Why Is My Car’s AC Blowing Vapor?

Why Is My Car’s AC Blowing Vapor?

Have you ever noticed a vapor or steam emanating from the vents of your vehicle while you’re running your air conditioning? This can cause a shock for some people who wonder if it’s smoke coming from a fire somewhere inside their car. However, there’s usually no cause for immediate alarm—as long as the vapor is odorless, it’s nothing you need to immediately worry about.

However, there are enough people who call in and ask about the steam coming from their vents while running the air conditioning that we figured it’s important to talk a bit about this phenomenon and what causes it. With that in mind, here is some info from a mechanic in Sarasota, FL about vapor in your car’s air conditioning system and the causes behind it.

The Cause

Vapor coming from the AC isn’t exactly a widespread problem, but it can certainly happen from time to time. It most frequently occurs during particularly warm and humid weather. Most mechanics agree that it’s nothing to worry about—it’s more of an inconvenience than anything.

The odorless steam that comes out of a vent could be excess water that builds up inside the heater box, which could indicate you need to clean the drain hole. The problem is especially common in older cars—there’s a possibility that there’s some sort of condensation building up in the ventilation systems, which are not as sophisticated in older vehicles, meaning steam can be easily created during hot and humid weather.

This only becomes particularly concerning if it starts to get an odor that smells stale or wet, which usually is a sign of mold or mildew.

The Solution

If the problem is related to a clogged drainage hole, then it’s an easy solution that shouldn’t be expensive to fix. You can typically unclog the hole within a half hour to 45 minutes.
You might also try running the fan continuously to see if the system dries itself out. But if you’re unable to resolve the issue yourself, it might be a good idea to mention the issue to your mechanic during your next appointment to see if it’s a sign of a larger problem.
The big issue to watch for is, again, whether there is any odor associated with the steam, or if it actually is smoke. If you have mold that’s forming inside your ventilation system, you’re going to want to get it fixed, just because mold spores can cause respiratory problems in people, especially those who are already prone to conditions such as asthma or allergies.
Again, this is rarely an issue that merits significant concern, but there’s no harm in asking your mechanic in Sarasota, FL to look into the issue if you’ve noticed it. Any time you have any sort of problem or unusual occurrence with your vehicle, we encourage you to reach out to Lowe’s Automotive Service, Inc. We’ll happy to give your vehicle a look and tell you what we find and what the best option is moving forward.