Rx300 Horrible Ac/heater Smell During Rain Storms

[LexKid630]

I've always had this problem in my rx300 but never really found the time to talk about it until now.

Whenever we get heavy rain, the glass always seems to fog up on the inside unless i set the controls to "outside circulation". The only problem with this is that during rainstorms i get a very HORRIBLE moldy, musty smell. if i set it back to "inside circulation" the smell eventually goes away, but when i switch to outside air it gets bad again.

Strange thing is, this only happens when it's raining outside. If it's a nice day (assuming no dead skunks on the road) the outside circulation" and "inside circulation" settings both give pleasant results with absolutely no smell at all.

This is all with the temp set between 68-73 degrees (haven't really tested it with any other temps) and the AC button turned off (since i want the air to be warmer). Also set to head and feet.

any suggestions as to what's wrong? I don't notice this in the Rx350 or Ls430 (at least i've never noticed it this much). I've tried researching this on LOC and google with no results specific to the Rx300.

Thanks guys!

[gordonw]

Have you checked your cabin a/c filter?

[tdandkd]

I have the same issue and am interested to find out what the problem is. I'm going to have to fix my blower motor as it is currently stuck on high only but will wait to hear suggestions regarding this smell problem in case something needs to be done in that area.

[LexKid630]

Have you checked your cabin a/c filter?

WOW

i just checked it and it's FILTHY! I never thought to check it today because i checked it in the fall and it was perfectly clean, and it hadn't been cleaned since 2005. I have NO idea how it got so filthy in 6 months when it stayed clean for 2 years... But nevertheless i cleaned it (best i can do for the night) and will see if it still smells tomorrow. HOPEFULLY it rains!

Only thing that stumps me is why this only seems to happen when it's raining out. Could the moisture in the air be the cause?

[wwest]

Google for:

wwest denso demist

And then:

wwest dirty gym socks odor

And read the material plus read about the EED, Electronic Evaporator Dryer, at airsept.com

[LexKid630]

Google for:

wwest denso demist

And then:

wwest dirty gym socks odor

And read the material plus read about the EED, Electronic Evaporator Dryer, at airsept.com

Thanks for that information. So you're thinking that during days when it's raining the moisture is being taken into the car's AC piping etc growing and feeding mold!?

I read about that EED device on the website and still don't know where it goes or what it does specifically. Also the price seems to be hidden.

[mccldwll]

Google for:

wwest denso demist

And then:

wwest dirty gym socks odor

And read the material plus read about the EED, Electronic Evaporator Dryer, at airsept.com

Thanks for that information. So you're thinking that during days when it's raining the moisture is being taken into the car's AC piping etc growing and feeding mold!?

I read about that EED device on the website and still don't know where it goes or what it does specifically. Also the price seems to be hidden.

What wwest has referenced sounds like what is also known in home heat pump and AC systems as DSS--"dirty sock syndrome." It's nasty, and no fun. The mold spores go dormant, and "fragrance" reactivated with moisture. I had it on a Volvo a few years ago, and Toyota had a service to clean/disinfect. Since then, I have followed advice to run AC with fresh air position except when initially cooling down, and also to turn off AC a mile or two before destination (on Volvo, this related to giving system to drain to help prevent situation where mold and other crap in condensation collector clogs drain and overflows onto passengers feet).

[gordonw]

Have you checked your cabin a/c filter?

WOW

i just checked it and it's FILTHY! I never thought to check it today because i checked it in the fall and it was perfectly clean, and it hadn't been cleaned since 2005. I have NO idea how it got so filthy in 6 months when it stayed clean for 2 years... But nevertheless i cleaned it (best i can do for the night) and will see if it still smells tomorrow. HOPEFULLY it rains!

Only thing that stumps me is why this only seems to happen when it's raining out. Could the moisture in the air be the cause?

I recommend you replace the ac filter every 10-15,000 miles, instead of just cleaning it. You also may want to try some Frigi Fresh. Its used by most dealerships, and works pretty well. I've also read some people have used a product called Ozium, but I don't have any experience with that product.

[wwest]

Google for:

wwest denso demist

And then:

wwest dirty gym socks odor

And read the material plus read about the EED, Electronic Evaporator Dryer, at airsept.com

Thanks for that information. So you're thinking that during days when it's raining the moisture is being taken into the car's AC piping etc growing and feeding mold!?

