Back to all

That Vexing Vapor Venting (Vapor Coming out of Vents)

August 16, 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.

Tuffy Tire & Auto Service Center Lockport
600 E 9th Street
Lockport, Illinois 60441
815-838-3700

More articles from Tuffy Lockport

U and your U-Joints (Lubricate U-Joints)

June 9, 2025

If your vehicles power goes to the rear wheels, then you have something called U-joints in the drivetrain. U-joints are connectors that allow the rotating power from your vehicles engine to deliver its power through a driveshaft to make the rear wheels rotate. You need U-joints because the surfa... More

Don't be Fuelish (Signs Fuel Pump is Failing)

June 2, 2025

A driver of a large SUV loaded with equipment was heading on a 7-hour work trip when he stopped at a gas station to refuel. When he went to restart his SUV, it turned over but wouldn't catch. Try as he might, he was never able to get it started again. Of course there are many things that can c... More

When it Comes to Air Filters, Change is Good (Clogged Air Filter)

May 25, 2025

Engine air filters may not seem like a big deal, but when theyre clogged up with dirt, dust, and insects, your engine could wind up choking for air and not delivering you the power and performance it was designed to give. There are actually a couple of air filters in your vehicle. One filters th... More