Replacing the AC EVAPORATOR? Mold / Smell in the AC System

Recovering the refrigerant (R-134a, not Freon 12, by the way) is the easy part. The evaporator is part of the air conditioning unit assembly, and as the Repair Manual (more info) explains, to get to it, you have to take apart the entire instrument panel. Toyota’s Flat Rate Manual allows 6.1 labor hours for removal and replacement.

Toyota’s service bulletin, T-SB-0143-13, “HVAC Odor Maintenance” (PDF), revised November 10, 2016, has some suggestions, besides their cleaning kit. You could try to make a habit of switching to the fresh air mode when parking, and replace the cabin air filter with a charcoal-impregnated one, part number 87139-50100.

Perhaps @lech auto air conditionin would be kind enough to share some suggestions, too.

 

One way we cleaned the evaporator in Mercedes was to close the windows, put the a/c on recirculate,
fan on high and spray a full can of lysol into the air intake inside the car then let the car run about 10 minutes.
Make sure to hold your breath when spraying!

 

Are you sure you’re smelling the evaporator? Could be the carpet, pond in the 12v battery well, spare tire well etc…

Replacing the evaporator is ridiculously labor-intensive on most cars, the Prius is no exception.

 

Well, that's why it's to be recovered using suitable equipment. If you don't want to buy expensive equipment for one job, well, that's kind of a thing A/C shops do.

You could have a shop evacuate the system for you, drive it home, do the hours and hours of instrument panel R&R yourself, and go back to the shop when you're done for evacuation and recharge. I went that route with another vehicle, it was pretty painless.

You don't have to, and, seriously, don't.

Old Ford Ranger / Bronco II for the win. HVAC case was two shells, one either side of the firewall. Evaporator in the engine compartment side. If you had a helper, you could unbolt the compressor, condenser, and evaporator, and lift the whole A/C right out of the truck unopened (I was doing an engine rebuild) and put it right back in afterward.

Had to first push the engine wire harness grommet through the firewall (the wiring went 'through' the loop of A/C hoses) but that was about the only prep needed.

 

I never dealt with one of those, but a lot of them were easier in the days when AC was still available as a dealer-installed option.

 

Eh, just throw yourself down a flight of stairs and it’ll be less painful than getting useful Prius info from Chilton’s.

The real stuff is on Toyota’s tech info website. Not free, but cheap enough and the manual available there is fantastic. You can use your access to save portions of it for later reference.

 

The Chilton books may be too thin to be useful, but the ChiltonLibrary online database (mentioned on the PriusChat Wiki page) includes the text and illustrations from Toyota’s Repair Manual for the 2012 Prius, plus most of the pages from the Electrical Wiring Diagram. The formatting and organization could be better, but if your local public library subscribes, it’s a no-cost option.

 

you can attempt to try some of the cheaper alternatives using sprays is the easiest do it yourself method. sometimes it works for months occasionally it works for years. but that also depends where you live and what kind of mold spores are in the air what kind of plant material is in the air , dead leaves and grass.
Different parts of the Country and different automotive distributors carry different products.
You are definitely looking for one that specifically says it’s a anti-bacteria or anti-fungicide. Some of the kits even give you a second aerosol spray canister that is nothing more than a perfume to cover up the smell I personally and many other people cannot stand the overbearing strong smell of some of these fragrances.
You must read all the instructions entirely for it to work effectively. The majority of the products want to be sprayed on a dry evaporator so that means your air conditioning must have not been in use recently to condensate water on the fins and coil. By opening up your glove box and removing the air filter turn on your fan in spray on the inlet of the fan keep your face out of line of sight of where the air is discharging out of the ducts.
Some instructions will tell you to keep the fans running either instructions may tell you to turn the fans off. Then the instructions will give you some sort of set time to wait to allow the chemical to dry into a film that stays attached Coating in the fins. In the meantime do not turn on your air conditioning or defogger. Because this will cause your evaporator to get cold and instantly start making water that will wash off the chemical.

And be careful some of the recommendations of home do it yourself products are corrosive on aluminum with the additives in some of the homebrewed bathroom type aerosols. It will not do immediate damage it’s something that happens over a long period of time and replacing a leaky evaporator on a Prius is not a cheap job.

I also forgot to mention in some cases depending what your contaminant is dust or spores from trees use one of those expensive really tightly pleaded dense filters to reduce the amount of small particulate matter the only problem with those fine filters they plug up really fast and start restricting airflow. Depending on how dusty your environment is I would recommend pulling it once a month and blowing it out with Shop air in reverse airflow order so it does not create a restriction any little restriction of airflow reduces cooling performance.

 

The only problem with spraying a mist of oil bearing products oil stay sticky and tacky and collect dust that will build up and restrict airflow in between the fins.
Fine particles of dust love collecting and sticking to oil it acts like a filter.
Oil work so good as a filter back in the old days on cars before they had mechanical paper element filters they had something called an oil bath where your air filter was nothing but a channel that air ran down through a groove to a large puddle of oil in the bottom of the air filter channel and then back up before entering the engine.

 

If the man wants to remove or disassemble the whole car to clean the evaporator, let him do it.
It's his car. Perhaps he likes doing things the hard way.

Several people have given him very good ways of cleaning it.
Let him decide on how he wants to do it.

 

And additional food for thought:
The smell can be caused by "stuff" growing in the drain pan due to poor drainage.
It also can be due to "stuff" building up in the air intake, usually between the back of the hood and the bottom of the windshield.
You should check those two things first.
A really competent A/C place would tell you that.......or offer to do it for you for a few $$$.

 

You're telling the wrong person.... I already know this.....
My a/c doesn't smell...

 

My comments really weren't directed at YOU.
Did you really NOT understand that ??

 

The Achilles heel of most-if-not-all AC systems, is if you use them constantly, right up to the point you shut the car down, you've created an ideal environment for mold to grow. A couple of mitigating tactics:

1. Just don't use the AC so much. Run the fan without AC, and/or crack the window down a bit and shut it right off.
2. When you do use AC, try to remember to shut it off at least a mile before your destination, and keep the fan running at moderate speed, to blow out the humidity.

 

One more thought:
If.....you car sits in a garage or under a roof most of the time, that is the ideal environment for mold growth in the summer.
Mold doesn't like REALLY hot nor really cold.

One of the "spray can" treatments sometimes works a lot better if you combine it with sitting out in the bright sun for a day or two......in the summer, that is. When you first notice it, running the heater for a bit can help too.

 

A coarse filter on the air intake under the hood will help after you get things clean (will also keep mice out).

I second the idea that tea tree oil will eventually do more harm than good. Since you don't want to use sprays, I'm going to recommend the periodic use of an ozone generator. It's frequently used on boats to reduce/eliminate mildew, and works really well in enclosed spaces. Do not EVER use it while you are in the car, and let the ozone dissipate before you get in it again.

Use it overnight, or even better, over 24 hours or more.