I read about that EED device on the website and still don't know where it goes or what it does specifically. Also the price seems to be hidden.

In any modern day car with A/C anytime you use that A/C, and then subsequently shut it off, a few ounces (or more, perhaps a LOT more) of condensate, condensed water, will always remain as a thin film on the approximately 10,000 square inches of A/C evaporator vane cooling surface area. If left in that condition for an extended period, night after night, the evaporator surfaces and surrounding HVAC plenum soon will become an EXCELLENT breeding gound for a myriad of microbes that constitute the family that contribute via their "leavings" to the buildup of mold and mildew on these surfaces.

An easy way to combat this problem, inexpensively, is to simply leave your windows down each and every night in the garage.

The EED is an alternative and is actually used by many of the Ford dealers around the country if customers make enough "noise".

All the EED does is activate the HVAC blower for a few seconds every few minutes for up to an hour after the ignition is switched off. While actually operating, the temperature of the A/C cooling vanes will approach 35-33F. The blower activation, bringing in outside fresh airflow, will result in those cooling vanes rising to the ambiant temperature fairly quickly and shortly thereafter the thin film of moisture will begin to evaporate and the blower will then whisk it away to be distributed throughout the cabin.

The result?

No dark, dank, and DAMP breeding ground for those microbes and no more early morning incidences of sudden windshield fogging over about five miles into the coolish morning drive.

For my '01 AWD RX300 there was several C-best options available that allowed me to address this problem in a more direct way.

One C-best option allows me to disable the A/C compressor indefinitely by simply switching it off one time via the pushbutton. The second C-best option unlinks the A/C from operatingautomatically in full or partial defrost/defog/demist mode.

So I leave my RX's A/C completely disabled throughout the winter months.

That little car to you left has a switch in the glove box so I can open the A/C compressor clutch circuit throughout the winter months.

In days of yore I always disconnected the A/C compressor clutch circuit under the hood during the winter months.

In the olden days the A/C system could be used as an aid, a valued and valuable aid in defogging/demisting the windshield but not today, no more.

[LexKid630]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

[RX in NC]

Be aware that ever since the advent of air conditioning systems in vehicles, automotive A/C technicians have collectively advised all motorists to periodically operate their A/C systems for at least a few minutes per week even during the winter months. The reason typically given for doing so was that this is necessary to keep the various sealant compounds within the A/C unit properly lubricated so as to minimize the chances for freon leaks occuring. As we all know, freon formulas have changed over the years from R-12 to R134a but the advice that A/C techs offer to their customers hasn't changed - they still tell you to run your A/C from time to time to help protect the seals. Not being an expert in A/C design and function, I can't attest to the validity of this advice and I have to admit that I do not run the A/C in my primary vehicle for at least a few minutes every week year-round as advised. But I do run it at least once a month even during the winter months, usually for no more than 5 minutes....

[mccldwll]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

The mold spores probably are located in the drain basin by the outside air intake. The mold is being reactivated with rain. The Frigi Fresh mentioned by someone, or similar product, may work. If not, possibly a more aggressive flush of area or even physically accessing the area for cleaning (not sure how--I'm too new to the RX to know how difficult that would be). The source of your mold spores probably is from vegetation partially clogging that exterior drain, never allowing it to fully drain/dry, AND by keeping the fresh air vent closed so doesn't dry.

[Grumpa72]

It has always been my understanding that you should ALWAYS leave your circulation button on outside to keep the moisture content of your vehicle down. The only time I ever use inside circulation is immediately upon entering an extremely cold or hot vehicle. Then, you are using the already conditioned air to heat/cool the cabin. After 2-3 minutes of this, though, I always switch back to outside circulation. By using inside air, you circulate the air that is laden with moisture and contribute to the fogged window problem. From an anatomy point of view, the human lung is a great moisture pump.

As others have pointed out, proper maintenance of your hvac system is critical. You may already have mold spores but I think I recall reading that there are sprays that can be added to the system that will kill mold. With your a/c on, do you get the extracted moisture dripping out underneith? I ask because I had an older Mercedes that had a plugged drain line and it allowed moisture to back up into the car. Cleaned out the natsy plug that was there and no more problems.

