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08 Highlander AWD (Serious Wind Noise When Rear Window Down)

20 messages,  Last post on Apr 20, 2009 at 4:52 PM

You are in the Toyota Highlander Forum.

What is this discussion about? Toyota Highlander, Car Buying, SUV

Messages Page 3 of 3

#12 of 20 Re: [wlbrown9] by wwest

Dec 19, 2008 (6:54 pm)

Replying to: wlbrown9 (Dec 19, 2008 11:43 am)
Sorry, I was thinking Rh and should have said so.
 
In yesteryear the use of the A/C as an aid to defogging, ONLY as an AID, automatically coming on in defrost/defog/demist mode was a quite reasonable action.
 
Not today, no more.
 
Think about what might happen, often does happen, once you leave defrost/defog/demist mode...
 
The interior windshield surface fogs over again, even quicker this time.
 
When you switch off defrost/defog/demist the moisture just previously condensed on the evaporator vanes will soon begin to evaporate into the incoming airstream, DRY incoming airstream in COLD climates. Therefore the incoming airstream will more quickly "absorb", SUCK UP", the evaporator condensate.
 
The proper way, the only reliable method, for defogging the interior surface of the windshield is to HEAT the airflow flowing toward the interior windshield surface. That accomplishes multiple positive aspects things, heating the airflow will LOWER its RH, and then transferring some of that heat to the interior windshield surface will result in quicker evaporation of teh condensate and also help to prevent windshield fogging/misting.
 
My new 1992 LS400 was so bad, horrible, really, at sudden instances of windshield fogging that I was forced to park it for two winters in a row until I could figure out the problem and thereby arrive at a fix.
 
In the end I realized that I had to disconnect the A/C compressor clutch during the time period wherein I did not need cooling. I also built in a circuit and switch to cause the climate control system to "think" the cabin had suddenly gotten VERY cold. If the windshield started to fog over I would first activate the new switch and then activate the defrost/defog/demist mode. The system would then automatically go into MAX heat and max blower speed.
 
With my '01 F/AWD RX300 came two new C-BEST features/options. I had the dealer set these options so I could disable the A/C indefinitely by simply switching it off once, the second option involved unlinking the A/C from automatic operation in defrost/defog/demist mode.
 
With the RX's controls a quick clockwise twist of the temperature setpoint knob gets the system to max heat (by default, max blower) in preparation for subsequent, immediate, activation of the defrost/defog/demist mode.
 
On the '92 LS400 I added two 12 volt fans, one in each rear quarter panel, that automatically come on in defrost/defog/demist mode, and with rear window defrost activation, to help remove the rise in cabin humidity that results from teh aforementioned actions.
 
A bit of overkill, that, all one really need do is train yourself to ALWAYS slightly lower a rear window temporarily when using either function, front or rear "defrost".

#13 of 20 Re: [kenlw] by wwest

Dec 19, 2008 (7:11 pm)

Replying to: kenlw (Dec 19, 2008 12:23 pm)
".. Dehumidification is THE SINGLE MOST important feature of AC.."
 
That statement leaves me so FLABBERGASTED that I don't know what to say in response,.. almost.
 
Let's totally disregard what I might wish say in response since that would surely get deleted.
 
So.
 
I am given to understand that we humans are most comfortable at an Rh of ~40% provided the surrounding air temperature and radiant "inputs" are also within our human comfort zone.
 
I think you might agree therefore that dehumidification of a building's airflow might be at times, a highly undesirable "feature" of A/C operation. And what happens in say, Az when the Rh is sometimes, or maybe even predominantly, <10% Enough said...I will render no further response to kenlw.

#14 of 20 by kenlw

Dec 20, 2008 (6:44 pm)

that's good because my sides hurt from laughing at your illogic.

#15 of 20 Re: [wwest] by mdhutton

Dec 21, 2008 (10:26 pm)

Replying to: wwest (Dec 19, 2008 7:11 pm)
Believe what you want to belive, wwest. Let me know how that ice scraper works on the inside of your windows sometime.

#16 of 20 Re: Buffetting noise - wwest's fix [wwest] by houston_man

Apr 18, 2009 (7:27 am)

Replying to: wwest (Dec 17, 2008 1:06 pm)
Regarding these outlet airflow vents, can you describe in detail (or provide a picture) of how/where you mounted them and the part number? Reason I ask is that I am also trying to alleviate that noise in our Highlander.
 
Thanks....

#17 of 20 Re: [mdhutton] by wwest

Apr 20, 2009 (10:26 am)

Replying to: mdhutton (Dec 21, 2008 10:26 pm)
In my travels worldwide, including especially Fairbanks, Anchorage, Point Barrow, and Goose Bay, I have NEVER encountered ice on the inside of my car windows.

#18 of 20 Re: Buffetting noise - wwest's fix [houston_man] by wwest

Apr 20, 2009 (10:30 am)

Replying to: houston_man (Apr 18, 2009 7:27 am)
Toyota P/N is 62905-60050, louver, sub-assy. Mounted just below and at the rear of the rear quarter panel window that unlike most minivans will not open to alleviate this COMMON problem.

#19 of 20 Re: [wwest] by steve_ HOST

Apr 20, 2009 (1:48 pm)

Replying to: wwest (Apr 20, 2009 10:26 am)
Happened all the time on my late 60's Super Beetle in Anchorage. My girlfriend (now wife) made me trade it in fact - she got tired of scraping the inside of the window. Pitiful heater. Maybe there was moisture in there somewhere, but it sure iced up.
 
I've been to all those spots too. Was that you who cut me off in Happy Valley (or was it by the ACC store?).

#20 of 20 Re: [steve_] by wwest

Apr 20, 2009 (4:52 pm)

Replying to: steve_ (Apr 20, 2009 1:48 pm)
Oh...... I see...
 
That's the reason my '78 Porsche Targa doesn't get to go out much to "play" in the winter snows. Saying it has a cabin heater is a bit of a stretch to begin with and then having the expectation that you have enough heat to keep the windshield interior clear of condensation coming back over the Snoqualmie pass on a dark, cold, snowy night, well....
 
Having to roll the windows down in a pretty severe snowstorm in order to keep the winshield defogged was not pleasing to my better half. Never happened again.
 
Of course the TENSION involved in driving a rear engine rear drive car in those conditions probably contributed greatly to the level of moisture being accumulated in the cabin.

Messages Page 3 of 3

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