Clean Driving Machine

Updated on September 24, 2015

Can’t Stay Awake

Recently, our 2-year-old car started making me drowsy on drives over an hour. Later that evening, my sleep was poor and my body felt agitated. These are not good signs. Even though the car smelled fine and I was good about keeping it clean, apparently there was an issue developing most likely with the ductwork. Below is what I did to clean the car. I no longer get drowsy.

Cleaning Car Air Conditioning Mold

Air Conditioning Basics

If your car has air conditioning, it has a small (roughly 8”x8”x1”) evaporator core that looks like a baby radiator packed inside the plastic ductwork under the middle of the dash near your feet. Warm outside air is cooled as it’s blown through the Freon cooled evaporator core into the cabin. Just like water condenses on your ice filled drink sitting outside, water condenses on the fins of the cold evaporator. There is a drain line that takes this water as it drips off the evaporator and dumps it on the ground under the car – maybe you’ve seen this water dripping from under cars sitting in traffic on a warm day.

Car Ductwork

Unfortunately, knowing that mold will grow whenever there is food and water present, it’s not hard to imagine that having A/C may lead to mold issues. After all, even if you have a newer car with a cabin filter (usually behind the glove box), some dirt always gets past the filter and can collect on the core. This is all the food mold needs.

Even if your vehicle doesn’t have A/C, it will have a heater core. Just like the evaporator core, the heater core is a small radiator fitted inside the plastic ductwork under the dash. I personally don’t see much chance of mold starting on a heater core, but I suppose it’s possible. Let’s say you live in New Orleans where it’s damp a lot but not cold enough that heat is required. In this case, damp air passes through the heater core and with the dust that’s collected, it may be enough to grow mold. I think this is a fairly unlikely scenario because usually when it’s damp it’s also cool enough that the heater is used. When in use, the warm coolant from the engine passes through the heater core and dries it off.

Note: Most online parts stores have exploded diagrams of the ductwork and the core placements within them.

Evaporator & Heater Core Washing

If you do a bit of searching online, you’ll see that they sell pressurized cans of “auto air conditioner cleaner”. It’s advertised as the fix for when your car smells. As an aside, from where I come from, if it’s gotten to the point where your car smells and you have Biotoxin Illness like I do, I’m not sure any amount of cleaning will do.

I purchased a can of this type of product and it has a strong “lemony” smell to it that lasts for 24 hours and lingers on afterwards. I would not recommend this for people who are chemically sensitive. These products are applied by snaking a tube up through the drain line mentioned above and then spraying the cleaning foam into the ductwork compartment that houses the evaporator and heater cores. As the foam works on the dirt and mold it turns to a liquid that then carries the debris out the same drain line. Even if it didn’t smell, I’m not convinced that the relatively small amount of product in these cans is enough to flush out the evaporator and heater cores.

Nozzle Tip

So I came up with my own method using a product that contains quaternary ammonia called KCT QUAT. Dr. Shoemaker recommends using products that contain quaternary ammonia for mold cleanup. By the way, quaternary ammonia is the active ingredient in Cholestyramine – a proven mold toxin binder that people ingest. I purchased an inexpensive pump-sprayer and fitted it with an undercoating tip by drilling out the sprayer nozzle such that the plastic line with the brass spray nozzle fitted at one end could have the other end press fit into the sprayer. (Note: Be careful to buy a flexible undercoating wand that has a small line like mine as some are larger and meant to hooked up to a spray gun.)

Access Hole

By carefully reviewing the exploded diagram of my car’s ductwork, I was able to locate places where I drilled holes and inserted the sprayer wand. Caution: You have to be very careful about drilling holes! Start with a small 1/16” or so bit that you just drill through the plastic with and then fish around inside with a wire to ensure you really are in a good place. After increasing the hole size to 3/8”, I actually used a remote fiber optic camera that I have for work to confirm I had access to all sides of the two cores. In fact, I was surprised to see that a roll-up flapper blocked access if the temperature controls weren’t set properly. Take your time and watch the video.