Gary

[mccldwll]

It has always been my understanding that you should ALWAYS leave your circulation button on outside to keep the moisture content of your vehicle down. The only time I ever use inside circulation is immediately upon entering an extremely cold or hot vehicle. Then, you are using the already conditioned air to heat/cool the cabin. After 2-3 minutes of this, though, I always switch back to outside circulation. By using inside air, you circulate the air that is laden with moisture and contribute to the fogged window problem. From an anatomy point of view, the human lung is a great moisture pump.

Gary

In the summer, outside humidity in many places far, far higher than lung output. Still, it's best to run in fresh setting, except for initial cooldown (or in tunnels).

[wwest]

It has always been my understanding that you should ALWAYS leave your circulation button on outside to keep the moisture content of your vehicle down. The only time I ever use inside circulation is immediately upon entering an extremely cold or hot vehicle. Then, you are using the already conditioned air to heat/cool the cabin. After 2-3 minutes of this, though, I always switch back to outside circulation. By using inside air, you circulate the air that is laden with moisture and contribute to the fogged window problem. From an anatomy point of view, the human lung is a great moisture pump.

Gary

In the summer, outside humidity in many places far, far higher than lung output. Still, it's best to run in fresh setting, except for initial cooldown (or in tunnels).

Yes, during the summer months the largest body organ takes over from the lungs as the primary supplier of additional cabin humidity.

Remember, with regard to FE, it is advantagous to keep "conditioned" air within the cabin as long as is feasible. So manufacturer's are going to what some of us consider extreme measures to reduce the cycling of the A/C via this "double gain" (noise reduction too) method. Lowering the rear windows just ever so slightly as you drive will definitely be of an aid, and lowering then all the way otherwise will DEFINITELY be of an aid..

[wwest]

Be aware that ever since the advent of air conditioning systems in vehicles, automotive A/C technicians have collectively advised all motorists to periodically operate their A/C systems for at least a few minutes per week even during the winter months. The reason typically given for doing so was that this is necessary to keep the various sealant compounds within the A/C unit properly lubricated so as to minimize the chances for freon leaks occuring. As we all know, freon formulas have changed over the years from R-12 to R134a but the advice that A/C techs offer to their customers hasn't changed - they still tell you to run your A/C from time to time to help protect the seals. Not being an expert in A/C design and function, I can't attest to the validity of this advice and I have to admit that I do not run the A/C in my primary vehicle for at least a few minutes every week year-round as advised. But I do run it at least once a month even during the winter months, usually for no more than 5 minutes....

Going all the way back to my '68 Ford Country Squire station wagon, discarded at not less than 270,000 miles, I have always disconnected my A/C compressor clutch circuit during the winter months and never incurred a failure as a result. The only refrigerant leak I remember having was due to a pinhole in a hose of a '71 Mustang. Oh, our '88 911's A/C needs to be recharged about every two years but that is SOP for that model.

[wwest]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

It does begin to sound as if in your particular case you might have a small animal or bird that has died inside the fresh ducting somewhere.

Remove the pollen filter and use an inspection mirror and flashlight to thoroughly examine the ductwork immediately above the filter. Do the same from the outside.

[mccldwll]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

It does begin to sound as if in your particular case you might have a small animal or bird that has died inside the fresh ducting somewhere.

Remove the pollen filter and use an inspection mirror and flashlight to thoroughly examine the ductwork immediately above the filter. Do the same from the outside.

It won't take an animal or bird, and they would create a full time decay smell. The fact that oder comes with rain/moisture definitely points to mold spores being reactivated--classic DSS.

[wwest]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

It does begin to sound as if in your particular case you might have a small animal or bird that has died inside the fresh ducting somewhere.

Remove the pollen filter and use an inspection mirror and flashlight to thoroughly examine the ductwork immediately above the filter. Do the same from the outside.

It won't take an animal or bird, and they would create a full time decay smell. The fact that oder comes with rain/moisture definitely points to mold spores being reactivated--classic DSS.

I disagree. Mold spore colonies need/REQUIRE a dark and moist, WET, environment with a consistent or often recurring ambient temperatrue (garage, parked, nightime) in the range of 65-75F in order to survive, breed, multiply. Historically with regards to automotive A/C systems that has been found to have been pretty much restricted to the evaporator surfaces and the surrounding plenum "tank" area.

