Smoke from tailpipe exhaust? Auto Repair Shop Precision Motor Coach in South Windsor CT Explains

Do you have smoke coming from your car’s exhaust?

Typically, if you can see smoke coming from your car’s tailpipe, it’s an indication that there are problems with your engine. It doesn’t necessarily mean you need to replace your engine, but to determine the cause, you need to consider the color of the smoke.

There are three common colors of smoke that come from car tailpipes. They are white smoke, white smoke, blue smoke and black smoke.

White Smoke from your car’s tailpipe:

Usually this is caused by water or antifreeze. In reality, the white smoke is actually steam. The steam or white smoke is created because your car’s engine is burning coolant.

The most common problem stems from leaks in the cylinder head gaskets – often called head gaskets. Head gaskets seal the cylinder head where it attaches to the engine body. The gaskets prevent coolant or antifreeze from entering the combustion chamber where fuel and air mixture is compressed and burnt.

Any amount of antifreeze that enters the cylinder will produce the white smoke or steam that you see coming from the tailpipe area.

What should you check if you see white smoke coming from the tailpipe?

The first check would be to see if there is the correct amount of coolant or antifreeze inside the radiator overflow. Check carefully to see if the antifreeze is contaminated with engine oil .

Next, check the engine dipstick for any signs of the oil being contaminated with antifreeze. Additionally, check the underside of oil fill cap. When oil is contaminated with antifreeze, the color of the oil will be similar to a chocolate milkshake.

If your car’s engine oil is contaminated, do not start the engine. There is most likely serious internal engine damage – and operating the engine could make it worse.

How does antifreeze or coolant get into the engine oil? This usually occurs as a result of the engine being overheated. Excess heat causes the head gasket to fail. That allows the coolant or antifreeze to enter the combustion chamber (cylinder).

Blue smoke coming from your car’s tailpipe

Blue smoke is an indication that engine oil is being burnt along with the fuel and air mixture (in the engine’s cylinders) This is more likely to occur in older vehicles with higher mileage.

How did the engine oil get inside the cylinder in the first place? The vehicle engine has many seals and gaskets that are designed to keep the oil from entering the cylinders.

The blue smoke coming from your car’s tailpipe is an indication that one or more of those seals or gaskets has failed.

Excess amounts of oil being burnt in the cylinders will cause the spark plugs to foul. When spark plugs foul, your engine starts to misfire. (Often called an engine miss)

Black smoke coming from your car’s tailpipe:

Black smoke is an indication of excess fuel entering the cylinder. Because the air/fuel mixture is critical to efficient combustion, the excess fuel cannot be burnt.

This condition is often referred to as ‘running rich’. This condition can cause poor fuel economy (bad gas mileage), poor engine performance and produce an odor of fuel.

How did the fuel get into the cylinder in the first place? On older vehicles using a carburetor, the carburetor is out of adjustment. Other causes for excess fuel or ‘running rich’ could be a faulty fuel pump, a leaky fuel injector, or a faulty engine computer or computer sensor.

If you have black smoke from your car’s tailpipe, check the engine oil and make sure excess fuel has not contaminated the oil. In the case of fuel contamination, there will be a distinct odor of raw fuel in the engine oil.

In either of the cases listed above, the smoke from your tailpipe should not be ignored. Contact us or book your next service appointment to determine the reason why smoke is coming from your tailpipe.