Last post on Sep 22, 2013 at 3:56 PM
You are in the Lexus RX 300/330/350
What is this discussion about?
Lexus RX 350
#194 of 522 Re: air conditioner smell [tjinla]
Nov 15, 2006 (4:04 pm)
Yes, there is "something" inherently wrong...!!
The first thing WRONG is that these climate control system are designed by NipponDenso, ne Denso US. These designs are inherently flawed in too many ways to quickly list.
First, go to Lexus and have them set a few of the c-best options to other than the factory's (stupid Denso engineer's) default position.
1. Set the C-best option that will give you the ability to indefinitely disable the A/C compressor's operation by simply turning it off one time. The A/C will not be enabled again, through multiple restarts, until you turn it back on manually.
2. Set the c-best option that "unlinks" the A/C from operating automatically, with no indication, no indicator lit, in 3D mode, Defrost/Defog/Demist.
For many years I always disconnected my A/C compressor clutch connection during the winter months. The possibility of the A/C being efficient in dehumidifying the incoming airflow during the winter months is a TOTAL wildcard. Actually WORSE that that, you're more likely to draw aces and eights than any safe hand.
3. It is my understanding that as of more recent times, RX350, there is yet another c-best option that will help out. Apparently there is now a c-best option that can be set to prevent the system from automatically switching from heating mode (primarily footwell outflow with a goodly level of "leakage" of airflow to the windshield to help keep its interior surface above dewpoint), into cooling mode, cool and dry airflow to the face and upper body and NO warming airflow to the windshield, DANGEROUS, in a cool or cold climate, that!
My most recent test drive of a new RX seemed to indicate that even more progress has been made. Unless I miss my guess it appeared to me that while the airflow temperature was not raised significantly the blower speed was raised when I switched into 3D mode after the system had automatically switched to cooling mode on a rather COLD day.
1989: "The Relentless Pursuit of Perfection."
1999: "The Passionate Pursuit of Perfection."
Soon after purchasing my new 1992 LS400 I learned that the best way to prevent the dirty gym socks odor from the A/C was to roll the windows down slightly each and every night as it sat in the garage.
Over a period of time I made several modifications to the 92 LS that helped to prevent the odor problem, the propensity for the windshield to fog over suddenly, and increase, dramatically, the ability to more quickly defog/demist the interior surface of the windshield.
The A/C in the 92 LS400 is disabled if the OAT declines below ~35F. I modified the OAT sensor such that at ~45F actual temperature its signal indicated to the climate control ECU that it was nearly freezing outside. MY 1992 LS400 therefore NEVER runs the A/C if the outside temperature is predominantly 45F or below.
Since the stupid Denso engineers decided to use, EXCLUSIVELY, (??!!) the dehumidification capability of the A/C to prevent, or even remove, windshield fogging, and since having that capability was therefore an absolute wildcard, I had to come up with a more reliable method of accomplishing this.
So I added a "hidden" switch that when flipped "on" adds a resistance, ~300 ohms, in series with the IAT sensor. If I notice that the windshield is beginning to fog over I first flip the switch and then activate the 3D mode. The additional resistance in the IAT circuit makes the climate control ECU "think" the passenger cabin has suddenly gotten colder and so it reverts to a SERIOUS level of heating, while simultaneously increasing the blower speed.
Apparently the climate control firmware in my 2001 AWD does not allow (presumably some digital signal processing was added) "sudden" changes in the IAT sensor output. Additionally, modifying the OAT signal to prevent A/C operation during predominantly cool/cold weather also resulted in an incorrect OAT readout on the Nav display.
So I have had to resort to other methods, modifications.
There is now an additional microprocessor in my 2001 AWD RX300's climate control system. When I switch to 3D mode the up/down temperature set signals are "intercepted". When the new microprocessor "sees" that the system has been put in 3D mode it automatically raises the temperature setpoint to MAX HEAT. That, of course, results in the blower speed quickly going to maximum speed.
So when, anytime, I put the system in 3D mode I virtually instantly get lots, TONS, of heated airflow to the interior surface of the windshield.
Discomforting, yes, in spades, but much better then the alternative, possibly leading to an early grave, provided by Denso. Now I have the ability, once the windshield is mostly or completely defogged, to modulate the temperature setpoint while remaining in 3D mode.
Once I return the system to normal mode the new microprocessor will return the setpoint to the temperature it was just before activating 3D mode.
Go to airsept.com and read up on their EED, Electronic Evaporator Dryer. Many Ford dealers, due to A/C odor complaints such as yours, will modify, with Ford's blessing and expense, the A/C system using this same EED.
#195 of 522 Re: air conditioner smell [tjinla]
Nov 15, 2006 (9:57 pm)
Tjinla, I've only experienced that unpleasant
smell once in my RX350, and I've had the car
since August. I was on vacation in the mountains at the end of October and I believe
I was trying to "defog" the windows when I got
a whiff of that nasty smell.
#196 of 522 Re: Air Conditioner Odor Suggestion [pschiffe]
Nov 15, 2006 (11:37 pm)
Had the filter changed on the last RX and that lasted for a couple of weeks before it started smelling again.
#197 of 522 Re: Air Conditioner Odor Suggestion [tjinla]
Nov 16, 2006 (12:52 pm)
I think I saw somewhere that the newer LS series has a UV light within the A/C plenum area to "kill-off" the microbes that cause the mold and mildew odor due to the "leavings".
I have a 12 volt version, UV light source and air circulation fan, in our MH for the same reason. About the size of two cigarette packs end to end.
Seems to work.
