'Hi....My 04 Sonata has a mouldy rotty type of smell when I first start
it,.....after the AC has been on for a short time, the smell goes
away....Is it maybe mildew or something in the air system? What can be
done besides just masking it with an air-freshener?'
REPLY: I am in the HVAC Trade, but not automotive .. Im in residential
and commercial. However, the problem is prevalent in both sectors.
Heres some food for thought on ridding/greatly reducing what we call
'the smelly socks' syndrome associated with A/C's :
1. When you are using your cars A/C and getting near to your
destination, shut off the A/C but allow the blower to continue to run .
This will evaporate the condensate that has condensed on the surface of
the evaporator and reduce the smell buildup. Shut off your A/C at least
3 minutes before youre reading to shutoff your engine.
2. If you remove your cabin air filter, you will have direct access to
the incoming-air side of the evaporator ; it will be a shiny grey metal
object approx. 6" square to the left of the air filter slot. You will
only have access to the one side, but, that is better than nothing.
Spray some non diluted vinegar on the fins / tubes of the evaporator
surface in addition to the plastic condensate pan directly under the
evaporator... and allow it to sit there for at least 20 minutes before
using the A/C again. Vinegar does a good job of eliminating this
particular smell and will not harm the Evaporator or affect its
operation. There is no need to rinse the vinegar off as the next time
you use the A/C, the condensate will wash off any residue. Initially,
you will have a strong odor of vinegar, but it will dissipate in no
time. You should be able to go a fairly long time after a treatment.
3. At hardware stores, they sell a small stick-on fragranced 'thing'
(cardboard) in various scents that you can apply to your cabin air
filter ; this will dilute the evaporator smell and make the cars
interior smell nice also. Its not very big so it wont restrict airflow
thru the air filter . It lasts a fairly long time before you can now
longer smell it. Again initially, it is a bit strong but does dilute
4. There is a product called Febreze available at Grocery Stores which
is pretty good ; you can spray that down the supply air outlets of your
car with the Blower off and/or , into the return air cavity of the
Blower Assembly located behind your glove box while the Blower is
running. Spraying it in the general vicinity behind the glove box is
all thats required as it will get immediately sucked into the blower
then thru the evaporator and ducting system. It comes in various
fragrances and lasts awhile.