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Smoke coming out of car AC vents is common, and in most cases it’s condensation, which most people know is harmless. In this article, I have explained what condensation is and have debunked some myths regarding AC vent smoke, too.
Understanding the Causes and Types of Smoke Coming From Car Vents
In the majority of cases, smoke coming out of car vents is a result of condensation. The car’s AC pulls warm air and then cools it; during this process, the heater core can get condensation, which eventually turns into vapor and comes out of AC vents looking like white smoke; in simple words, it’s just fog, which is harmless.
In some cases, a burning smell can come out of air vents, too, which can be a result of a significant component failure, but the colored smoke, like black, blue, and gray, comes from the exhaust, not from the vents.
There is a lot of false content on the internet regarding the type of smoke and its color that comes out of AC vents. The white, gray, blue, and black smoke often comes from the exhaust pipe when the car has some issues, not from the AC vents like some websites have mentioned.
Let’s talk about the types of smoke and their reasons.
1. White Smoke
White smoke is mostly caused by a coolant leak or a blown head gasket, or it could be because of condensation, as described before.
2. Blue Smoke
Blue smoke coming out of AC vents is a clear sign of worn-out piston rings, valve seal problems, or engine oil leaks.
3. Black Smoke
Clogged air filters and issues with the fuel system are mostly the reasons behind black smoke from car vents.
Note: These are the most common reasons behind the smoke; there can definitely be more reasons.
What to Do if Smoke Is Coming Out of Car’s Air Vents?
Before we dive into the troubleshooting steps, let’s talk about the safety measures first. Basically, you do not have to do anything since it’s just fog, but if a severe amount of unusual smoke is coming along with a burning smell. Pull over to a safe place, turn off the engine, and get out of the vehicle.
After that, you can try to figure out the actual situation by following the advice mentioned in this article. If you are a complete layman, you should call a mechanic to get it fixed.
1) Check for Dashboard Warning Lights
Warning lights illuminate the dashboard in case of technical faults; they are the easiest ways to identify a technical fault. Along with the warning light, make sure you check for changes in the temperature gauge, too.
2) Look For Visible Faults under the hood
Open the hood and look for visible faults such as coolant/oil leaks and see if there is anything unusual. Also, check both coolant and engine oil levels. Low coolant/engine oil level is a big red flag and causes issues like smoke along with a burning smell.
3) Unclog the Drain Hole
Some old car models have a drain hole to remove excess moisture; if the drain hole is clogged, water will not drain and finally result in condensation.
Unclogging the drain hole should fix the issue. Make sure
you locate the drain pipe, which is located near the evaporator heater box; once you find it, unclog it by attaching a hose to it and then run water to remove debris using water pressure; make sure you detach the drain pipe first.
What Else Can You Do?
I have not explained some solutions in detail since most of them are not DIY solutions, and you have to take the car to a mechanic, but if you are skilled enough, below I have mentioned more recommendations to fix the issue.
- Check for wiring fire
- Clean the air filters
- Inspect the AC duct actuator
- Inspect the car’s clutch plates
- Inspect fuel injector components
- Replace the heater core or check for leaks
Is It Safe to Drive With Smoke Coming from Car Vents?
If the smoke is extensive and has a burning smell, too; in that case, you should not drive or even turn the ignition on. If it’s just fog due to condensation, you can drive the car.
How do we Differentiate between Harmless Condensation and Major Fault?
Condensation results in odorless fog, while other smoke issues are often accompanied by a burning smell, which could be because of wiring or other faults. Additionally, a major component fault will result in warning lights popping up on the dashboard or a change in the temperature gauge.
As mentioned before, smoke coming out of car AC vents is common since it’s condensation, but if it’s not condensation, then it’s definitely not common, and the vehicle should not be driven.