What Causes a Bad Smell from a Car Air Conditioner?

There is nothing worse than driving on a hot day and turning on your car air conditioner to discover an unpleasant smell. Many people tend to accept this as just what happens to car air conditioners over time, and do not realise that it can often be easily, and cheaply fixed. Car air conditioners are not supposed to smell bad. If they are clean and working properly, they should not emit an odour at all. So, what causes a bad smell from a car air conditioner?

Possible Sources

A generally bad smell from a car air conditioner is most commonly caused by mold and bacteria. Over time, mold can grow and build up in your vents, which causes an unpleasant smell when you turn it on. As your car ages, bacteria, fungi, and micro-organisms will also start to grow, which worsens the smell. These usually grow behind the dash panel on the evaporator. Another common cause is build up of dirt, dust mites, and stagnant water in your car’s air filter. This can happen over time if the filters are not regularly, and properly cleaned.

Sometimes your car air conditioner may produce a more distinct smell, which can help you pin down the cause even more quickly. For example, if you smell gas whenever you turn your system on, it is likely your car has a gas leak. If the smell is sweet, however, this means you are leaking antifreeze, which is a highly toxic chemical and indicates you have a leak in your cooling system. 

How do you get rid of the smell from your car air conditioner?

Nobody likes having to put up with unpleasant smells, but luckily there are things you can do to fix the problem. The method will of course depend on the cause of the smell, and you will need to keep two stages in mind; cause and symptom. To properly fix the smell issue, you need to address both of these.

If your car smells bad due to mold, fungi, bacteria, and micro-organisms in your vents, you will need to give them a thorough clean. If the issue is dirt, dust mites, or stagnant water in your air filter, replacement is your best course of action. By the time an air filter reaches the stage of smelling bad, cleaning it is not likely to fix the problem.

If the smell is due to a leak, such as gas or antifreeze, the only way you can get rid of it is to get the leak fixed and then thoroughly clean your air conditioning unit to remove any residual odors.

Do you need to use expensive chemicals to clean your car air conditioner?

There are many cleaning solutions on the market for your car air conditioner, but if you do not want to spend a lot of money, or if you prefer not to use chemicals, there are other options. Vinegar and water solutions can be very effective cleaners and are something you can easily make in the home. Some people also use bleach and water solutions. It all comes down to your personal preference.

Can you prevent your car air conditioner becoming smelly?

While smells occurring in car air conditioners are unavoidable over time, being inevitable as your car ages, there are things you can do to delay this occurring. Avoiding turning your air conditioner on to full is one way. This makes it less likely to drip water, and dripping water inside the unit promotes the growth of mold and bacteria. Likewise, ensuring you drive your car regularly, and switching the unit on every so often outside of the summer months, can also slow the potential growth of mold, bacteria and other microorganisms.

Keeping your car clean, regularly serviced, and checking for leaks is another way to prevent unwanted air conditioner smells. Changing air filters regularly, and ensuring any leaks are fixed quickly, will also help you avoid unpleasant odors when using your car air conditioner.