What’s that funny smell?
Share
Mold and mildew in auto air conditioning systems is not often thought of as a problem in today’s automobiles. Air conditioning in automobiles has been around since the 1940s, and it is now a standard feature on any new vehicle. As well, today’s climate control systems are designed to eliminate or keep to a minimum chances of pollen, dust and other debris from getting into the automobile’s passenger cabin. Some independent service providers will say they have not seen a problem with mold or mildew in ages, or at least have not had anyone come into their shops to report a problem with mold or mildew. They might say the problem was once more common in older vehicles, those from the 70s or early 80s when air conditioning was expensive add-on feature on automobiles, and the air conditioning systems back then were not designed to effectively prevent debris and mold from getting into the system and gumming up the works.
But just because mold and mildew is not often reported on today’s newer vehicles, that does not mean the problem has gone away.
“When I took a look at some of my invoices (from last year), our shop has over 70 invoices that were specifically to do with smell and molds,” said Gerry Lecavalier, owner of Rad Runner and Auto Aces Inc. Warehousing in Ottawa. Lecavalier’s Rad Runner operations specializes in air conditioning maintenance and repair
Where is that smell coming from?
The first sign that there might be a problem with mold or mildew is noticing a funny smell coming out of the heating and cooling vents when the air conditioning system is turned on.
Steve Perusits, owner of Wally Clayson/Master Mechanic in Toronto said the smell can range from a slight musky smell, like what a person smells when leaves have started to decay, to sometimes a much stronger smell, closer to the smell one gets from an old gym bag filled with sweaty clothing and sports equipment.
The way mold and mildew grow inside an automobile’s air conditioning system is there is an excess of moisture in the system. That excess moisture can happen in two ways. The first is the vehicle has been improperly stored and there has been some sort of water leakage, providing an environment for mold and mildew to grow. The more common way for mold and mildew to get a foothold is for excess moisture having built up inside the evaporator core which sits inside a box. This evaporator core and its box are located under the dash of the automobile. The evaporator core’s job is to create the cold air that is sent into the vehicle when the air conditioning system is turned on. The air conditioning system draws air from the outside, cools it down with the evaporator core and sends the cooled air inside the car. As the evaporator core does its job, moisture is produced which normally drains away through a hose, which is what produces that puddle by the vehicle when it is sitting still and the air conditioning is running.
But if that water cannot drain properly and sits stagnant for long periods of time inside the evaporator core and its box, that water now pooling inside that dark, cool place can become an ideal environment for mold and mildew for grow. Research has found that such fungi as Aspergillus, Cladesporium, Penicillium and others can get onto the cooling coils and other air conditioning system areas and grow if the conditions are right.
Perusits said the amount of water that can build up inside a clogged evaporator core box, and which can provide an excellent environment for such fungi and molds to grow, can be significant.
“I’ve filled almost a litre container with (excess) water because the (hose) had gotten plugged up,” said Perusits.
Perusits added the evaporator core getting gummed and preventing proper water evacuation was often a common problem in older vehicles where the air intakes, unlike in many of today’s vehicles, lacked a protective screen to prevent leaves and other debris from falling into the air intake hoses and then getting into the evaporator core. Over time, this accumulated debris blocked the hose that is supposed to take the excess water out of the evaporator core, and instead let the water accumulate, thereby providing the environment for the mold and mildew to grow.
Perusits said technicians, whenever they have an automobile up in a hoist, should take a quick minute to examine the evaporator drain hose and see if it is clogged and to remove any debris that may be there. That is the first step in any air conditioning maintenance program and for tackling the problem of mold and mildew.
Also, mold and mildew problems tend to be more common in environments where there is a lot of heat and humidity. For example, issues of mold and mildew are more common on the East and West Coast of Canada where there is a lot of humidity, and in Southern Ontario which during the summer months often takes a double punch of not only very hot temperatures but also humidity. It is less common in the Prairies where the weather is much dryer.
Lecavalier said that with this year’s early warm weather he has already had three vehicles in his shop with complaints from their owners of odours coming from the air conditioning systems caused by mold.
Low airflow coming from A/C system could spell trouble
But if there is no odour coming from the air conditioning system that does not mean there may not be a problem.
Jim Kerr, an instructor in the Automotive Service Technician program with the Saskatchewan Institute of Applied Science and Technology in Saskatoon, Sask. said a tip-off that there may be a problem with mold or mildew is a decrease in airflow from the air conditioning system.
“A customer will come into a shop and complain they have poor cooling in the car,” Kerr said. “That is because the mold has created a barrier to the airflow in the evaporator unit. When that happens, the air that does come out (of the vents) is cold, but the air does not enough airflow or capacity to cool the inside of the vehicle.”
