Works great doesn't it. You can also use the same process on window units or central air units if there is a build up of mildew / mold. Heck of a lock cheaper then the Toyota can.

What about using a bottle of febreze after the alcohol using the same method? Anything harmful to the car in the febreze?

Yes! My local Toyo stealership wanted to pump a "chlorine bomb" up the ac drain hose as a starting point. I can see the sense in that but if the mould has already taken hold on the evaporator and the ducts... not sure what the long term effect would be.

Likely they would have conned me into a full ac system service and refresh. $250+ later they'd say, we solved your problem.

btw My mom who has a chronic condition uses 70% isopropyl to disinfect her medical supplies. She swears by the stuff. Evaporates quickly and prevents the spread of infectious stuff which her body can't handle.

I want to do this but on all other videos I watched where people were using Lysol they had the AC switched on. You said to switch it off. Just wanted to make sure if it should be switched in or off?
Also how much roughly is a good amount, 500ml?

Thanks

For future readers like me who are looking for solutions:

The auto-ignition temperature of 70% isopropyl alcohol is 750.2°F, but, this is the temp that it will ignite without a spark. This means that if you heat it above 750.2°F, it will ignite on its own, no spark needed.


The flash point, is between 53 and 55°F. If there is a spark or ignition source, it will ignite at this temp. There’s a reason they put FLAMMABLE on the bottles. If the it were 750°F, it probably wouldn’t be considered flammable.

I’m not sure there’s an ignition source in the AC system where the alcohol would go, but still, it makes it sound like there’s no concern at all for it to ignite.

i've really gotta give this a try! so, no need to remove cabin air filter?

I did this many years ago with 70% isopropyl and my AC system has been clean and smell-free since. Remove your cabin air filter first because (1) leaving a filter in place will stop most of the alcohol from going into the parts of your system that need disinfecting, and you'll end up with a soggy filter, and (2) you will install a new cabin air filter after this procedure anyway.

Fill a 500mL to 1L spray bottle with 70%-80% isopropyl (I buy bottles of 99% from Costco and mix down to use as an all-purpose cleaner and disinfectant), where the spray nozzle can be set to a fine mist instead of a squirt, and mist the entire bottle into the fresh air intake, which is a port in the plastic windshield wiper grille on the passenger side. With your fan on max, you can easily feel where the air is being sucked in, and that's where you mist the alcohol.

I believe I did this with the engine off and windows down, but it was so many years ago, I'm not 100% sure. I'm thinking that if you turn the engine and AC on, there will be too much water condensate on the condenser, which will water down the disinfecting power of your incoming isopropyl mist. Definitely don't turn the heat on, because your alcohol will evaporate too fast. 70% alcohol needs at least 60 seconds of contact time to disinfect a surface (higher % alcohol evaporates too fast before disinfection can be completed).

I even went to a local Dodge dealership and bought one of those foaming AC disinfectant cans with an adapter to spray UP the condensate drain pipe under the car, but after doing this 70% isopropyl disinfection, I never had to use this AC cleaning spray can and still have it.