Brand new car started emitting a foul musty smell with AC on after 800 miles. I live in AZ desert where the Air is very hot & dry so, there is definitely a problem with the factory installed AC system. I've worked on cars my whole life and have some experience with AC systems, but I'm no AC tech and not licensed to do so, just have a little background knowledge and friends who are licensed. Here's the problem & solution:
PROBLEM: Normal for an AC system to develop condensation which is caused by the evaporator in the dash becoming very cold from the compressed refrigerant, and when the hot/warm air from the inside of your car gets blown onto the evaporator by the cars fan, the reaction of ice cold evaporator and warm air coming into contact with each other causes condensation. This is what you see puddling under your car with he AC on. It's doing it's job when you see the water dripping out.
If there is poor drainage from the evaporator such as a kinked hose, clogged hose, poor drainage design, improperly installed padding around the evaporator restricting drainage, or even a dirty cabin air filter which will cause restricted air flow to blow on the evaporator, then you will get a foul musty smell.
The automatic climate control system in the 2016 Honda Accord by default will set itself into RECIRCULATE MODE which means the car is recirculating air that is inside your cabin. You are not getting fish air from outside, therefore all the humid musty air trapped in the dash is not getting out when you shut off the car.
SOLUTION: Always take your car to the dealer under warranty such as what I am doing to have them take a look and investigate the concern.
SELF/TEMPORARY or POTENTIALLY PERMANENT FIX:
1. If you like to run the car in auto climate mode, then just remember 5-10 minutes from reaching your destination, turn the recirculate mode off, which will allow fresh air to enter the system, turn the AC system off, run the fan on high with dash vents all open to dry up the evaporator. This will provide excellent results, significantly reduce the smell, and probably make your AC system last longer. You won't have that funky smell in the morning or next time you start the car and run the AC.
2. You can turn off recirculate mode every time you get into the car which allows fresh air to enter continuously, but you still need to turn the AC off, run fan 5-10 minutes on high to dry up the evaporator before reaching your destination and shutting off your car.
3. If you don't run the fan 5-10 minutes to dry the evaporator, then the moisture sitting inside your dash overnight or several days becomes moldy, and over time from restriction of airflow and not being able to escape, you get the horrible awful smell. Your car will still keep you cool in that 5-10 minutes without the AC on. I live in AZ where it gets 120 degrees and it works for me.
4. Don't allow anyone to spray aerosol deodorant sprays into the vents or evaporator, the chemicals from the spray can melt certain rubber seals inside the dash and deterirate foam padding. Don't spray anything, just run the fan, and put in a fresh air filter.
5. Change the air filter every 6 months or 6,000 miles in dusty climates. When the filter gets restricted, the airflow decreases which means there's not a lot of air volume moving across that evaporator that is all wet. it's all about keeping the evaporator dry when in use, not in use, and keeping good airflow.
Update from Jun 5, 2019: AC still smells at 25,210 miles and after 3 years of ownership.
Update from Feb 4, 2020: I shut the AC off and run the fan on high when I know I'm about 5 minutes from home or my destination. This gets the evaporator to a room temperature while driving and drys the water off the evaporator. By doing this, eliminating the moisture prevents any fungus, mold, or bacteria from being able to grow on a damp surface which causes a musty smell. Changing cabin filter twice a year, every 6 months also helps or once before summer and once before winter really helps keep the HVAC system clean and prevent smells.
Now I am seeing dust collecting to oil on the high and low pressure pipes that insert into the firewall that connect to the evaporator. I believe there is a leak and possibly the AC may have been overcharged from the factory which can cause seals to blow out.
A D V E R T I S E M E N T S
Brand new car started emitting a foul musty smell with AC on after 800 miles. I live in AZ desert where the Air is very hot & dry so, there is definitely a problem with the factory installed AC system. I've worked on cars my whole life and have some experience with AC systems, but I'm no AC tech and not licensed to do so, just have a little background knowledge and friends who are licensed. Here's the problem & solution:
PROBLEM: Normal for an AC system to develop condensation which is caused by the evaporator in the dash becoming very cold from the compressed refrigerant, and when the hot/warm air from the inside of your car gets blown onto the evaporator by the cars fan, the reaction of ice cold evaporator and warm air coming into contact with each other causes condensation. This is what you see puddling under your car with he AC on. It's doing it's job when you see the water dripping out.
If there is poor drainage from the evaporator such as a kinked hose, clogged hose, poor drainage design, improperly installed padding around the evaporator restricting drainage, or even a dirty cabin air filter which will cause restricted air flow to blow on the evaporator, then you will get a foul musty smell.
The automatic climate control system in the 2016 Honda Accord by default will set itself into RECIRCULATE MODE which means the car is recirculating air that is inside your cabin. You are not getting fish air from outside, therefore all the humid musty air trapped in the dash is not getting out when you shut off the car.
SOLUTION: Always take your car to the dealer under warranty such as what I am doing to have them take a look and investigate the concern.
SELF/TEMPORARY or POTENTIALLY PERMANENT FIX: 1. If you like to run the car in auto climate mode, then just remember 5-10 minutes from reaching your destination, turn the recirculate mode off, which will allow fresh air to enter the system, turn the AC system off, run the fan on high with dash vents all open to dry up the evaporator. This will provide excellent results, significantly reduce the smell, and probably make your AC system last longer. You won't have that funky smell in the morning or next time you start the car and run the AC.
2. You can turn off recirculate mode every time you get into the car which allows fresh air to enter continuously, but you still need to turn the AC off, run fan 5-10 minutes on high to dry up the evaporator before reaching your destination and shutting off your car.
3. If you don't run the fan 5-10 minutes to dry the evaporator, then the moisture sitting inside your dash overnight or several days becomes moldy, and over time from restriction of airflow and not being able to escape, you get the horrible awful smell. Your car will still keep you cool in that 5-10 minutes without the AC on. I live in AZ where it gets 120 degrees and it works for me.
4. Don't allow anyone to spray aerosol deodorant sprays into the vents or evaporator, the chemicals from the spray can melt certain rubber seals inside the dash and deterirate foam padding. Don't spray anything, just run the fan, and put in a fresh air filter.
5. Change the air filter every 6 months or 6,000 miles in dusty climates. When the filter gets restricted, the airflow decreases which means there's not a lot of air volume moving across that evaporator that is all wet. it's all about keeping the evaporator dry when in use, not in use, and keeping good airflow.
Update from Jun 5, 2019: AC still smells at 25,210 miles and after 3 years of ownership.
Update from Feb 4, 2020: I shut the AC off and run the fan on high when I know I'm about 5 minutes from home or my destination. This gets the evaporator to a room temperature while driving and drys the water off the evaporator. By doing this, eliminating the moisture prevents any fungus, mold, or bacteria from being able to grow on a damp surface which causes a musty smell. Changing cabin filter twice a year, every 6 months also helps or once before summer and once before winter really helps keep the HVAC system clean and prevent smells.
Now I am seeing dust collecting to oil on the high and low pressure pipes that insert into the firewall that connect to the evaporator. I believe there is a leak and possibly the AC may have been overcharged from the factory which can cause seals to blow out.
- monty4169rm, Phoenix, AZ, US