Why Is Smoke Coming Out Of AC Vent In Car?

Have you ever notices smoke coming out of ac vent in the car? It creates a panic situation, and thus, you check all the connections of wires or search for a short circuit. But you find nothing wrong, and also everything is in place as it should lie. Then, what’s the issue? Where is all this smoke in the vehicle coming from? And so on, questions arrive in your mind. The answer to all the multiple questions lies within this article. As we’ll move further, we are going to discuss every point regarding the matter. Also, we will learn and gain knowledge on how to deal with or tackle the situation whenever stuck in one such kind.

For a brief intro, you often observe smoke from the air vents by the cold and dry air coming in contact with the warm air. The temperature near the unit reaches below the dew point, water vapour forms in the air, which soon changes into water droplets, thus causing fog or smoke.

So, let’s begin with the discussion over the topic covering common reasons and their fixation.

Why Is Smoke Coming Out Of AC Vent In Car?

The first step regarding any problem is to find its cause, and after seeing the reason, you can consider the methods to cure or correct the defective function within the system. However, smoke from the ac vent is not an issue that may be neglected. Therefore it is better to achieve specific knowledge regarding the same.

Here, we will briefly discuss the specific points over fixation of the AC compressor, which results in releasing smoke through its vent.

1. Blown Heater Core

A heater core is generally a radiator where the hot engine coolant runs through the heat up the interior of the car. Whenever you observe a sweet coolant smell from the vent, it means you have a low coolant level, and the smoke seen from the ac vent is because of the blown heater core.

A fan is blowing across the heater core functions to allow the air inside the car to heat. Thus, it would generate smoke if the heater core leaks or malfunctions whenever the air conditioner switched on in the car.

Hence, to avoid all these unexpected and uneven situations, it is better to keep track of the coolant level in your vehicle. As in some cars, there is no odour present in the coolant, making the identification of leaks difficult. So, it’s good to have a timely check over the heater core and the level of coolant in the car.

However, you must always prepare and adapt yourself for these regular maintenance services of the vehicles to avoid any mishap or future problems.

2. Faulty Compressor Clutch

One of the reasons behind the smoke from the vent is the damaged compressor clutch. The fault in the compressor clutch is because of an overcharged system in the vehicle.

There are chances where the compressor does not short but faces some of the other minor faults or defects. These defects may include the compressor clutch being fast, the compressor belt may slip very severely, and the solenoid responsible for engaging and disengaging the grip may have deteriorated.

In such cases, you can replace both clutches as well as compressors. The replacement of the compressor is generally preferred as it is an easier task than the clutch replacement. The average time required for the replacement is thirty to forty minutes. However, professional workers perform even less than the time stated above.

Soon, after you are done with the compressor, please remember to discharge and charge the system. It will ensure the proper working of the system along with the best outcomes.

3. Depleted Oil

The emission of smoke from the ac vent also caused by the depleted oil level in the car. It observed so because the burning requires oil. It is preferred not to switch on the ac whenever you are running the car in such situations. Otherwise, it would ultimately damage your compressor.

And replacement of compressor requires hundreds of dollars which is quite a large amount. So, it is better to prevent these situations than pay a lot because of laziness or ignorance.

So, the causes mentioned earlier generally deal upon or work on a single phenomenon, i.e., when the cold air hits the warm air, it results in the generation of smoke or fog. The condition worse when the interior temperature of the car is much higher than the outside environment. It also gets worse when humidity increases inside the car.

How Much Does It Cost To Fix Smoke From AC Vents?

Depending upon the reasons, each cause requires a heavy replacement. Although, in some cases, we can correct the issues by owning, there also need specific guidance to perform the task properly.

Here, we can see that the least cost of repair lies when we change the oil, but the maximum expense expected during the ac compressor replacement. Thus, we can estimate that the average price of fixation may reside somewhere between $300 to $1000. This includes the labour charges also.

However, the prices and ranges may vary from place to place and vehicle to vehicle. Also, the professionals require additional charges due to their excellent service.


So, from the points mentioned above, it is clear that the smoke from the ac vents is not a common failure observed in vehicles. There may reside a variety of reasons behind this. But it based on a single principle that is followed all over the system. Also, it’s recommended not to drive the vehicle until the problem is completely solved.

We hope all the readers are pleased and satisfied with the matter stated in the article. So, whenever you are stuck with smoke coming out of ac vent in the car, don’t panic and act according to the condition stated.

If your doubts regarding the topic persist, comment below in the comment section. And we will surely answer all the questions as quickly as possible.