Kerr suggested technician first do a performance test on the air conditioning system to make sure the system is fully charged and it is mechanically sound. Then the technician should check to make sure all the electrical systems are working well, and that there are no leaks that could be causing the decreased air flow.
Reno Farrugia, climate product manager for the North American Aftermarket with Visteon Corp. in Van Buren Township, Mich. said once the mechanicals check out alright, a technician should then move to checking the cabin/pollen air filter. This filter is similar to an engine air filter and is mounted up in the cowl area over the fresh air inlet and is designed to filter out pollen and dust.
“This filter gets neglected allot because it is mainly found on high-end vehicles,” said Farrugia. “If you notice low airflow coming out of the dash in high blower mode and can hear the blower motor struggling to blow out air that is a good indication that you have a dirty cabin air filter.”
But if the cabin air filter checks out fine or is replaced and there still remains a problem with low or restricted air flow, then it is time to carefully look at the evaporator core.
The first step would be for the technician to remove the blower motor as the blower motor resides in front of the evaporator core. Its job is to take the outside air and move that air over the core. By removing the motor, the technician should have a decent view inside the core and to see if there is mold, mildew or other debris inside the evaporator core.
If the technician discovers there is mold and mildew in the evaporator core, then steps have to be taken to get the mold and mildew out of the core. Farrugia said the first step is to make sure the drain and hose in the evaporator case is clear as the next step will be to use an evaporator cleaner and a technician must make sure the drain and hose are unobstructed in order to flush out the chemicals that will be used.
There are several companies that make evaporator cleaners which are designed to remove mold or anything that forms on an evaporator core. Several OEMs have approved such cleaners and have issued TSBs on their use to cover the problem of mold and mildew. Visteon recommends the Cooling Coil Coating product from Marietta, Ga.-based AirSept Inc.
When using AirSept’s product, Farrugia said technicians should follow a two-step process.
“You remove the blower motor to gain access to the evaporator core and apply the cleaner to the evaporator core surface,” he continued. “Then you reinstall the blower motor and run it to dry off any cleaner residue from the evaporator core. You then remove the blower motor once more and you apply a treatment that coats the evaporator core and core seals inside the case. You let that treatment soak in there for some 10-15 minutes and rinse the coating off with fresh water. After rinsing the coating off you will reinstall the blower motor and run it again so you get the evaporator core completely dry.”
Tom Brown, a professor with the climate control department with Centennial College in Toronto said a technician has to remember to get any cleaning foam or solvent to penetrate the whole surface of the evaporator core so that it can break up the mold and other debris that has gotten into the core.
“By cleaning the fins on the evaporator, not only do you improve or eliminate the odour that people encounter, but you can also help improve the cabin temperature as the evaporator will now be much more efficient,” Brown added. “You can get up to a two-degree Celsius drop in temperature when the evaporator is cleaned properly.”
Kerr often reminds technicians and his students that whenever using any kind of chemical in the evaporator core that they make sure the vehicle is properly ventilated both during the procedure and after.
“Some of the chemicals are very strong and the car has to sit for a length of time, a whole day in some cases, before the car in driven,” he suggested.
In some cases, if the problem is not to severe or the smell too bad, a simple can of Lysol can work just as well. It’s what Perusits uses sometimes. He takes a can of Lysol and sprays it into the clean air vents of a vehicle that has is fan running at full speed. This will take the Lysol through the entire air conditioning system and will get a most mold and mildew.
Mark Pereira, A/C product manager with Spectra Premium Industries Inc. in Boucherville, Que. added technicians should also regularly replace all cabin air filters, following the automobile’s recommended replacement schedule. Regular replacement of the filters can prevent airflow restriction and also prevent any debris from migrating down into the system and possibly causing a problem.
Lecavalier said while many automobile owners often don’t think about the air conditioning system, an independent service provider can be helpful in raising awareness of properly maintaining the system. He encourages shop technicians to ask people questions, such as are they noticing any funny smells or have they noticed any decreased airflow, or does the blower motor sound as if it is having to run more aggressively to blow air through the cabin. While some vehicle owners might think the technician is fishing for extra work, many more will be grateful that a technician has taken the time to ask and will likely say they have noticed some problem which needs to be looked at and fixed.
This, in the end, is extra revenue for the shop owner and a satisfied customer who will drive away breathing a little easier.
Simple A/C Maintenance Steps
Do a performance check to make sure the air conditioning system is working well.
Visually check to make sure there are no leaks in the system.
Check the fittings, hoses and components. Use an electronic leak detector to make sure that there are not any leaks that are not readily visible.
Check all cabin air filters and replace according to the manufacturer’s specification or on visual inspection if the filters are clogged.
