What Does It Mean If I See Black Soot Coming Out Of Exhaust?

Gases coming out of the exhaust can be really unnoticeable since it is the work of exhaust to quietly pump outspent gasses from the combustion process from the back of the vehicle. But sometimes you do notice that it is coming out in a huge amount with different colors such as blue, white, or black smoke. If you see these you have to understand there is some problem in your car, due to which you see black soot coming out of exhaust.

This different kind of exhaust smoke can be coming out in any conditions which can be the car is stationary or accelerating which can be a sign of some serious issue in your car. This might cost you spending a lot of money on some expensive repair bills.

What Does Smoke Coming Out Of Exhaust Symbolises?

Exhaust-releasing smoke can be just fine until you see something unusual coming out of your exhaust. The different kinds of smoke tell about the different conditions your car is going through. Also, it varies according to the model of your car, how well maintained you have managed your car, and what is the state of the car while the smoke is releasing( is it well accelerated or at a stationary position).

It also depends on whether your car has a petrol engine or a diesel engine or if you drive a hybrid, you too could see your exhaust putting out something that you might not be prepared for. Different kinds of smoke show you different kinds of signs let us discuss what does a smoke color tells you about the condition of your car.

1. White Coloured Exhaust

When a cold engine is turned on it begins to heat up and a byproduct of this heating is water vapor, which creates condensation in the exhaust system that turns into steam as temperature rise within the engine. So the irony is the most common form of smoke is not actually smoke at all. Once your car is heated up enough the steam evaporates, but the problems arise when you are using the car for long journeys due to which the exhaust system doesn’t get completely warmed up till the top of your exhaust.

So if the condensation formed by the system doesn’t get exhausted it can remain stuck there and corrode the steel of your exhaust, causing it to damage and develop rust. This rust can cause your exhaust to leak and blow from the system where the exhaust gas leak out.

If the white smoke coming from the exhaust is thicker and doesn’t stop, it is still steam, but also an indicator of a more severe issue that will be caused by your car’s coolant leaking into the engine, which is caused by a failed head gasket.

2. Blue Smoke From Exhaust

If you are smelling a burning smell and seeing blue smoke coming out of the car’s exhaust, it certainly means that there is some oil entering into the system. Engine oil is designed to lubricate moving parts, and it doesn’t enter the fuel system if a car is running properly. If you have recently changed the oil it is very well certain that you have put too much oil and the excess oil is burning out.

When you see your smoke is blue in color, it means that the piston rings are worn out which allows the oil to enter the fuel system around the cylinder or valves.

3. Grey Smoke And Its Causes

Similar to blue smoke the grey smoke is a sign that your engine is using an excess amount of oil, or turbo is damaged. But there are more layers to the grey smoke. Your PCV valve the is the basic form of emissions control may become damaged and started to draw unburnt fuel back into the lower part of the engine to the top. This helps to reduce vehicle emissions, but after a time period they can wear out.

If you drive a car with an automated gearbox then the reason for grey smoke can vary. The reason might be the transmission fluid is being sucked into the engine through a leak in the system.

4. Black Soot Coming Out Of Exhaust

Black smoke is caused by different factors, it particularly depends upon the type of car you are using it can be either a petrol car or a diesel car. In a petrol car, black smoke is a sign of a lot of fuel burning.

But in diesel cars, it could be soot build-up from unburnt diesel. The diesel particulate filter is designed to trap soot from unburnt diesel before it pumps out of your car’s exhaust. But if you only drive your diesel car at lower speed the soot deposits may build up over some time which could result in a warning light flashing on your dashboard.

How Do You Fix Black Soot Coming Out Of Exhaust?

1. In Case Of A Petrol Car

Here are the measures you can take if black soot is coming out of exhaust from your petrol car.

  1. First check or replace the air filter in your car.
  2. If it is not the fault of an air filter check whether the fuel injectors are clogged.
  3. Also, check if the fuel pressure regulator is clean or not.

If you are not comfortable in doing that you can ask any mechanic to do that for you.

2. In Case Of A Diesel Car

Here are the measures you can take if black soot is coming out of the exhaust from your diesel car.

  1. Drive your car faster so that fuel/air mixture flows through the car faster. This will dislodge the soot which will be appearing as a black ball of smoke left behind by the car.
  2. If the warning light still flashes up continuously, then a diesel car might not be right for the kind of driving you to do, and it might be worthwhile changing to a petrol or hybrid model instead.

Still, you can check out an expert and ask him to give you suggestions overall.


Now, you know different kinds of smoke your engine can release and on factor it depends. You also know what does those different kinds of smoke symbolizes about your car’s condition. How to fix black soot coming out of car is also discussed above.

If you still have any further inquiry then you must comment your questions down below.

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