Rx400h A/c "inside Air" Vs "outside Air" Setting

cduluk · December 9, 2009

Hey guys.

On the Rx400h air conditioning unit, there's a button that allows the user to select between "inside circulation" (which is supposed to just re-circulate the inside air) or "outside circulation" (which allows air from outside of the car to be circulated into the car).

I like to keep the setting to "inside circulation" only because i can't stand the outside smells such as car fumes, diesel smell, and for anyone who's familiar with route 295 going through Rhode Island, the Johnston Land Fill...

But it seems that even with the setting set to "inside circulation" i am still getting outside smells. Not as badly as when i have it set to "outside air", but maybe only 50% better- which is not good enough IMO.

In my old Rx300, if you had it set to "inside circulation", NO smells ever entered the car. It was air tight.

Is anyone else in the Rx400h (or maybe the Rx330/350) noticing the same thing?

When i press and depress the button that toggles between the settings, i can hear "things moving" in the dash, and i can feel the difference in air between the settings- but the smells are still getting in.

I replaced the cabin air filter, so it's not that.

My next step is to find the air intake spot on the Rx400h, and see if it's sucking in outside air even if the setting is set to "inside circ"...

I know in the Rx300, the outside air intake was located in the left rear bumper area, not sure where it is on the Rx400h.

Could it be that the "lever" or whatever mechanical device that controls the passage of air in the dash is maybe not closing all the way?

Any input appreciated! :)

skyfish400h · December 11, 2009

I like to keep the setting to "inside circulation" only because i can't stand the outside smells...
...even with the setting set to "inside circulation" i am still getting outside smells....

Is anyone else in the Rx400h (or maybe the Rx330/350) noticing the same thing?

I LIVED on outside for the first year I owned the RX and would only switch to inside when I anticpated a bad smell coming (behind a desiel, etc). But this makes you run thru cabin filters like they are going out of style.

Now I just leave on inside (RECIRCULATE) all the time and just open the windows when I want to breathe fresh air. Since I've made the switch I've never encounterd outside smells no matter what the situation.

I do sometimes get the filter smell (smells like socks) when the system first fires up after sitting, but I can quickly purge that by cracking the rear windows an inch or less. When it starts to smell like really OLD socks, I know it's time to change the filter ;)

lemon · December 12, 2009

Can't do that if you live where it's cold, or you will fog up all the interior windows.

cduluk · December 12, 2009

Can't do that if you live where it's cold, or you will fog up all the interior windows.

Oh yeah, i do notice it fogs up the inside when running inside air, but for the most part i've been OK.

So what do you guys think my next step should be to test if there's indeed an issue with my unit?

pauljcl · December 12, 2009

Can't do that if you live where it's cold, or you will fog up all the interior windows.

Oh yeah, i do notice it fogs up the inside when running inside air, but for the most part i've been OK.

So what do you guys think my next step should be to test if there's indeed an issue with my unit?

Isn't there a time limit on the fully 'closed' circuit of re-circulation? There was on my MB about 20 years ago, so as to prevent the air from becoming so stale (CO2) that driver might nod off. Maybe the circuit does let in a little outside air on purpose. Why not call a dealer and find out what it is supposed to do?