Additionally all system airflow, fresh or recirculate, flows through the pollen air filter so it is unlikely the problem is with the filter, of even downstream of it.

Each spring I have the task of opening our furnace and removing the dead mice that our cat has brought in over the winter and allowed to escape down one of the air vents. I'm quite certain that were I to somehow "hydrate" one of those otherwise quite thoroughly dry mouse bodies the resulting odor would be nothing short of putrid.

[mccldwll]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

It does begin to sound as if in your particular case you might have a small animal or bird that has died inside the fresh ducting somewhere.

Remove the pollen filter and use an inspection mirror and flashlight to thoroughly examine the ductwork immediately above the filter. Do the same from the outside.

It won't take an animal or bird, and they would create a full time decay smell. The fact that oder comes with rain/moisture definitely points to mold spores being reactivated--classic DSS.

I disagree. Mold spore colonies need/REQUIRE a dark and moist, WET, environment with a consistent or often recurring ambient temperatrue (garage, parked, nightime) in the range of 65-75F in order to survive, breed, multiply. Historically with regards to automotive A/C systems that has been found to have been pretty much restricted to the evaporator surfaces and the surrounding plenum "tank" area.

Additionally all system airflow, fresh or recirculate, flows through the pollen air filter so it is unlikely the problem is with the filter, of even downstream of it.

Each spring I have the task of opening our furnace and removing the dead mice that our cat has brought in over the winter and allowed to escape down one of the air vents. I'm quite certain that were I to somehow "hydrate" one of those otherwise quite thoroughly dry mouse bodies the resulting odor would be nothing short of putrid.

Constant moisture is not at all necessary. The spores simply go dormant and "revive" and thrive when appropriate conditions reoccur.

Unfortunately, I've personally had to deal with mold spores in the following: 1) identical to this but not on an RX where the actuator for the fresh air flap was not working correctly; 2) in a home where a leaking valley resulted in water infiltrating a wall necessitating involvement of an environmental engineer and $$$ remediation; and 3) new variable speed high efficiency heat pump where "organics" that accumulate during cooling season from moisture which never fully dissipates from fins, as you mentioned above, dries and goes dormant between summer and winter. During heating season, when unit goes into defrost mode the moisture reactivates spores, resulting in offensive oder commonly known as "Dirty Sock Syndrome"--DSS. Once there, cleaning won't fix it beyond short term. The hvac industry has been trying for several years to escape any responsibility, but when homeowners push hard enough, will often receive a new epoxy coated indoor coil. I did. I have a copy of a Trane memo to dealers on the problem.

[wwest]

Can't you just disable the AC by not turning the AC button on? I haven't turned the AC button on since the Fall and still the problem occurs.

And why is it only when it rains and set to "outside circulation"? If set to "inside circ" it doesn't create the smell. Id the problem was indeed in the vents etc wouldn't the smell be evident at all times when the fan is on?

It does begin to sound as if in your particular case you might have a small animal or bird that has died inside the fresh ducting somewhere.

Remove the pollen filter and use an inspection mirror and flashlight to thoroughly examine the ductwork immediately above the filter. Do the same from the outside.

It won't take an animal or bird, and they would create a full time decay smell. The fact that oder comes with rain/moisture definitely points to mold spores being reactivated--classic DSS.

I disagree. Mold spore colonies need/REQUIRE a dark and moist, WET, environment with a consistent or often recurring ambient temperatrue (garage, parked, nightime) in the range of 65-75F in order to survive, breed, multiply. Historically with regards to automotive A/C systems that has been found to have been pretty much restricted to the evaporator surfaces and the surrounding plenum "tank" area.

Additionally all system airflow, fresh or recirculate, flows through the pollen air filter so it is unlikely the problem is with the filter, of even downstream of it.

Each spring I have the task of opening our furnace and removing the dead mice that our cat has brought in over the winter and allowed to escape down one of the air vents. I'm quite certain that were I to somehow "hydrate" one of those otherwise quite thoroughly dry mouse bodies the resulting odor would be nothing short of putrid.

Constant moisture is not at all necessary. The spores simply go dormant and "revive" and thrive when appropriate conditions reoccur.

