RoyalX

Hi,

I have this God awful musty stinky stale smell that eminates from my heater when the heater fan is on (set to temps 65-80+). Does anyone know how I can neutralize this smell?

I have not had the 60K service yet and have 63K miles on my '96 LS400. Might this be caused by the air conditioner filter being too old and useless?

Please note that when the air conditioner is on, the smell vanishes... or when I turn on the Front Defrost vent the smell vanishes.

Basically, I cannot use my heater system when an attractive women is in my car, because of this repulsive smell.

Has anyone else ran into this problem and found a worthy solution.

Thank you,
RoyalX

willard west

Bop over to edmunds town hall and search for "musty" and read that fairly short series of posts, 14 I think.

In the meantime if you can open the sunroof and roll down the windows at night then after about a week most of the smell will be gone.

vipermann1

Are you leaking coolant?

Have you mechanic check the heater core for leaks. There is a gasket that seperates the coolant from the heater core. If it's leaking, coolant is getting into the heater core, causing the smell.

After running the heater for about 10 minutes minimizes the smell, but will return after the coolant gets back into the core after sitting overnight.
(does not effect the airconditioning because air does not need to goto heater core).
Has the same problem in my BMW.

willard west

Anti-freeze, engine coolant fluid, has a sickening sweet smell, not musty.

Running the A/C coats the mold and mildew, and their "leavings" (the actual source of the musty horrid smell) with condensed vapor, suppressing the odor.

Running the heater only, without the A/C compressor, converts the condensate into water vapor which then "floats" away into the system airflow and thus to your nose.

Front defrost(defog/demist) activates the A/C compressor regardless of an actual indication of same.

And s/he lives in a southern state where mositure remaining in Lexus' inordinately complex and dense evaporator core provides an excellent breeding area for the growth of mold and mildew.. In a northern state s/he would be complaining of windshield fogging due to an inordinate level of moisture retention.

jahummer

I have never had that problem with the heater but I have had it with the A/C due to the fact that I used it with recirculate always on and never used the outside vent. Dealer said that this caused mold build up due to a lack of airflow over the evaporator or condensor.

So I diluted bleach with 2 gallons of water and poured it into the air intake in the cowl. I did it with the A/C running with outside vents set to on.

It did the trick. But if I leave the car sit for a week or two, it develops a slight musty smell even though I have shampooed and dried everything thouroughly. I think that a lot of the smells actually come from the materials in the seats and carpeting.

Just my 2 cents...

RoyalX

Thank you for the options.

Your help is much appreciated. I love my LS400 and such a smell really detracts from the quality enjoyment it provides.

RoyalX (Mr. RoyalX)

willard west

If you browse around on the internet a bit you will find DOZENS of products, and product types, designed and marketed specifically to combat the problem of mold and mildew growth within the dark, damp and dank, A/C plenum area containing the A/C evaporator core.

Since about the mid eighties the density and complexity of automotive A/C evaporator cores has increased substantially. It has ALWAYS been the case that once the A/C system was shut down MOST of the moisture just previously condensed on its vanes would accumulate into droplets and run out the condensate drain provided for that very purpose.

That of course is still very true. The problem resides with today's increased level of condensate that remains within the evaporator core due to it greatly extended surface area. A 92 LS400 A/C evaporator has over 10,000 square inches of surface area (vs about 3000 for an 84 T-bird) which in my testing retained over a pint of water for more than 24 hours setting out in the open in an unheated two bay garage.

The primary reason for increasing the density and complexity of the A/C evaporator was to overcome the loss of cooling efficiency due to the (pending) conversion to R-134 refrigerant.

But NipponDenso, the primary A/C supplier in the Japanese automotive market, took it upon themselves to take things a small (but dangerous, as we will see) step further.

We all know that higher A/C fan/blower speeds contribute substantially to the noise level inside the car. But do we all recognize that higher blower speeds also substantially reduce the "single pass" cooling efficiency of the A/C evaporator?

