It is such a bad driving day if you find the white smoke from hood when AC is on. You see that driving does not always bring thrilling moments. Sometimes, it could drive you insane with troubles, for sure.
That story tells about our problem, and maybe it’s yours, too. One day, the weather is super-hot outside.
But you detect that the car starts smoking when AC is on, or the AC doesn’t work when it’s hot outside. So, what’s wrong with the vehicle? Can you fix it yourself or need to meet an experienced mechanic?
For better protection, it’s time to find the answer and save your cars. First, let’s discuss the causes. So, why is there smoke coming out of my AC?
Why’s There White Smoke From Hood When AC Is On?
One of the most common causes of smoke coming out of AC vent in car is when the coolant gets into the combustion chamber (maybe through a blown gasket).
Other reasons lie in the compressor or AC faulty compressor clutch. Any wear and tear, fluid, or leak of these parts can result in friction and unexpected burn.
A well-functional air conditioning helps enhance your experience.
If there are problems with this system, one of the most typical signs will be the mist coming out of car AC. Sometimes, it even comes with a strong burning smell.
In this article, we focus on the reasons for smoke coming from AC vent in car. In particular, both engine overheating and not-overheating conditions stay with our discussion for a deeper explanation.
A Detailed Explanation
Inside the car, a compressor clutch transfers power from the engine through the pulley to the AC compressor. This power flow makes the AC system operate in a cool temperature condition.
The AC system often requires lots of power while running. If it keeps working all the time while the fuel tends to run on empty, the engine will wear out.
As a consequence, your vehicle’s AC almost turns bad. For protection, the compressor clutch will turn on the AC system only when the driver needs it.
You can consider the air conditioning compressor as your vehicle’s heart in another way of explanation. At the same time, the compressor clutch plays as a pacemaker maintaining the heartbeat.
Thus, any leak in the compressor or broken piece in the clutch can lead to AC blowing smoke in car.
Unexpected Issues
Is it a severe issue for smoke coming out of AC vent? Despite being a sign related to the vehicle problem, it is unnecessarily unusual trouble.
If you do not smell anything strange, there is no need to worry too much. It could be steam or vapor. When the airflow meets the accumulated water at the heater box’s bottom, the case can occur.
The condensation could leave a restriction on the position of the drain hole that needed to be cleaned.
Most drivers can fix that problem by cleaning and drying the system with a running fan. On the other hand, you can also have it cleaned by a service that costs around $45.
We still suggest doing it yourself since the process is quite easy.
If the steam or visible vapor has a sweet smell, it is time for you to worry a bit. The fault is because the engine coolant leaks at the heater core.
You will find a refrigerant spray from the air conditioning vents as a clear sign. The bigger the leak, the more severe the hot engine damage will be.
Why Is There Smoke Under The Hood But Not Overheating?
Smoke coming from AC vent without overheating means that no fire starts the problem. There is no need to call the fireman, too.
Although smoke often goes with overheating the car (or the car won’t even start), we find several different situations. They include a normal condensation, coolant leak, bad oil filler cap, engine oil leak, etc.
- Normal condensation: When you drive the vehicle, water under the engine hood will burn off. Smoke, in this case, is odorless with white color.
- Coolant leak: The fluid can easily drop onto the engine with an overflow coolant tank. Then, it evaporates into strange white smoke that smells sweet.
- Bad oil filler cap: Fuel can escape due to a broken oil filler cap, for example. As a consequence, the fuel gets burnt by the car engine. Besides, a clogged PVC tube or a worn piston ring could result in this problem.
- Oil leak: Due to several possible causes, the oil leaks and burns within the car engine. Sometimes, a bad valve seal or head gasket failure is the main reason. The white exhaust smoke often has foul smells like burnt asphalt.
- Others: If the cool smoke is not overheating, it could result from the burnt copper wires for replacement. The white exhaust smoke will bear a typical chemical odor.
Whatever the problems are, it would be better for you to have the car checked and fixed by a mechanic.
There are many mechanical failures that you cannot detect yourself. Timely protection can help avoid lots of possible damages in the future.
How To Fix White Smoke From Hood When AC Is On?
The first thing to do with the fog coming out of AC vent in car is to pull over your car hood. One note is that you should do it only when the situation is safe.
Next, let’s get started to detect the problem. If you are not confident enough, calling for roadside help will be the best alternative.
- If the vehicle is overheating, the car dashboard with warning lights will let you know. We suggest not popping the hood and waiting till the automobile engine cools down.
- When the vehicle is not overheating, the problems could be normal condensation, electric problems, oil leaks, etc.
In case the fluids drop and start forming on the road, you should call a mechanic. Then, he could replace the air conditioner compressor clutch/broken seal, fix the oil leak, or recharge the AC system.
Regardless of causes or ways of fixing, frequent car maintenance is always the best solution. For years, it can protect your vehicle from severe damage.
Conclusion
It is unnecessarily a big common issue for white smoke from hood when AC is on. But sometimes, it could bother you a lot.
In general, smoke coming through AC vents is often the consequence of several faulty parts like the AC compressor clutch.
For solutions, we mention some common ways above. However, you can also ask a professional mechanic for help.
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