Spray Cores

In total, I drenched the two cores by running about one gallon of QUAT solution into 3 access holes. After waiting for the cleaner to work, I followed up with another gallon of clean water. As I sprayed, I was particular about moving the spray tip in-and-out and up-and-down to ensure all parts of the cores were soaked. When the entire job was complete, I ran the car and turned the fan and heat on high to dry everything out.

KCT QUAT (quaternary ammonia)
Four 1-Gallon Jugs of KCT QUAT – Many Year Supply
Multi-Purpose Pump Sprayer
36″ Flexible Undercoating Wands

Ductwork Fogging

Fogger & Filter & Quat

Although I didn’t see anything in the plastic ductwork that connects the evaporator and heater cores to the vents in the dash and down by the floorboard, I changed my mind from what I stated in the video and decided to clean this ductwork afterall. Using a FogMaster Junior, I mixed up a solution of KCT QUAT and introduced it into the ductwork in three places.

Fogger Inlet Vent

I started by removing the cabin filter located behind the glove box. With the car fan on high and all the vents open, I misted the QUAT solution into the opening for the cabin filter directly above the blower. I was careful to not get carried away and potentially short the blower with too much liquid. (Actually, I don’t think this is much of a risk but it’s something to keep in mind.)

Fog Blower Housing

I then put the cabin filter cover back in place while leaving the filter out and introduced more QUAT mist into the air inlet holes located under the hood next to the firewall. Again, the fan was on high with the vents open and the air flow set to outside air – not on recirculate. I finished the job by turning off the fan and misting more QUAT into each of the vents on both the dash and in the car doors.

It should be noted that I did not try to rinse out the QUAT solution as I did when cleaning the cores. The directions said you don’t need to rinse. To check this, I made a test sample and let it dry. It wasn’t in any way tacky or smelly so I felt comfortable doing this. As mentioned, everything was then dried out by running the heater and fan on high.

Carpet & Upholstery Cleaning

RugDoctor Carpet Cleaner

I cleaned the carpeting and seats with Bissell BigGreen carpet cleaner – you can rent them at Lowes. I added a little Thieves cleaner to the water – I never use the usual cleaners because of the smell. In the future, I will experiment with QUAT but didn’t think to use it this time – you need to make sure it won’t discolor the seats or carpeting.

Update December 7, 2014: We recently cleaned all the carpets inside our home and the carpeting on our second car using KCT QUAT. I doubled the recommended rate by using a little less than 1/4 cup in each 2 gallon container with hot water. We rented a Bissell BigGreen Carpet Cleaner from Lowes. What a terrible experience.

I had to return the first BigGreen as it had a dead electric drive motor for the power brush. I had to return the second one as it did not stop spraying water even when the trigger was released. The third BigGreen worked but leaked water constantly from the back of the machine – we made due by putting towels underneath it while it sat in one place as we did the stairs inside. To top it all off, the plastic tube that attaches to the upholstery tool broke in half under normal use. The woman at the Lowes service desk said she owned a BigGreen and it leaked too.

This is the last time I’m going to use a Bissell BigGreen Carpet Cleaner! I don’t care if the Amazon reviews are positive; these machines don’t hold up. On the other hand, I don’t know how many Rug Doctor carpet cleaners I’ve rented over my lifetime but I can’t recall ever having to take one back because it wasn’t working. I see that the new Rug Doctors use more plastic but if their previous models are any indication, they should hold up great. End Update

Young Living Thieves Household Cleaner
Rug Doctor Mighty Pro X3 Family Pack

Interior Cleaning

The entire interior was wiped down with more QUAT solution. I wore gloves and goggles and left all the doors open for ventilation – not that it’s smelly but I’m super careful nowadays.


The final step was to flood the car with ozone for several hours with a contractor’s grade Bio3Blaster Pro Rugged Junior ozone generator from Charles Boday. These generators are far ahead of competitive ozone generators with a massive 1.5 horsepower blower and four replaceable 3300 mg generator paddles that produce enough ozone to do my entire house – more about that in another post.