Unfortunately, I've personally had to deal with mold spores in the following: 1) identical to this but not on an RX where the actuator for the fresh air flap was not working correctly; 2) in a home where a leaking valley resulted in water infiltrating a wall necessitating involvement of an environmental engineer and $$$ remediation; and 3) new variable speed high efficiency heat pump where "organics" that accumulate during cooling season from moisture which never fully dissipates from fins, as you mentioned above, dries and goes dormant between summer and winter. During heating season, when unit goes into defrost mode the moisture reactivates spores, resulting in offensive oder commonly known as "Dirty Sock Syndrome"--DSS. Once there, cleaning won't fix it beyond short term. The hvac industry has been trying for several years to escape any responsibility, but when homeowners push hard enough, will often receive a new epoxy coated indoor coil. I did. I have a copy of a Trane memo to dealers on the problem.

As I said, Often recurring. conditions.

But there is problem, downside, to coating the evaporator vanes.

Almost any coating will result in undesireably reducing the heat transfer efficiency from the COLD refrigernat gas inside the evaporator to the airflow over the vanes of the evaporator. So maybe that is why the HVAC manufacturers are so reluctent to respond to these complaints. There is no good, simple, answer.

Even worse yet...

The early LS400s came with a thin porus nylon coating covering the entire evaporator vane surface area. An anti-microbial fungicide was embedded within these pores during manufacturing. As long as a sufficient level o fteh fungicide remained within those pores the mold and mildew spore problem was abated.

But.

Over time and hundreds of A/C use "cycles" the fungicide was "washed" from the pores.

Guess what happened next..??

Those pores, collectively (10,000 square inches of evaporator cooling vane surface area) began acting as one HUGE sponge. Not only that but because those pores were of a reasonably consistent size the moisture held within them after a period of A/C operation would not evaporate as willingly as before (fluid viscosity, capillary function, and all that). So only once the the local atmosphere within the plenum area rose to a VERY specific, tight tolerance level, then all of those pores would begin to release their moisture to evaporation virtually simultaneously.

BLAP.., BLAM.., BANG...!!!

That was a MOISTURE EXPLOSION you just experienced.

About 5 miles into your morning drive the cabin suddenly begins to be humidified, HUMIDIFIED(bold. caps) and now if its just a tad coolish outside your windshield is sudden fogging over to the point wherein you must pull quickly to the side of the road all while have virtuall not forward vision. Or maybe you're just driving along and by pure happenstance the OAT declines below the point wherein the continued function of the A/C is allowed and now within a few miles you REALLY have windshield fogging problems.

Some LS models today have a UV light source inside the evaporator plenum area to !Removed! the growth of these microbes.

[mccldwll]

But there is problem, downside, to coating the evaporator vanes.

Almost any coating will result in undesireably reducing the heat transfer efficiency from the COLD refrigernat gas inside the evaporator to the airflow over the vanes of the evaporator. So maybe that is why the HVAC manufacturers are so reluctent to respond to these complaints. There is no good, simple, answer.

Yep. Definitely decreased efficiency, though I've never determined specific %. But I was more than happy to trade the efficiency for better air quality.

[LexKid630]

So what do you suggest i do about this problem? Yesterday it didn't rain and the smell wasn't present. Today it rained and the smell was back!

I ruled out the filter as the problem. Tonight i took the filter material out and ran it for a while and the smell was still as strong. And it's ONLY when i have it set to "outside circulation".

Could this be a warranty thing? I'm still covered with my CPO warranty. Thanks!

[mccldwll]

So what do you suggest i do about this problem? Yesterday it didn't rain and the smell wasn't present. Today it rained and the smell was back!

I ruled out the filter as the problem. Tonight i took the filter material out and ran it for a while and the smell was still as strong. And it's ONLY when i have it set to "outside circulation".

Could this be a warranty thing? I'm still covered with my CPO warranty. Thanks!

I doub't you'll find a warranty issue/manufacturing defect unless there is something out of norm from day 1 constricting the drain channels predisposing it to this condition. It sounds like "organics" condition probably developed from windshield drain area channels clogging, possibly from small leaves/windshield crud, then area not drying quickly enough. Once contaminated, reactivated by moisture.

I have zero idea how difficult it is to access the area to thoroughly clean/disinfect. Once accessed, IIR, wwest above discussed a treatment used on cooling fins. Similar products exist for post-remediation treatment in houses. Probably something for metal/plastic surfaces, which will be much easier to successfully clean than porous surfaces. Good luck.