Heat Coming From Vents

[Rx330driver]

i just have a question about cars in general, but its almost worse in my RX. for some reason, in these past few weeks, hot air has been constantly coming through the vents without the aircondition on but with the recirculation off. so i know air should be coming in fron the outside, but why is it hot? its not particularly warm in san francisco either. everyone who gets into my car says its stuffy.

[amf1932]

The reason you're getting hot air out of the vents is because of the heat from the engine compartment. This is normal. If you try turning down the temperature control with the compressor turned on to cool the air, then turning off the climate control system, and have the recirculation off that might help. Actually, the climate control was designed to work with the heater and cooling unit operating together, and constantly modifying the cabin temperature. Nothing to worry about though. :)

[Rx330driver]

err, yeah thats what i thought. but after at least 30 minutes of driving in town, it was still blowing warm air in. i also tried the aircon trick, which was originally set at 71, which isnt that warm. it seems to be staying at the warm temperature.

[amf1932]

Then try setting your temperature control to the 'coldest' and then leave the complete system off and out of recirculation. Use the fan to move the hot air out of the ducts.

[Rx330driver]

will try that, but im telling you, this has just been happening, even after driving for a long while. before this happened, i get the green light off so that air would come in and so i wouldnt have to use the aircon nor open a window.

[wwest]

will try that, but im telling you, this has just been happening, even after driving for a long while. before this happened, i get the green light off so that air would come in and so i wouldnt have to use the aircon nor open a window.

My 92 Lexus LS400 has a hot water shutoff valve within the engine compartment, top-center of the firewall, that is completely closed when the system calls for max cooling. The valve is operated by a push/pull cable that comes through the firewall and is actuated by the same servomotor that operates the blend/remix door/vane.

I noticed that in my 2001 AWD RX300 that valve is eliminated and so hot water always flows through the heat exchanger within the A/C plenum. So even with the blend door fully closed airflow coming to you via the climate control system (Max cool, A/C off, blower off, fresh inlet airflow) might be slightly elevated above OAT ambient. With the system set in anything other than max cool (max cool forces the blend/remix door/vane fully closed) the system outlet airflow might become significantly hotter that outside ambient.

Your only other option is to go to Home Depot and buy a manual water shutoff valve to install in the hot water hose, the one with flow toward the heat exchanger, within the engine compartment.

[SW03ES]

I leave mine in AUTO mode and am always comfortable...