Ozonator Mechanicals

By the way, you may run across EPA information or articles like the one by Mr. Pinto attempting to argue that ozone is flat out bad. However, if you read carefully, they never argue that ozone doesn’t work at neutralizing odors and mycotoxins. The core of their arguments are that combining ozone with raw chemicals is bad and that ozone in high concentration is harmful to people, animals, and plants. Mr. Pinto also tries to argue that ozone is best applied in special chambers even though the auto and fire remediation industry have been using ozone to neutralize odors in buildings and cars for a long time for the simple reasons that it works and doesn’t cause any real damage.

Ozonator Paddles

So what about noxious chemicals and breathing ozone? In the case of noxious chemicals, the EPA technicians mixed ozone with raw chemicals in a laboratory and not surprisingly, it did produced harmful chemicals. Similarly, Mr. Pinto sites a case where contractors that applied a floor finish in one part of a building while ozonating another ended up with a toxic smelling mess. Please note that this is quite different from using ozone on finished materials where the chemicals are bound up. It’s like comparing apples to oranges. Is there a certain degree of toxic chemicals produced when ozone reacts with finished building materials and does rubber and electrical wiring get degraded? Most likely yes, but in the real world there is plenty of evidence suggesting these effects are inconsequential.

Regarding breathing ozone, if you haven’t already been warned, breathing high concentrations of ozone is bad for your lungs. So please don’t do this! Make sure to hold your breath when you go in to open windows and doors after ozonating and wait until the air has cleared before you re-enter the building.

So I don’t think we all need to cower in the corner at the mention of the word ozone. In Europe, ozone has been used for medical reasons for over 50 years and is also how they keep swimming pool water clean without using chemicals like Chlorine. Mr. Pinto is ill informed regarding the medical benefits of ozone. The fact that ozone reacts and releases an oxygen molecule in medical applications is one of the reasons why it helps the body heal. It’s called oxidative stress. When administered in appropriate doses (never by breathing), it stimulates the body’s immune system thereby aiding healing. Anyway, I’ve deviated a bit from the point at hand.

Flood Your Body with Oxygen

To me arguments against ozone are overblown and misleading. If you leave your pet and plants inside an area that is being ozonated, it won’t be good. If you only use tiny amounts of ozone that are at levels safe for people to breath then guess what; it won’t do anything. If you apply finishes or use cleaning chemicals in proximity to stronger concentrations of ozone, expect trouble. If you have some serious breathing or MCS issues, then maybe it’s not worth the risk – even if it is quite small. In other words, if you’re incapable of behaving with a modicum of common sense, then avoid ozone. Otherwise, there are studies showing it works against mycotoxins and it has been used for a long time with real benefit.

… Detoxification of Mycotoxins Using … Ozone
Ozone Applications to Prevent and Degrade Mycotoxins

I think the valid point these negative articles make is that you have to be careful using stronger concentrations of ozone. In the case of Mr. Pinto, maybe he’s right and contractors should be scared away from using ozone for legal reasons. After all, you can never be sure the guys on the job site won’t mess up and forget to ask the owner if they put the family pet outside. You can’t predict how a lawsuit will play out when owners go into a house that’s being ozonated for lunch because they forgot to pack a lunch and were too cheap to buy snacks from the local gas station – even if you did warn them that this was bad for their health.

Ozonate Car

In practice, I keep the windows closed and the fan running on recirculate with a battery charger hooked up to keep the battery from being drained. I set the machine outside so it has an infinite supply of oxygen rich air to convert to ozone. You don’t want the machine inside the space you’re treating, as it will use up the available oxygen to make ozone and then it will start making noxious by-products when there isn’t enough oxygen left to convert. After, I’m careful to open all the doors so the ozone clears out. At the heavy rate I apply it; the car does still smells a bit like ozone for a couple of days after but then smells perfectly clean. I’ve never noticed any negative health effects but then I’m careful not to do dumb stuff like climbed into the car while it is being ozonated 😮

General Tips

Sunny Car

Tip 1: Sunlight Neutralizes Mycotoxins
When it’s sunny out, I park the car outside because sunlight destroys mycotoxins. At night and in rainy weather, the car is put into the garage. In general, I’m trying to reduce the car’s exposure to moisture and increase it’s exposure to sunlight.

