Rx 330 Air Quality

[seltzerp]

I have an RX 330 with 10K miles. It lives with us in Arizona. In the desert the heat during the day is 100 + degrees. The dry air leaves the vehicle with a musty, mildewor mold smell that is hard to take. The selling dealer states this is a common proplem with no permanent fix. Lexus factory has told the dealer to put the vehicle on a de-ionizer. they also state that the RX 330 has a "sealed" air system and when the air conditioning is only as frequenly as is required in Arizona moisture builds up and mold and mildew develop. They recommend shuting off the re-circulating air to the a/c a few minutes before shuting down the vehile, so fresh air can dry out the closed system. We have a few other vehicles from other manufactures and the air quality has never been an issue in any of them. It appears Lexus did not design an air system for the desert environment. To make matters worse my wife is a highly allergic person. This issue makes owning an RX 330 in this environment a difficult vehicle to tolerate. Suggestions and ideas would be a help. Who needs a Lexus when even our kids Jetta has better air?

[douglasmiami]

Seltzer,

I had same problem with my 1999 RX 300, although mine has 50,000 miles. I took to the dealer and they took apart AC and cleaned. They recommended an AC treatment, but I didn't want to pay for at the time. The cleaning did help the smell, although I still get traces of it. There are several situations that might be taking place. I would do a search on this website for AC to read other strings.

I don't think it's a chronic problem with all Lexus autos. My research leads me to believe it's a random coincidence of events that causes this. And I live in Miami, where it's humid all the time. So overuse also can also cause problems when water sits in the system.

Lexus just topped the JD Powers survey again as the automobile with the one of the fewest complaints per 100 cars.

Good luck.

[wwest]

Okay, here we go again...

First, the odor is from the leavings and out-gassing of the microbes that constitute the "family" of mould and mildew. And second, ALL air conditioners have this problem to some extent.

These microbes really like damp and dark places and thrive and multiply mightily when temperatures are correct, 60-70F, if I remember correctly.

The problem has always existed in automotive A/C system but became much more prevalent when the type of A/C refrigerants was changed back in the early to mid ninties.

The new refrigerants are less efficient so some way had to be found to make up for the loss in efficiency. The most commonly accepted method was to increase the density and complexity of the A/C evaporator. My 84 T-bird had an evaporator with approximately 4400 sq inches of cooling vane surface area, my 92 LS has over 10,000 sq inches. Remember that the total area of the evaporator could not be readily increased, think SPONGE.

The second method also commonly selected to improve efficiency was to more thoroughly SEAL the vehicle such that the already cooled air within the cabin does not readily escape. Other than the obvious, good insulation and sealing makes the vehicle a LOT quieter, this actually has a secondary positive effect in that with less fresh air coming into the cabin the airflow that does enter will flow throught the evaporator vanes very S.L..O...W...L.....Y.....

The longer a unit of air remains with the evaporator the COLDER it will become.

On a humid day when you operate your A/C the air flowing through the evaporator will oftentimes be cooled to its dewpoint, the point at which moisture begins to precipitate out of the air. Cooling humid airflow is like squeezing a sponge, as the air is cooled its capacity for holding moisture is reduced. In this case it condenses out of the cooled air and onto the vanes of the evaporator. As each of these dropletts accumulate more and more mass their viscosity will be overcome by gravity and they will flow down the evaporator and out the condensate drain onto the roadbed.

Remember that while the A/C is operating this is an ongoing process. So when you shut the vehicle down for the evening after a humid day there will ALWAYS be a thin film of moisture still clinging to the evaporator core. As the A/C plenum area warms during the shutdown period absent some sort of forced airflow the moisture will likely evaporate into the local atmosphere making the A/C plenum area VERY humid.

Those microbes will now wake up, become very active, and FALL IN LOVE!

When Lexus shipped my 92 LS they were already aware of the problem and so the evaporator in my 92 LS had a porus nylon film covering the vanes and these pores were filled with an anti-microbial agent, fungicide, at the factory.

That worked very fine to keep the microbes at bay, but with continual use of the A/C day after day those frequent "washings" eventually washed the chemical from the pores and now I was left with an extraordinarily absorbent SPONGE.

Here in the Seattle area our summer nights are not very conducive to the growth of mould and mildew, not typically warm enough. But let me tell you that the moisture left in the A/C plenum overnigh via this method can have a very frightening effect on you when the windshield suddenly fogs over completely about 5 miles down the road on a cool morning.

In January of 93 I had become so afraid of driving my new LS that I parked it in the garage and didn't drive it again until the fall of 93 after I had figured out what was causing this effect and how to overcome it.

I started religiously rolling the windows down slightly in the garage each and every night. Yes I know that this did not create and "forced" airflow, directly, through the system, and today I cannot tell you why or how it worked, actually, but that it did work.

While I did have follow-on instances of sudden windshield fogging, none of them were due to the previous day's A/C operation.

I don't at the moment remember the internet site, but I think if you search for "airsept" and "eed", it will pop up. The eed is a device that will run the A/C blower intermittently starting about 30 minutes after the vehicle is shut down. Apparently it takes about 30 minutes or so for the evaporator to rise from its normal operating temperature of ~33F to a level at which the thin film of mositiure will (might??) begin to evaporate. And then the idea is to use the pressure differential created by the blower motor to move the moisture laden air entirely from the vehicle.

Another thing that seemed to help with my Lexus LS was adding 4 12 volt exhaust fans in the trunk below the shelf package. These fans are activated automatically with the system in defog/defrost/demist mode, or if I activate the rear windows defog heating strips.

I can suggest a more instant but temporary fix. Remove the pollen filter, turn the system to fresh and mixed outflow, (dash & footwell, least airflow resistance) and the blower to HIGH with the windows open and then spray a can of lysol slowly into the system outside air intake at the bottom passenger side of the windshield.

Leave the blower running for 10 or 15 minutes after the lysol is exhausted to purge the remaining lysol fumes.

[wwest]

More....

Combating HORRID dirty gym socks like odors.

The internet page for the EED, Electronic Evaporator Dryer, is:

http://www.airsept.com/eed.html

Another device that might be helpful is a UV light source. For searching, the brand name is BIOZONE and the model is 50V.