Why does my car’s air conditioner smell?

In this series of Q&A posts, we are using google’s autocomplete function to find the most commonly asked questions about cars and giving them each a definitive answer. This series is ongoing and you can find more of our Q&A articles right here.

Why does my vehicle’s air conditioner smell so bad?

What you are probably smelling is mildew and it is a surprisingly common problem.  When your A/C is in operation its evaporator core develops frost as a natural byproduct of its function. When you turn your vehicle off, it melts, and any small amount of standing water can be an inviting place for mildew or fungus to accumulate.

If you are a DIY type and feel like doing a bit of detailing there are products that can be sprayed into the system to kill the mildew and neutralize the odour. These products come as an aerosol spray and need to be sprayed into all of the air intake vents in the cowl area of the vehicle.  It is a bit of work to take the cowling apart but it can be done if you are mechanically inclined. Here are the steps for our Do-It-Yourselfers:

1. Start Vehicle and put the A/C fan on high
2. Double check that recirculation mode is OFF
3. Open all windows
4. Spray product liberally through all intake vents in the cowl area
5. Switch climate control to heat and spray again in the same place
6. Let the A/C run for a few minutes to circulate the remaining aerosol.

Not feeling so adventurous?

Just give us a call and we can sort it out for you, or mention it at your next regularly scheduled maintenance and we can inspect your A/C unit as part of our regular inspection.