The Journal of Applied Poultry Research published the article, Aflatoxin Decontamination of Artificially Contaminated Feeds by Sunlight, Y-Radiation, and Microwave Heating where the authors wrote, “…The photodegradation of aflatoxins (a type of mycotoxin) was found to increase with increased duration of exposure time (Table 1). Greater degrees of aflatoxin degradation were observed with increasing the length (time) of exposure to solar radiation. The calculated percentages of AFB1 and total aflatoxin degradation when exposed to sunlight are presented in Table 2. More than 60% of the aflatoxin was found to be degraded after 30 hours of exposure to sunlight…”

Tip 2: Turn Off A/C & Defrost Ten Minutes Before Arrival
Given the amount of water condensate that builds up on the evaporator core when the air conditioning is on, I always turn off the A/C at least ten minutes before I get to my destination while leaving the fan on high. By drying out any water in-between all those closely spaced fins, I don’t give mold a chance to get a foothold while I’m in the store shopping. If it’s a humid day, I’ll even turn on the heat.

Although you may not realize it, on newer cars when you turn on defrost the air conditioning comes on. This is to help dry out the air so it will clear your windows quicker. As such, I also turn off the defrost 10 minutes before getting to where I’m going while leaving the fan on so the evaporator core dries out. Of course, you need to safe first so if your windows start fogging up you’ll need to try cracking a window or increasing the heat.

Tip 3: Keep Car Outside in Winter

In the past, I parked the car inside our attached garage. Even though it’s unheated, being out of the wind along with the heat radiating from the house, means the garage is almost always slightly above freezing. As such, the snow and slush on the car melts and collects in a pool under the car overnight. The heavy frost on the garage door windows indicates the higher humidity in the garage. In the future, I will be leaving the car outside except when inclement weather draws in to keep it away from these higher moisture levels – guess I better get used to scrapping windows again 😐

Floor Mat

Tip 4: Carpet Mats

In winter, we get snow. I always install rubber floor mats with a substantial rim that runs around the perimeter. When the heat is on, the mat acts as a catch basin for the snow that melts off my boots. I’m careful to mope up this liquid before it gets excessive and overflows the mat. Even if the carpeting material is mold resistant, the dirt that accumulates in the carpeting is more than enough to feed mold. Keeping the car outside most of the time will also help to control any mold that does try to get started.

Tip 5: Drain Holes
At the bottom of doors, tailgates, rocker-panels, fenders, and elsewhere are a set of holes that allow water that gets into hidden spaces within your car’s body to escape. When I wash my car, I take the time to ensure these holes haven’t gotten plugged up with debris. In fact, when I was younger I never gave this a second thought until one day I lifted up the carpeting covering the spare tire to check its pressure only to find it sitting in a pond of water. Oh yeah, that was really good for my health.

Tip 6: Crack the Windows & Avoid Re-circulate
Rather than getting all my fresh air through ductwork that may be less than clean, I like to drive with a couple of windows slightly open. In my cars, I always crack a front and a back window that are opposite sides. It balances out the “wind buffeting” thereby eliminating the oscillating “whomp-whomp” sound from only having one window open.

In a similar vein, when you press the re-circulate button on your car so it cools down quicker with the A/C on, you are not allowing any fresh air in from outside. You’re re-circulating the air in the cabin. I’ve read numerous reports on how using re-circulate a lot leads to mold issues. I can see using it to cool the car down on a hot day, but otherwise let that fresh air in.


