Does your car have foul smell?

If your car smells like mildew or has foul smell when you turn on the air conditioning, you could potentially have fungus growth on the air conditioning (AC) component called the evaporator.

Your car's AC system has an evaporator that is located underneath the dashboard. It is usually hidden behind the passenger's glove compartment. The job of the evaporator is to remove hot and humid air and turn it into dry cool air.

The evaporator is enclosed in a dark box where moisture could still be present long after you've turned off the AC. Once the AC is turned off there won't be any circulated fresh air to dry off the evaporator. Overtime, the moisture that gets collected in the evaporator could be very problematic.

Th problem occurs when a dark and damp condition persists over time. This dark and moist environment is a perfect place for smelly bacteria to grow. When smelly bacteria started to grow, you could only expect mildew or foul smell to blow out every time you turn on your AC.

What could make matter worse is if your evaporator system has a semi or plugged drainage hose (which was designed to drained out the condensation created by the AC evaporator) water could leak into the interior of your car causing double the smelly trouble.

Here are some pictures of new and old evaporator cores:

Evaporator enclosure: The evaporator box is usually located behind the passenger's glove compartment.

New Evaporator Core: Evaporator cores are made out of many folds of aluminum fins. These fins get cold and damp under normal operation. The cold and damp fins tense to collect tiny dust, debris and anything else that may get in contact.

Old Evaporator Core: Over the life of an evaporator core many particles get collected.

Extremely Dirty and Unhealthy Evaporator Core: Here is an extreme case of where the the aluminum fins are no longer effective. The fins are fully covered with unhealthy "STUFFS". Chances are, fungus could also be found in this example.

What You Could Do

• If your car has a cabin air filter, change it as soon as you can.
• Turn off your AC a few miles before you reach your destination AND leave the fan running to dry off the evaporator.
• Some people like to freshen up their cars by using Lysol to spray through the ventilation opening with the fan running on fresh air circulation mode. The opening is usually located at the bottom of the windshield.
• There are products out there that you could try besides Lysol, but don't buy the types that only mask the smell.
• The most expensive (maybe not feasible to most people) step you could do is to replace the evaporator.