Why Does My Car A/C Smell Like Pee [and How to Solve it]?

dr Drashco
dr Drashco Cars

In this post I'll explain how to turn your car that smells like fish, mold or pee into a pharmacy smell fast (in 60 minutes or less).

The truth is, nothing is more annoying than a sudden mold, fish or urine like smell overwhelming the cabin almost instantly upon starting your car and turning the a/c on.

But do not worry, this is one of the easiest car problems I have ever solved.

So if your question is, "why does my car a/c smell like pee?" it's your lucky day as I am going to explain how to deal with this issue, step by step.

First, let's see why the car a/c smells like pee, then I'll show you how to get rid of this unpleasant urine-type smell, and finally - how to prevent it from happening in the future.

Let's dive right in.

In This Guide, You'll Learn:

Why Does My Car Air Conditioner Smell Like Pee?

Does your vehicle a/c smell sort of like urine and mold combined, especially when you enter the car and turn it on? If so, you have to know it's a widespread problem. This can be not very pleasant in Texas or Arizona because many people use the a/c every day.

When the car A/C is turned on, the smell usually goes away after a few minutes. However, in some extreme situations, it will go away only after a long trip, with the A/C turned on all the time.

The root causes are bacteria and mold. Inside your vehicle's air conditioning system is an "evaporator" designed to cool the air by removing the heat and moisture from your vehicle's interior (when the A/C is turned on). Even when the air is pretty dry, there's still enough moisture to condense upon the evaporator.

Condensed moisture on the evaporator is supposed to drip drain away. However, the drain will often become clogged, and it won't drain quickly enough. Suppose that water can stagnate inside the evaporator unit. In that case, this water grows mold and bacteria and eventually causes your vehicle's air conditioning system to smell — especially after the system is first turned on.

How to Get Rid of Urine like Smell on Any Car A/C?

There are only three ways to fix this [spoiler alert - no. 3 is my favorite].

How to fix the pee like smell from the car a/c
  1. Give the evaporator, air vents, and ducts a thorough cleaning. Of course, you would have to disassemble and remove those parts from your car first and then re-install. As you can imagine, a lot of work is involved here, so it's your last choice. The good news is that this shouldn't be necessary in all but the most extreme cases. However, this may be your only option if the car (with a bad a/c odor) stays parked for a prolonged period or if you ignore the smell long enough.
  2. Clean the Air Conditioner using the specialized chemical. There are a lot of them on the market, advertised to neutralize any bacteria or mold growing inside your vehicle's a/c system. You can also try a DIY solution – sometimes, spraying an odor neutralizer into the air vents can help.
  3. [My favorite method - it will make you feel like a superhero!] Replace the cabin filter and then pump the car cabin with an ozone generator while the a/c is running. Ozone will enter every pore and react with anything and everything alive that inhabits your ventilation system!

High concentrations of ozone in the air (when people and animals are not present) can be effectively used to decontaminate an unoccupied space from specific biological contaminants, chemicals, or odors.

After successful decontamination of your car a/c and ventilation system with ozone, instead of a smell like pee, you will have a strong, pharmacy-like smell in the car for at least another 3-7 days.

Ensure to reach high enough OZONE (O3) concentration in the car by letting the ozone generator run for at least 10 minutes, with windows closed and internal air recirculation on. O3 will quickly enter any vent, duct, or fabric.

WARNING: Ozone is very toxic in high concentrations, and can harm your health. Use it at your own risk! You can read more about the Ozone precautions at the EPA.gov website.

Do not do try this in a garage or any closed space. Perform this activity strictly when the car is outside. After disconnecting the OZONE generator, make sure not to enter the vehicle for at least another 30 minutes, letting the ozone settle down a bit. Then, open the door, trunk and windows for at least another 30 minutes, to let the fresh air into the car and ozone out.

Please try not to use this method often or as a preventive, but only if you already have a car a/c smelling like pee.

How to Prevent Your Car A/C from Smelling like Pee?

There is a method to prevent mold and bacteria from growing in the first place.

Simply turn off your air conditioning five minutes before you stop driving. Then turn on your interior fan to full speed – you'll help dry out your vehicle's A/C system. Just five minutes on a fan (without using the A/C) before you shut your car off will make a huge difference.