Sometimes you may notice a little steam or vapor coming out of your vehicle's vents when running the air conditioning or heater. Is this something about which you need to worry?

The answer is it may or may not be troublesome. Sometimes it can be caused by water accumulating in the vent system after it condenses. That water can wind up at the bottom of a vent, and when you turn on the blower motor, it can cause what looks like steam or vapor to come out of the vents. 

It may go away on its own when the system dries out after you've run the fan for a while. Of course, moisture sitting around for more than a short time in a hot vehicle is the perfect breeding ground for mold to develop, and you don’t want your vehicle to smell like musty mold.

Sometimes the moisture can build up because a drain is clogged. A technician can clean that out and get things draining again.

If the vapor coming out of the vents has a sweet, syrupy smell, it could be caused by a hole in your heater core. The heater core is the part that helps heat the cabin in colder weather. The inside of your windows may even steam up if the hole is large enough.



In either case, if you have steam, smoke, or vapor coming out of your vents, bring your vehicle into your NAPA AutoCare Center as soon as possible so a technician can check it out. Catching a problem early on can potentially keep it from becoming bigger and more expensive to repair.