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Dangerous Recirculate Air Design Choice

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SaratogaSam

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Discussion starter · #1 ·
I am a relatively new owner of a 2023 RAV4 Prime SE. We took our first 1 hour+ trip on Sunday and after 1 1/2 hours in hybrid mode the air in the car was had an odor like the Canadian wildfire smoke, I then discovered that the Recirculate button was On. I was certain that I had turned Recirculate Off the last time I used the car, so I stopped and restarted the car. Sure enough, the Recirculate button came On. There was no odor in the fresh air, so the odor was coming from the car.

I checked the Owner's Manual and from that it seems as if the car is designed so that the Recirculate function will be activated each time the car is started, at least in the summer.

In my opinion, this is a dangerous design choice. No one should drive a gasoline powered car for extended periods of time with the air set to recirculate. So automatic Recirculate may be OK when in EV mode but definitely not in Hybrid mode.

is there any way I can change the behavior of the Recirculate button?
 
#2 ·
Initially the HVAC is in recirculate. When the car gets closer to the desired temperature, it seems to switch to flow through ventilation. I do not think you can change this operation other than overriding it each time you start the car.
 
#3 ·
SaratogaSam said:
I am a relatively new owner of a 2023 RAV4 Prime SE. We took our first 1 hour+ trip on Sunday and after 1 1/2 hours in hybrid mode the air in the car was had an odor like the Canadian wildfire smoke, I then discovered that the Recirculate button was On. I was certain that I had turned Recirculate Off the last time I used the car, so I stopped and restarted the car. Sure enough, the Recirculate button came On. There was no odor in the fresh air, so the odor was coming from the car.

I checked the Owner's Manual and from that it seems as if the car is designed so that the Recirculate function will be activated each time the car is started, at least in the summer.

In my opinion, this is a dangerous design choice. No one should drive a gasoline powered car for extended periods of time with the air set to recirculate. So automatic Recirculate may be OK when in EV mode but definitely not in Hybrid mode.

is there any way I can change the behavior of the Recirculate button?
Click to expand...
why do you think it's unsafe to run recirc? I run all of my cars in this mode in the summer because the AC works better under most conditions.
 
#5 ·
SaratogaSam said:
In my opinion, this is a dangerous design choice. No one should drive a gasoline powered car for extended periods of time with the air set to recirculate. So automatic Recirculate may be OK when in EV mode but definitely not in Hybrid mode.
Click to expand...
I laughed out loud reading this. Dangerous to recirculate the air by default? What is in the air that is so dangerous? The only time I've felt danger with recirc on was that time I tried a vegan burger and subsequently produced enough methane to power a small town. Now that's dangerous.

SaratogaSam said:
There was no odor in the fresh air, so the odor was coming from the car.
Click to expand...
"The call is coming from inside the house."
 
#6 ·
iTim314 said:
I laughed out loud reading this. Dangerous to recirculate the air by default? What is in the air that is so dangerous? The only time I've felt danger with recirc on was that time I tried a vegan burger and subsequently produced enough methane to power a small town. Now that's dangerous.
Click to expand...
I think he is concerned with CO poisoning.
Recirc is not 100% recirc for this reason. It blends in 5-10% fresh air.
 
#10 ·
SaratogaSam said:
When the gas engine is running, cutting off outside air increases the possibility that the air in the car will have high carbon monoxide levels.
Click to expand...
I'd agree if you're parked and sleeping overnight, but driving down the road?
 
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#12 · (Edited)
SaratogaSam said:
When the gas engine is running, cutting off outside air increases the possibility that the air in the car will have high carbon monoxide levels.
Click to expand...
I'd actually expect the opposite to be true unless you are driving and away from traffic. I usually can smell exhaust if I don't have recirc on and there is a lot of traffic.

with all of the wildfire smoke out there right now recirc is probably an even more clear choice.

doing some googling I guess there is some concern where a lot of people in the car at once could cause a build up of CO2 but I question if the the overall system is airtight enough for that to be a concern. I've never noticed any ill effects driving 3-4 hours with my whole family in the rav4 or my past cars in the summer with recirc on the whole time.
 