#198 of 522 This is copy of email sent to Steve.
Nov 19, 2006 (10:55 pm)
THIS IS COPY OF EMAIL I SENT TO STEVE. I AM POSTING HERE SO THAT MORE PEOPLE COULD READ IT. THANKS!
Hello Steve - I'm kind of new to this forum stuff but I really desperately need some help. I originally posted some of my problems in post#1356, 1363 under the RX330. Now I am back to square one.
Just a week ago I traded in a blue RX350 for a bamboo RX350 with full entertainment system. Something I have wanted for a long time and I sunk every dime I had into this car. Now I find that some of the same things are happening that have happened to my previous RX330's. (My previous blue RX350 ran perfectly). I would take it back but I think they sold it.
This is what is happening. During the day, (I live in L.A.) warm climate the car runs perfectly. No problems. As soon as the weather changes, i.e.: I park the car and go to a restaurant for dinner. The temperature when I come out is about 65. The car runs smoothly but now a louder than normal groan/humming sound is coming from where I don't know.
Until I tried switching off the a/c. The noise stopped. I took it to dealer. I asked if it was a serious engine problem or perhaps the a/c condenser? They didn't know because it was warm and they could not duplicate the noise, but would check with a fact rep soon. I am really worried this time. If it's the condenser, hell I'll pay for it. But why does this happen when outside temp changes? Next week we are supposed to have cooler weather and I expect this problem will continue all the time then. It's very embarrassing to listen to this noise when passengers in the car ask what is wrong. I really love the car but cant see living it with this problem forever.
I just don't understand I guess. I mean when I switch the a/c off it stops. So I guess it may be the condenser. I don't know. Yet while listening very carefully I think, I mean I think it is coming from the right side if the engine. This is just a guess is all.
One other strange thing. When I sit in the driver's seat of course I hear the noise. If I put my head down like trying to get underneath the instrument panel I cannot hear the noise! So maybe it has something to do with other components near the top of the engine. I just don't know.
I hope I am emailing you in order and I am sorry for taking any of your valuable time, but I am really at the end of my rope now. Considering I am 73 and somewhat sick I thought this car would last me until I die, but I don't know. I just don't know.
Thanks so much Steve, for any help you can give me, and I am very sorry to be bothering you like this.
#199 of 522 Climate Control
Nov 20, 2006 (11:00 am)
Mr. Wwest - Please be so kind as to view my post #198. I emailed Steve and he suggested I post in this area for possible answers. I will also post in the RX350 Climate Control area as well.
Thanks so much for any help you may be able to give me as it is much appreciated.
#200 of 522 Re: This is copy of email sent to Steve. [rpac]
Nov 20, 2006 (11:56 am)
What you are most likely hearing in your NEW Lexus is the air conditioner's compressor. Lexus has recently switched compressor types/designs. The new one is of a variable displacement using a "swash plate" concept to continuously vary the pumping volume within the range of minimum to maximum.
So while this new compressor still uses an electromagnetic clutch to engage/disengage engine drive, it does not use the clutch to cycle the compressor on and off as a function of refrigerant "demand", useage.
The old style compressor's output volume increased with engine RPM just as does your power stearing pump, usually creating TONS more volume/flow that was really necessary.
The new compressor's pump volume/flow can remain constant virtually regardless of engine RPM, increasing the efficiency substantially.
On the other hand your power stearing pump's fully pressurized excess volume/flow must be bypassed back into the sump, wasting HUGE amounts of energy at sustained high engine RPM levels.
Electric power stearing is now putting that loss to bed.
Variable displacement A/C compressor will also reduce energy losses.
Ford has just announced that the new Ford Edge will even have a variable displacement ATF pump for solving the FWD throttle lag, 1-2 second downshift delay/hesitation, while at the same increasing the transaxle's efficiency greatly.
Oh, you might want to go to your dealer and have them remove/change some of the factory c-best settings such that A)the A/C can be disabled indefinitely, B) and is unlinked from automatic operation in defrost/defog/demist mode, C)and prevent the system from automatically switching into cooling mode when the "human comfort equation" resides on the coolish side already.
This latter one will not only remove the discomfort resulting from coolish and dry airflow blowing into your face it will also help to keep the interior windshield surface warm, hopefully always above dewpoint.
#201 of 522 Thank You Wwest
Nov 20, 2006 (2:54 pm)
Thank you so very much for your most detailed answer to my a/c noise. However, I have one further question that puzzles me. Why does the noise appear ONLY when the temp outside starts to drop to the 60's?
Hot outside, no noise!
Thank you again - you are one in a million! Make that $64 million
#202 of 522 Re: Thank You Wwest [rpac]
Nov 20, 2006 (6:36 pm)
When its coolish outside the variable displacement compressor probably runs at it lowest volume, at least most of the time. Also there could be some sort of mechanical resonance, sympathetic vibrations, involved. Anti-resonance tuning (balance shafts..) is relatively easy when "noises" follow the engine RPM as it rises and falls, but when it doesn't...
The climate control ECU "wants" to keep the A/C cooling evaporator as close to freezing as is possible, typically ~35F, without actually reaching the 32F freezing level. Obviously this would take less refrigerant flow as the OAT gets lower and lower and/or the system blower speed is reduced due to the passenger cabin being (already) near the setpoint and thereby not really needing much cooling capacity.
#203 of 522 Re: Thank You Wwest [rpac]
Nov 20, 2006 (8:32 pm)
I have not encountered this noise, such as you
describe, in my RX350, and I've been driving
in some cooler temperatures.