That Vexing Vapor Venting (Vapor Coming out of Vents)
August 2, 2020
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.
ABC Auto Works
127 E. Walled Lake Drive
Walled Lake, Michigan 48390
800-742-4511
Need Service?
More articles from ABC Auto Repair & Tire Center

A Smart Inspection, Peace of Mind Before You Buy
June 14, 2026
With the price of new vehicles these days, you might be thinking about saving some money by buying a used one. But when you go to look at a vehicle, how in the world do you know what youre getting into? A look around the outside and a short test drive likely doesnt give you the confidence that... More

The Untold Truth About Blinker Fluid: Why Your Car Desperately Needs It
May 10, 2026
If youve been ignoring your dashboard, your mechanic, and that one guy at the gas station who muttered bro your blinkers sound dry, then buckle up because today we dive into the critical world of blinker fluid maintenance. What Is Blinker Fluid? Blinker fluid is a high-viscosity, luminescent com... More

Mileage Headed Downhill? (What Causes Bad Fuel Economy?)
April 15, 2026
Name someone you know who enjoys spending a lot of money on gasoline. Yeah, me neither. Thats because it costs quite a bit to keep fueling your vehicle. One way to save money on gas is to get good fuel economy, and most of todays vehicles are designed to maximize your mileage. But you might f... More
