That Vexing Vapor Venting (Vapor Coming out of Vents)
May 19, 2024
You may have noticed sometimes on a hot and humid day, vapor will come out of your vehicle's vents when you have the air conditioning on. Is that something to be concerned about? Well, it depends.
Sometimes that steam or vapor can be caused by water accumulating in the vent system after it has condensed. And sometimes water can pool at the bottom of a vent. When you turn on the blower mower, the air hits the water and may create steam or vapor that you can see in the cabin.
One thing to check is if that vapor smells like anything. If it doesn't, that's a good sign. You may be able to run the fan for a while and the issue may just go away when things dry out. But moisture collecting in the ventilation hoses in a hot vehicle may be a breeding ground for mold, and that can have health consequences.
There's another possibility. Ventilation systems often have drains to get rid of any accumulated water, and debris can sometimes clog them. A technician can clean out those drains and you'll be back in business.
One thing to nose around for is a sweet smell coming out of your vents. Sometimes the heater core (a component of your vehicle's heater system) can develop very tiny holes. That sweet smell may be coolant that's been vaporized by those tiny holes entering your cabin.
It's always a good thing to mention to your service advisor any abnormality you're seeing—or smelling—in your vehicle. By venting a little about your vents, a technician can get to the bottom of the problem before it starts "clouding" the issue.
Commerce Auto Repair
9575 Commerce Rd.
Commerce, Michigan 48382
248.363.3749
Need Service?
More articles from Commerce Auto Repair

T for Transmission, T for Trouble (Automatic Transmission Trouble Signs)
April 15, 2026
One of the hardest working components of your vehicle is its transmission, shifting gears up and down when you need it to. The transmission is vital to your vehicle driving properly, and if you start to see signs of problems in it, its best to have them fixed earlier rather than later. (Since ne... More

Smooth Operator (Shock Absorbers)
April 14, 2026
When you are comfortably headed down the road, you may not realize how many of the imperfections in the driving surface are being smoothed out, so you hardly feel most of them. You can thank your shock absorbers for a lot of that comfort, and its important to make sure you keep your shocks in go... More

Go with the Flow (MAF Sensor Replacement)
March 29, 2026
If your vehicle has an internal combustion engine, it depends on two things to make propulsion power for you to be able to motor on down the road: fuel and air. The engine mixes the two in just the right proportion so that they can be ignited, creating a series of tiny explosions that are coordi... More
