Smells and allergies

There can be many sources of a smell inside your vehicle
You can avoid smells, or remove the source.

Now that winter is over, perhaps you’ve noticed some unpleasant smells inside your vehicle. Or you may notice your allergy symptoms on the rise.

The smells may have been sneaking up on you over the past few months. They usually originate from something spilled or left in the vehicle. The allergy issue is likely odourless, something in the air brought into the interior through the ventilation system.

In either case, the first order or business is to locate and eliminate the source.

First things first – the cabin air filter.

Also known as a pollen filter, air-conditioning filter, passenger compartment air filter, interior ventilation filter or dust filter. Their sole purpose is to prevent environmental contaminants like pollen, dust and soot from getting into the interior of the vehicle. These can aggravate seasonal allergies, asthma and other respiratory conditions,

Over time they become clogged and ineffective, more quickly if you drive in dusty and/or dry conditions. Most manufacturers recommend checking and replacing the cabin filter every year or 15,000 kilometres or so. Check your owner’s manual to see if your vehicle has one. You may be able to replace it yourself, or in some cases it may take a technician an hour to do so because other components will have to be removed to get at it.

While on the topic of insidious causes of odours, become familiar with the recirculate switch on your HVAC system. Most vehicles have them, identified by an arrow turning back on itself. The purpose is to recirculate the air in the interior for the first few minutes when warming it up in the winter or cooling it down in summer.

But, if left in that position, blocking off fresh outside air, the re-circulated air will cause problems and a musky smell. Each time you breath, you remove more oxygen from the air and introduce more moisture. You can become drowsy and the added moisture will be deposited on the cold glass. Look around in the fall through spring season and you will notice vehicles with all windows fogged up. It is a good bet the HVAC system is in the recirculate mode.

But what if the problem is a foul odour and nothing to do with the filter or recirculation system?

Here we have two likely culprits – smoke or something spilled or left in the vehicle. The interior of your vehicle is a sealed environment. You have to find the source and clean it up as soon as possible before it permeates the entire vehicle getting into the upholstery and carpets.

I’ve experienced everything from a tiny mouse that decided to take up residence in the heating ducts, to spilled milk that found its way into the padded underlay beneath the floor carpets.

Start with a thorough vacuuming, reaching into and looking under all seats and floor mats. Do the same in the trunk or cargo area. If there has been a “liquid mishap” by a pet or child that has soaked into a seat or mat, it should be cleaned separately with proper upholstery cleaner. Spilled fluids are arguably the worst since they have the ability to flow and seek the lowest point – under the carpets, in the tiny cracks, crevices and into the padded underlay.

There are two approaches to cleaning tough smells – enzyme-based cleaners, which break down and “digest” odour-causing stains and ozone generators that react with odour molecules, destroying them.

Deodorizers and “air fresheners” do nothing more than hide the problem, allowing it to get worse.

Ozone generators are generally available at professional detail operations. Care in their use and operation is necessary as the ozone itself can cause respiratory problems. The vehicle has to be aired out and left unattended for several hours after the treatment.

If you aren’t willing to spend the money to have the ozone treatment, there are a variety of odour neutralizers on the market. Rather than hiding the smell, they chemically bond to odour molecules and prevent them from interacting with the receptors in your nasal passages. They come as a spray, or preferably as a fogger that gets into every nook and cranny. The fog approach is best for ridding the vehicle of smoke or odours from urine or the various glues, chemicals and sealants used during manufacture.

Whatever solution you use, the final step is to let your vehicle air out in a dry and preferably windy environment. Most cleaners are liquid-based and will remain damp inside a closed vehicle.

About Richard 166 Articles
At the age of five I was already obsessed with all things automotive being able to identify the make and model of car by just the sound of its engine going down the street in front of our house in the small town on the south shore of Nova Scotia. Although I have been covering and writing about the automotive scene for more than 40 years and the light still grows brightly.