Denso engineers decided that if they could provide an overall automotive A/C "environment" that allowed the blower speed to be reduced to an absolute minmum, then A/C cooling (and dehumidification) efficiencies could be increased phenomenally.

So, not only did Denso increase the density and complexity of the primary working element of the A/C, the evaporator, they required their automotive manufacturing customers, Lexus, Toyota, Honda, etc, to severely RESTRICT the OUTFLOW of cabin air. If you keep the refrigerator door CLOSED, things inside will cool down much faster.

But why all of the EXTRA effort, more complex and dense evaporators than competing A/C designs and manufacturers, much moreso than was warranted by the level of loss efficiency due to the refrigerant conversion to R-134?

Have you ever been discomforted in the wintertime, as an automotive operator or as a passenger, with the need, "requirement", to spend hours upon hours with the climate control system dedicated to "spraying" the interior windshield surface with HOT airflow to heat it, and then keep it heated, so that it doesn't fog over due to the relative humidity being too high within the cabin.

Driving a Budget Jaguar rental car away from Logan airport one very cold and wet, freezing rain, winter night comes immediately to mind. To keep the windshield clear that particular night we had to turn the heat all way up and route all airflow to the windshield. By the time we got to Norwood the Jaguar's cabin was stiffling. Absent the freezing rain we might have been able to lower the windows to make ourselves more comfortable and help lower the interior humidity.

Wet ski clothing, sweaty jogging togs, or just normal human breathing and perspiration, all elevating the relative humidity.

Denso had/has (or so they thought) the answer. Make the A/C system so damned efficient, even in declining wintertime temperatures, that it could continue to extract mositure from the incoming airflow, and the car's cabin, all the way down to the system's minmum operating temperature, just above freezing.

What does all of this add up to?

1. Musty, horrid smells emanating form the A/C system when the dominant overnight (storage, blower off) temperatures are within the range, above 50F, that the growth of mold spores will be promoted by the abundant existence of mositure, and the "food" it inevitably carries along, within the dark A/C evaporator plenum.

2. In predominantly cooler or colder climates the mysterious and spontaneous fogging over of the interior surface of the windshield if the A/C compressor is inadvertantly, manually, shut down after having previosuly (even yesterday, or the day before)operated long enough to have accumulated condensate on the evaporator vanes. Or automatically, "silently", if the OAT declines below 35F, or if you deactivate the defog/demist function having previously turned the A/C compressor off manually.

Two suggestions.

Disable the A/C compressor entirely when the dominant log term temperature is low enough (55F {?}) that its only cause for operating is dehumidification of the incoming airflow. And in this circumstance be fully prepared to quickly implement the old tried and true method of removing windshield condensation and keeping it from reforming. To remove condensation and then to prevent it from reforming, HEAT the windshield interior surface.

Unlike the Denso defog/demist system in your Lexus, this method will work all the way down to sub-freezing temperatures.

If you cannot lower the windows and/or open the sunroof when the car is not being used then have someone install an extraction fan or blower, that runs about about ten or fiften minutes, about an hour after the car is shut down for the day, or long enough for the evaporator that has just been used to rise from its 35F operating temperature to something close to local ambient.

Because these vehicles are so thoroughly sealed, running the existing blower, especially at such low speeds as most manufacturer supplied or aftermarket devices now do, doesn't serve very well to move the airborne mositure content from the cabin, only from the A/C plenum into the cabin.

jahummer

willard, thanks for the in-depth explanation, as always.

RoyalX

simply amazing!

If only I could understand in laymen's terms.

I will always keep my sunroof open... that should help. Also, went I put on the defroster the smell does not seem to appear.

I am still playing around with how to avoid the smell, as painlessly and cheaply as possible.

Thank you,
Britt

jahummer

Well, after several months of running the a/c with outside vent open and not running the compressor all the time I have elimniated all a/c odors and my car now smells like it did not long after I bought it.