Check the water drain hose to make sure it is not blocked and water can flow freely through it.
Tips for Avoiding Refrigerant Contamination
The old motto “Be Prepared” couldn’t be more appropriate for this coming A/C season. With rising refrigerant cost and contamination issues at the top of the list, what you do before you start an A/C service will make the difference between a successful business and a bust.
Start every A/C Service Order with these steps:
* Talk to the customer and understand the compliant
* Diagnose the problem
* Look for signs that they tried to fix it themselves
* Test for sealant
* Identify the refrigerant in the system
Leaky systems are often the main cause of poor cooling performance. So check for sealant. Many refrigerants available at retail stores are formulated with sealant to help to stop the leak. DIYers are likely to use these products, and they can ruin your recovery equipment.
Next, check the refrigerant with an SAE certified refrigerant identifier. It not only verifies the type and purity of the refrigerant, but also tells you how much air is in the system. Today’s A/C systems leave very little room for error and just two per cent of air can result in poor cooling performance. Verifying refrigerant purity can help avoid contamination of your shop’s 134a supply and potential loss of warranty on your recovery equipment.
Finally, be on the lookout for bad refrigerant. The high price or R134a has opened the door for counterfeit product from Asia and elsewhere as well as risky 134a mixtures. Buy your refrigerant from a reputable source always test it before you use it. For more information visit www.refrigerantid.com
Peter Coll is the National Sales Manager for Neutronics Refrigerant Analysis, a designer and manufacturer of advanced refrigerant analysis instrumentation the pioneer of of infrared measurement technology used to identify the type of refrigerant in A/C systems.
What Works To Reduce A/C Odour?
Some odour treatments are merely feeble attempts to cover up odour. Many odour treatment products fail to provide a long-term residual effect that can reduce the reoccurrence of odour. Below is a brief description of the performance capabilities of various odour treatments by product type.
Perfumes/Fragrances: Designed to cover up odour with a more acceptable scent. Cover-up perfumes and fragrances cannot eliminate odour-causing microorganisms.
Disinfectants: Destroy odour-causing microorganisms on contact. The typical liquid disinfectant quickly evaporates or washes out of the system. As airborne bacteria re-enters the system, odour can begin again. To control odour over time, disinfectants can require frequent repeat application.
Air Filters: Catch and absorb particulates and some gases as they pass through ducts to the passenger compartment. Many filters use activated charcoal. Filters become saturated or their active ingredient loses effectiveness over time, and must be replaced. Filters do not eliminate the source of odour-causing microorganisms.
Foam Cleaners: Use sudsing action to push dirt out of the evaporator through the drain tube. Includes disinfectant to kill microorganisms on contact. Quickly evaporates or drains from the system. Offers no long term odour protection.
Chemical Reactants: Reduce odour by combining with molecules of the odour-causing microorganism. The new, combined molecules must then be removed (wiped up with a dry towel, washed away in a liquid, etc.) to complete the odour treatment. Like liquid disinfectants and foam cleaners, chemical reactants provide only a short-term treatment, and can allow odours to return quickly.
Antimicrobial agents: Have a wide range of successful microbial control applications, from inhibiting fungal growth on boat hulls to preventing mold and mildew growth in carpet and wall coverings. Can quickly drain from the evaporator along with condensation.
Cooling Coil Coating: Combines a powerful formula with an acrylic resin that covers evaporator surfaces with a long-lasting coating. The coating does not wash out of the evaporator for up to three years.
The product formula and coating combine to inhibit the growth of any microorganisms that settle on the coated surface for the life of the coating.
Electronic Evaporator Dryers: Electronically-controlled system cycles the blower motor on and off after A/C shutdown, pushing odour-causing moisture out of A/C evaporators. Newer evaporator dryer technology automatically senses whether the blower circuit is positively or negatively switched.
Installation is the same whether the blower switch and resistor are on the power feed or ground side of the circuit. This simplifies installation and reduces the part numbers to stock. It works on any 12-volt blower motor system.
This new electronic evaporator dryer technology also pulses the fan instead of running it continuously. Pulsing removes more water in a given amount of time, and saves battery power.
Other battery-saving features include sensors that deactivate the module when ambient temperature is below 60 F (too cool for microbial growth) or shut it down if the circuit shows less than 12.5 volts.
When used together, cooling coil coating and the new electronic evaporator dryer technology result in extended protection against A/C odour.
Information provided by AirSept, Inc.
Reference List:
AirSept Inc.
Auto Aces Inc. Warehousing and Rad Runner
Centennial College
http://www.centennialcollege.ca/
Saskatchewan Institute of Applied Science and Technology
Spectra Premium Industries Inc.
Visteon Corp.
Wally Clayson/Master Mechanic
Leave a Reply