danynijm

Hot air blows out from vents unless I turn the AC on. There are times that the top is down or the temperature outside does not require the AC but with the hot air coming from the vents, you have no choice.

I had the same issue with my 1997 SC400. Does anyone know how to stop the hot air from blowing? I did close the vents but it still manages to come out from other vents such as the defroster.

Thanks!!

1NICESC430

Check under the hood ... one of my senators might be there.

advancer

Danynjim: Funny you should post that. I noticed the same thing just tonight while driving with the top down. It seems to happen even with the climate control off. I was going to check the manual. Its very annoying and I figured I just have something set improperly

fletch

Check the temperature setting on the climate control. Even when the climate system and fan are off, I found that if the temp was set high, hot air escapes the vents when the car is in motion. I know it seems counter intuitive since this is a sophisticated digitally controlled system. But the hot air is gone...

El Jefe

The Sentator line was priceless.

I recall my dealer telling me someting about the car automatically forcing air through the lower vents at a relatively "high" fan level whenever the top is down....what I was told is that this helps control the temperature of the cabin given the aerodynamics when the top is lowered. Don't know if that was BS or not, but it's consistent with what's been posted above and makes sense that it can be adjusted via the climate control temp setting even when turned off.

danynijm

I tried lowering the temperature all the way to 65 and still the hot air comes out. Please let me know if you have any other ideas.

1NICESC430

danynjim ...

I haven't tested this phenomenon yet on my SC, but I do remember having a similar problem with another car (can't recall which one). The service people told me that the air coming in from the outside will naturally heat up because of the warmth of the areas within the engine compartment that it passes through before it gets to the cabin.

I suppose if the outside air is very cool, it might not transfer as much to the warm engine compartment, but if the temperatures are close it might heat up a bit.

I don't vouch for this explanation and it may be hogwash - just passing along what I was told.

mahroni

i have this same problem on my 04 sc430. It almost seams like hot air is coming from behind or inbetween the radio... I am planning on taking it to the dealer to see if they can figure this out.

dsimo

I've noticed the warm air as well. I attribute it to the heat coming off a V-8 engine sitting a few feet away, warming the air as it runs through the vent ducts. If there's another reason, I'd sure be interested to know.

HotBlue400

first thing to check, make sure that the air circulation button is on re-circulate, not taking air in from outside,.. that always helps.

JCtx

Few pointers:

-if you want fan OFF and no outside air, press the 'RECIRC' button until ON. No need to turn individual vents off; this will cut all air from outside when system if off.

-System temp stays ACTIVATED even when OFF (and 'RECIRC' OFF). That means if you have it at 85, it'll blow hot air regardless if winter or summer.

-NO front-engined car is going to blow air at the outside temperature; not even close. This has been the case with ALL my cars, so if air blows cold with A/C on, all is well. And yes, it has to do with engine compartment temperature.

-When it's cool outside and the engine is hot, try briefly turning the A/C on until air is cold, then turn it off (and set temp to lowest), and incoming air will be much cooler than before, but don't expect it to match outside temperature.

Cheers.

GGMCGG

I have been waiting two years for someone to address this hot air issue with the SC 430. I owned a 2002 model for a very uncomfortable four months.I noticed shortly after buying the car that hot air would be drawn from under the dash when the top was down ( due to convection currents?). After I proved this problem to the dealer they tried to fix the problem to no avail. So the I purchased a digital thermometer and suspended the remote probe close to the pedals; the readings averaged around 118 degrees. With this evidence I presented my case again. A week later Lexus flew two engineers from California to Florida to work on my car. They worked on it for two days. They traced the problem to the constantly charged heater exchange core that resides in the passenger compartment ,which they attempted to insulate better. Their repair dropped the temperature to a cool 110 degrees. At this point I had a tough decision keep the car and run the air conditioner all the time or get rid of the car. I couldn't accept the fact that a $62,000 car would have such a design flaw so I worked out a deal with the Lexus Corporation to take back my car. In retrospect I do miss the car but having a virtual hot foot every time I drove it was seriously diminishing any enjoyment I derived from the vehicle. Good Luck..........

1NICESC430

Oh boy ... I get a chance to use my digital thermometer with remote probe for something other than meat (sorry, PETA). While I have never experienced GG's problem, I'm going to check the temp down there anyway.

JCtx

I'm happy to say I don't have the problem on my '04. At least that's what my 'human' thermometer says; I drive without shoes

1NICESC430

Well, I pulled my remote temp probe out of the meatloaf, hung it between the brake and accelerator, put the top down, and went for a highway, byway, and in-town drive to do some errands. The outside temp was 75 and the probe temp never got above 80.

I left the car in the sun for about 45 minutes with the top up; the probe temp was 93 when I returned. I put the top down and got on a soon-to-be interstate highway driving about 65-75mph. The probe temp got up to 100, so I opened the outside vent and set the mode to "Feet" just to see what would happen. The temp dropped a little, but stayed in the 90s for the entire 25-minute trip back.