#13 ·
SaratogaSam said:
When the gas engine is running, cutting off outside air increases the possibility that the air in the car will have high carbon monoxide levels.
Click to expand...
Never heard of this. I've been driving for 40 years and have always used the recirc mode and that includes several 6000 mile road trips in the middle of summer driving through areas like Texas, Utah, Arizona, New Mexico, Nevada, etc. During all that driving with recirc mode on I've only died once from carbon monoxide poisoning.

I remember even when I was a kid my grandparents always drove with recirc mode on. My grandmother died at age 90. Poor soul... I guess it finally caught up to her.

🙂
 
#14 ·
CoffeeBear said:
why do you think it's unsafe to run recirc? I run all of my cars in this mode in the summer because the AC works better under most conditions.
Click to expand...
Not a good idea to be recirculated/breathing toxic fumes when the car has been sitting or driving in the hot sun for hours. The plastics, seats, carpet, etc surely give off plenty of toxic fumes - especially when vehicle is new. I turn recic off always. Very annoying to have to do this every time. Never had to do this repeatedly with other vehicles.
 
#16 ·
peakbagger said:
BTW modern I/c engines with high efficiency catalysts put out little or no carbon monoxide.
Click to expand...
it doesn't matter what is in the exhaust, what isn't in there is breathable oxygen.
also, almost every car has some type of exhaust leakage at some stage of
it's life. you never want to breathe any of that

anyhow, there is no danger running recirc all the time in ordinary circumstances.
the danger is running a vehicle long term when stopped where efficiency is lowest and
exhaust contains the most CO (such as camping in vehicle), or zero outside air movement, or
stuck in a snowbank, or in an enclosed space
 
#18 ·
Northstat said:
Not a good idea to be recirculated/breathing toxic fumes when the car has been sitting or driving in the hot sun for hours. The plastics, seats, carpet, etc surely give off plenty of toxic fumes - especially when vehicle is new. I turn recic off always. Very annoying to have to do this every time. Never had to do this repeatedly with other vehicles.
Click to expand...
typically I'm starting my car up after it's been in the garage. if it's been in the hot sun I'm opening the windows at first just to let out the super hot air that's inside.
 
Discussion starter · #19 ·
SaratogaSam said:
Thanks. I will try that.
Click to expand...
jazhanel said:
Turn off Auto mode, and turn off recirc, it will never come back. Your mileage will suffer.
Click to expand...
The service department at my Toyota dealer gave me the same advice. However, when I tested that method by turning Auto Mode Off, Recirculate still came back on when I started the car, which is consistent with the user manual. So, if I want fresh air in the summer, I'll just have to remember to turn Recirculate off each time I start the car.

BTW - my previous car was a 2012 Outback. That car would turn on Recirculate only if the A/C was set to Max Cooling and would turn it Off for all other settings. I agree with the other posters that it is unlikely to pick up CO when the car is moving, but there was definitely a strange odor in the car last Sunday after 1 1/2 hours of driving with Recirculate On.
 
#20 ·
SaratogaSam said:
The service department at my Toyota dealer gave me the same advice. However, when I tested that method by turning Auto Mode Off, Recirculate still came back on when I started the car, which is consistent with the user manual. So, if I want fresh air in the summer, I'll just have to remember to turn Recirculate off each time I start the car.

BTW - my previous car was a 2012 Outback. That car would turn on Recirculate only if the A/C was set to Max Cooling and would turn it Off for all other settings. I agree with the other posters that it is unlikely to pick up CO when the car is moving, but there was definitely a strange odor in the car last Sunday after 1 1/2 hours of driving with Recirculate On.
Click to expand...
I don't think that strange odor had anything to do with recirc mode. On some of my cross-country drives in hot weather I did often notice a strange odor after a few hours of driving with recirc on but it turned out to be the odor of feet.... so there's that.
 
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