at the bottom that allows the water to drip out. That's why when you run your A/C, water drips out of the bottom of your car. If that tube gets clogged up, I could see a lot of moldy smelling water building up in there. It would be a good idea to check your A/C drain tube once in a while to make sure it isn't clogged. I have noticed that the drain tube in my Home A/C builds up mold every now and then and gets clogged and the water overflows from the system onto the floor, so I have to stuff a coat hanger up there and scrape it out. If you do that on your car, you may want to be extra careful, because if you puncture your evaporator, it's going to probably cost several thousand bucks to have it fixed.

Another thing is that if you normally park your car on a sloped surface, the water may accumulate in a corner of the box where it can't reach the drain tube. Over a long period of time, things might start to grow in that area. If that's the case, maybe someone should develop an "extra A/C drain tube" mod for the Prius. Alternately, you could figure out where the drain tube comes out of the HVAC box and make sure you park your car so that the tube is on the down side of the box so that the water runs out.

Mold reproduces by emitting spores that float in the air, so I doubt you're going to stop it from getting into your A/C system eventually. The fact that Toyota even puts an air filter in their HVAC system is a plus. Most manufacturers don't. It's hard to say whether that filter is effective in filtering out spores.

Anyhow, just some random thoughts...

 

[p'p

Common problem a to all car ac's? Not so much. I've owned alot of new and old cars in my 53 years and the Prius is unique.First new car that started stinking after a few months. Granted I did not do the venting and running the air on high heat every time I was done driving but I think
that should be unnecessary. Unfortunately I have found on this car if you don't do that it will continue to stink. Thanks to jayman I have had excellent results with spraying evap coil cleaner into the firewall rubber gap that the ac hi/low pipes go into.Hosing down the evap coil with anti bac cleaner.
Also if you search my last few threads I chased this issue through Corporate Toyota's recommendation and was sent back to the dealer for the ultimate fix which is a can of foaming cleaner thats injected from below into the drain tube. I have been very happy with Jaymans method ( he's the ac man!!!) so far and since I have sprayed the cleaner into the firewall and followed everyone's recommendation concerning to make sure I open up the re-circ door. So far it has not started stinking again. When it does I will do the dealer foam inject.
I too thought there was something going on in the evap housing that it was not allowing all the condensation to drain out but its more biological than that I think.
Whatever the issue is Toyota is not addressing an ultimate mechanical fix. I can see why. Something is not right down yonder in the e-vap housing. Can you imagine the cost cost of replacing thousands of evap housings in our cars? But, its too bad as its the only problem in an otherwise spectacular car. I really love this car too. But, the fact is if you live in a sub tropical state and use the ac everyday your car will smell bad unless you go to lengths to service it.
Oh btw, never ever use bleach in your car or home to clean ac components or anything near ac components. It will destroy the metals used in the evap coil and assoc. metals. Not to mention very bad for your health.

 

Yeah, the cost of fixing these things in retrospect would be horrendous. When I changed out the evaporator in my truck (which is 8 years old), after a week of studying the service manual, I started at 7AM in the morning and finished at 9PM, not stopping to eat or anything. It was a very tough job - makes you want to cry when you see your entire dash, steering wheel, etc laying there all over your garage floor. Not a job for the timid. I can see why Toyota is avoiding responsibility for this.

I did not use bleach* on my evaporator or heater core, since I changed both out and they were brand new. Just on the dampers and the inside walls of the HVAC box. *FYI, you drink bleach (chlorine) every day in your water, or swim in it in your pool. I diluted it with water - the amount I used was a little stronger than you'd use in your pool (not a lot). I would not hesitate to use it again, but you're right, I would not use it on metal HVAC components.

Anyhow, sounds like Jayman has a good way to manage the problem.

More on the lines of a fix, I was thinking about the air filter. Since few cars have an air filter, perhaps that is the problem. Maybe the air filter is holding the humidity in the HVAC box instead of allowing normal air currents to let it leak out. It seems like in a hot climate like Texas (I lived there for 18 years), the water would want to evaporate out when the car is parked in the sun - unless there were something obstructing the free flow of air like the air filter. Maybe the best thing to try in the way of a fix is to remove the air filter - or to use a filter more sparse than paper, like ordinary window screen (to keep the lint out). I'll bet that is where the real problem is... in fact, that HAS to be it.

When you start your car and turn on the A/C, what's the first air that comes out of the box? The air that was already in the box comes out and enters the cabin. If that were hot humid stinky mouldering air that was trapped in there, that's the first thing you'd smell until it cleared out of the cabin. What is unique to the Prius (and the Mercedes of post #41) that could obstruct the free flow of air while the car is parked? A cabin air filter.

 

Actually, this is supposed to be common industrial/commercial A/C cleaning. I'm still *very* surprised that this knowledge hasn't trickled down to the residential or automotive sector.

I've spent enough of my career dealing with balky chillers and recovery boilers - because naturally the plant manager will blame MY software for a mechanical problem so I'm still stuck fixing it! - that if I ever smell another stinky evaporator coil, I'll scream and jump out a window.

Ok, maybe not, but it bugs me that the auto sector can't design an HVAC case with easy access to the e-coil to at least properly clean it. The trucking industry appears to do so, a neighbor of mine near my hobby farm has a small fleet of Kenworth T2000 highway tractors, and the e-coil actually pulls *out* without disconnecting any tubing or discharging anything

I still am convinced the Prius A/C design is to blame, due to the very long cycle times of the compressor. Unlike a conventional A/C, engine driven and with an electric clutch, the Prius compressor is variable speed A/C.

The e-coil will remain cold and wet almost all the time while in operation. I have a similar problem with the Bryant Evolution system in my home and at my hobby farm: the variable speed furnace fan and 2-speed outdoor condenser are designed to run almost constantly.

I've done more research into this and apparently UV lamps in the duct plenum, directly over the e-coil, go a long way to keeping most of the mold/mildew under control. I've scheduled to have Bryant UV lamps installed at my hobby farm and my home.

For automotive applications, not sure if it's practical to put UV lamps into the plenum. Space is obviously pretty tight. I think we're stuck using the time consumming, messy, chemical sprays. I do know that NuCalgon EvapFresh and BioFresh absolutely work, and are safe for the e-coil

Oh, and my FJ Cruiser A/C is starting to smell now. Has been hot and muggy at the hobby farm, and about every 3-4 days I'll drive the 12 minutes to the nearest community for groceries and to visit folks. There is now a familiar odor.

The FJ plenum area is much different compared to the Prius. I think I can easily remove the blower assembly and blend door, and get access to the coil. Otherwise, through the firewall. I no longer recommend drilling into the case, unless you have access to a fiber optic inspection scope

I'll repeat again: never, *ever* use any sort of laundry bleach, even diluted, to clean an evaporator coil. The strong oxidiser will cause the aluminum fins and copper tubing to react