Color plays an important role in both driving and auto maintenance. When it comes to driving you know green means go, yellow means slow or caution, and red means stop. In one of our more recent blogs, we mentioned that your dashboard lights are usually color coded, much like traffic lights, so that you can determine their level of importance. So, what does the color of your vehicle’s exhaust mean?

Changing exhaust colors could indicate a few different things. It could be nothing, or it could be a sign that there is something wrong with your vehicle that you need to have inspected. Here is a list of four different exhaust colors and what they could mean for your vehicle. (Please note that the following information is in regard to gasoline engines and is not meant for diesel engines.)

Light or Thin White Exhaust Smoke

It is considered normal when the exhaust coming from your vehicle is light or thin white. This type of smoke is usually just water vapor. You will notice it when you first start your vehicle, especially on cold days. The reason for this form of exhaust is that condensation collects naturally in the exhaust system. This exhaust is common in all gasoline engine vehicles.

Blue/Gray Exhaust Smoke

It is not considered normal for there to be blue/gray exhaust smoke coming from your vehicle. This type of exhaust usually indicates that you have an oil leak and that the engine is burning oil. There are multiple issues that can cause an oil leak, such as worn cylinder walls, leaking valve seals, or damaged piston rings. When there is blue smoke at acceleration, the problem is most likely with the piston rings. If it’s during deceleration, the blue smoke likely indicates that the cylinder head valve guides are damaged. In either case, your vehicle needs to be brought in to a professional. Take note of when you see the blue smoke and share the information with our technician when you bring your vehicle in for service to help them with your vehicle’s diagnosis.

Black Exhaust Smoke

It is not considered normal for your vehicle to be emitting black exhaust smoke. When it is, it typically indicates that your vehicle is burning too much fuel. Several things could cause this to happen, like a blocked manifold, a clogged air filter, a malfunctioning fuel injection system, amongst other possible problems. If your exhaust smoke is black, bring your vehicle in to Meridian Automotive and have one of our expert auto mechanics see why your vehicle is burning more fuel than normal.

Continual, Thick White/Gray Exhaust Smoke

A continual stream of thick white/gray colored exhaust smoke coming from your vehicle is not normal, and likely means you have a leaking head gasket. Automotive writer Paul Brand explains that in the case of persistent, thick white/gray exhaust smoke “the coolant would end up being heated in the combustion chambers and blown out the exhaust as the engine starts.” In the summer, this could quickly lead to an overheated engine. Another possibility for this kind of exhaust to come from your vehicle would be a cracked cylinder head or block, both of which are serious problems that need correcting right away. Putting off repair when your vehicle is emitting continual, thick white/gray exhaust smoke could result in very expensive damage.

If you have noticed a color change in the exhaust of your vehicle, don’t hesitate to visit the automotive professionals at Meridian Automotive. We are here to help you with all your auto repair needs. We provide complete automotive repair in Meridian, Idaho, for most cars, light trucks, and SUV’s. For over 20 years we’ve been Meridian’s auto repair experts. Don’t just trust anyone, trust the experts at Meridian Automotive. Call us today (208) 297-5573 or schedule an appointment online.

Related Post


Ready to experience the
meridian automotive difference?

We can fix what you need!