Having Biotoxin Illness means having to learn all about mold toxins. There is plenty of talk about water-damaged buildings and the toxins they give off. I can tell you first hand, that vehicles can also be problematic. Hopefully this post has helped you understand not only what to do to minimize the chances for mold in your vehicle but also how to clean it well.

8 thoughts on “Clean Driving Machine

  1. Thank you so much for the detailed instructions. I was trying to find something like this online just a few weeks ago, and ended up paying a radiator company to take everything apart and wash it by hand with soap I provided them – $600. I think we’ll try your approach with our other car.

    • wow kim $600 and they only used soap and water. Is the smell gone at least or do you feel any better in the car? I’ve got a problem with my Honda I think too. Wish I had the know-how to do stuff like this but no way.

      Greg, the kct quat product is sold out. Will any quat product do or is kct quat special in some way?

      • Dr. Shoemaker specifically mentions quaternary ammonia. It’s got a particular molecular structure that makes it a sponge for soaking up Biotoxins.

        Yes, I noticed Amazon was out of KCT QUAT. I just bought four gallons. If you’re interested, you can Google “KOR692-31 Kct Conc No Rinse EPA Quat Disinfectant”.

      • Yes, the vent cleaning did work. I also gave them 10% hydrogen peroxide in a spray bottle to use.

        That said, my car developed a moisture problem in it, and got moldy anyways. Separate from the air vent system.

        I’m selling it (with full disclosure!), but first we cleaned it with a combo of alcohol and grapefruit seed extract. That made it a lot better, but not good enough for me.

        My husband’s car took vent cleaning, surface cleaning with QUAT product, and then repeated ozoning. On my husband’s car we did both the grapefruit seed extract in alcohol (vodka, Everclear or Clear Springs probably would have been better) once. And we vacuumed repeatedly.

        Then he applied the quarternary ammonium product (we used BenzaRid, but Greg’s stuff is probably better). More vacuuming. Then ozone. Each step seemed to help. I’m very chemically sensitive, and couldn’t do the alcohol or ammonium product myself. But once they dried it was actually fine.
        We touch it up with ozone periodically, using Greg’s video as a guideline. Thank you, Greg!

  2. Hey there – thanks for the great article. Im wondering if this Quaterny Ammonia solution is toxic? I have chemical sensitivities and there is no way I can use this stuff if it’s toxic in any way.

    • There is a very faint smell that dissipates in a few hours. However, I’m not particularly sensitive. It wouldn’t surprise me if those that are more sensitive would find QUAT to be too much. Depending on the level of cleaning required, wiping down with hydrogen peroxide may be enough. For serious contamination, there is Greg Weatherman’s protocol. Mix up 2oz of EverClear in 32oz of water. Spray it on, let sit for 3 minutes, then wipe with clean throw-away paper towels. Follow up with 1 cup of borax in 32oz of water. Apply, let sit for 3 minutes, then wipe clean. (Yes, that’s EverClear as in the drinking alcohol.)

  3. This comes in a timely manner as our house has mold and i am sure our car has mycotoxins and we have to check it for mold (motor ,AC etc). I am sensitive to chemicals, what cleaning approach would you recommend? And should we dispose of carpets? Black mold was not found at our home, but others have. Thank you. Eva

    • Eva,
      What are you trying to clean? You can look at the article Mold Remediation 1 and Dr Shoemaker’s FAQs. There is also Condensed Remediation Plan for Small Microbial by Greg Weatherman. I haven’t really written much about this subject but plan to eventually. It’s a big subject.

      Ideally, you’d clean items using KCT QUAT. Carpets and any porous furnitute or materials from moldy buildings that can not be run through the washing machine or otherwise seriously washed using Borax can not be kept.

      By “black mold” I’m thinking you mean Stachybotrys. The reason I say this is that any given mold can have a range of colors. As such, color alone is not the best indicator. I’m sure you probably already knew this but there may be others that weren’t aware. Regardless of the type of mold, the protocol is the same.

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