White Smoke from AC Vents: Understanding the Reasons

An issue with the engine or cooling system could be indicated by white smoke coming from the AC vent. Sometimes it might be located in the broken component of the air conditioning system. It warrants serious consideration regardless of the cause.

The white smoke coming out of the car’s air vents: what gives?

A variety of problems can be caused by smoke from an automobile’s air conditioning vent. The majority of them concern variables that might raise or lower the engine’s temperature. Things like coolant, damage, low oil levels, oil leaks, etc.
White smoke emerging from an automobile’s air conditioner vent could be due to a number of other things as well. Several things can lead to the issue of “smoke coming out of vents when AC is on,” as listed below.

Car getting too hot

An important part of the engine’s functioning is the cooling system. The engine overheats, a lot of hot air is drawn into the air conditioner, and condensation forms when there’s damage to the cooling system. White smoke will be expelled through the air conditioning vent as vapour if the heater box produces an excessive amount of moisture.

The engine is likely to overheat if you have been driving continuously without checking the coolant or water levels. A white cloud of smoke will billow from the air conditioner vent when the engine and other sections of the car begin to overheat.

The oil level is low

One of the main reasons your car becomes hot is because of the oil level. Imagine you’re the type of person who leaves the air conditioner on all the time without checking the oil level. If that’s the case, it’s likely that the internal components will get hot, which will cause hot air to enter the air conditioning system. Once there, the hot air will condense and go out of the vent as white smoke.

Also Read:  Timing Chain vs Timing Belt: Understanding the Key Differences

The friction between the engine’s moving components increases as the oil level drops. Because of these things, the engine’s heat will rise and eventually reach the air conditioning system.

Deteriorated parts

A great deal of heat is generated or transferred to the air conditioning system by worn-out engine parts or other cooling system components, such as the fan motor. White smoke could be expelled from the air conditioner vent due to the heated air, as mentioned earlier.

Over time, the cooling system’s components will wear out and eventually fail, leading to an increase in engine temperature.

When the air conditioner stops working, more hot air is pushed into it to cool it, which eventually leads to condensation. Excessive condensation will cause white smoke or fog to billow out of the air conditioner’s vents.

Too much use of the heater

The heater’s core is susceptible to damage and potential leakage if used excessively. Under the dashboard is where you’ll find the heater core and a little radiator is there to catch the hot coolants.

White smoke is produced when coolant flows into the engine due to a damaged heater core, where it is burnt. The issue of coolant smoke emanating from vents is caused by it. White smoke is produced, recirculated within the air conditioner, and then released through the vent as this process progresses.

Oil leak

Oil can leak out of the oil reserve and into the engine if the cover isn’t tight or if there’s a leak in the reserve. Because of the high temperature of the engine, the oil will be burned in such spots, resulting in a white fume that could reach the air conditioning vent.

Also Read:  Power on the Go: Understanding Alternator and How It Works

People have a hard time enjoying the drive due to the awful, choking odour of the white vapours produced by oil leaks.

High humidity

When the relative humidity near the air conditioner is lower than the rest of the car, fog-like smoke will be expelled out the vent. Fog is distinct from smoke; unlike smoke, the odour of smoke emanating from vehicle vents is not of burning or oil. A pleasantly chilly weather has arrived.

Blocked pipe for draining

To remove the collected condensation, older cars typically contain a drain hole. Water will eventually pool to a particular level if the drain hole becomes clogged. White smoke will be expelled from the vents once it evaporates in the air conditioner.


If smoke is billowing from your car’s air conditioner, you should take note. The smoke that comes out of the air conditioner vent can be a rainbow of hues and textures. You should get the car checked out the moment you see any strange smoke coming from the air conditioner vent. If you don’t take immediate action, you can end up spending a fortune fixing your engine, which could indicate a more serious problem.

Leave a Comment