Deep cleaning Gen 2 air ducts

Look up the A/C evaporator replacement procedure in the service manual. You have to remove the entire dashboard. That will let you remove the air ducts. To get inside the HVAC case and clean the evaporator and heater cores, you need to recover the refrigerant charge, drain the cooling system, remove and disassemble the case.

When you're done, put it all back together (might as well install a new evaporator core at that point), evacuate the A/C system. Then add the correct weight of 134a refrigerant and some of the correct oil.

Probably something around 10 hours of labor for the core. Cleaning things takes longer.

This is a Gen2 I did the core on a while back. It would have been some easier if I had lowered or removed the steering column.

Posted via the PriusChat mobile app.

 

I avoid mold in the AC evaporator coil by always turning off the AC compressor a couple of minutes before arrival. This dries off the coil and prevents the development of mold.

JeffD

 

Maybe flush the drain line from the evaporator, which runs under the front passenger side carpet. Apparently it can get stuff stuck in it and that would tend to promote mold growth.

 

^This. And more like "a couple of miles", minimum. Ensure the fan is running on moderate/high speed too.

Too, reduce your use of AC: on temperate days, and/or short trips where AC will barely have time to stablize. Roll down the windows, lol.

The mold issue pretty much never happened prior to the adoption of automotive AC.

 

Found this thread while searching. Just want to say that I found the YouTube video where somebody points out the best spot to drill a hole to get into the evaporator with a probe. I did get in there with my probe (drill a hole just below and this side of the lobe that sticks out under the foot well driver side of the plastic casing) and saw that it looked kind of nasty, but even after I steamed and sprayed the hell out of it in there, I get a cigarette smell from the heater enough to give me an asthma attack .

 

I’m probably going to get rid of the Prius rather than disassemble the dash. But I might take a picture of the hole drilled and what it looks like inside for the benefit of everybody else.

I suspect I was not able to get to the nastiness that must be caked on the heater core and hvac ducting

 

Toyota sells a foaming cleaner for the evaporator. It goes up the condensate drain hose as foam, does its scrubbing bubbles thing, then all the bubbles burst and it runs back out through the same hose. I don't recall other details, but it is what the manufacturer recommends for cleaning that part.

As far as cleaning the ducts, well, if somebody smoked in it it will take a long time to get rid of the smell, since the tars and such stick to the plastic walls and take a very long time to evaporate off. It could be that a substantial fraction of the cigarette smell when the heater is on is actually coming from surfaces which are not in the dash. My son briefly had a Tacoma that had been smoked in, and most of the smell came off by in about two months by repeatedly cleaning all the exposed surfaces and letting the truck bake in the hot LA sun. He never did anything to the vents.