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How To Correctly Diagnose a Smoking Turbocharger

How To Correctly Diagnose a Smoking Turbocharger

Turbos are generally pretty sturdy, but like the other components in your engine, they wear down with time and use and can eventually break—or even fail.

One common sign of a blown turbo is smoke coming from under the hood or from the exhaust. But excessive smoke can also be caused by a myriad of other issues. How can you tell whether it's caused by your turbo or something else?

Pinpointing the exact cause of a smoking engine or exhaust isn't easy, but it's far from impossible. If you have a hunch that your turbo is causing the smoke, it's important to investigate further so you can snuff out the problem.

Here's how to correctly diagnose a smoking turbocharger based off the color of the smoke and other common warning signs of turbo failure.

What Causes a Turbo To Smoke?

Turbos usually don't create smoke that originates from under the hood, but it occasionally happens. More frequently, you'll observe thick, billowy smoke coming out of the tailpipe. Regardless of where the smoke is coming from, it's potentially a sign of a blown turbo.

Suspect the smoke coming from under your hood or from your exhaust is due to a blown turbo? The easiest way to confirm your suspicions is to examine the color of the smoke and, of course, crack open the hood and inspect the turbo itself.

Understanding Exhaust Smoke Colors

Exhaust smoke comes in a variety of colors. The most common exhaust colors include black, blue, clear, gray, and white. Each color indicates a different kind of problem within the engine. Here's a handy guide to exhaust smoke colors to help you determine whether the problem is your turbo or something else.


Black smoke appears when the vehicle is burning too much fuel as a result of running fuel rich. Common causes include a blocked air filter, an obstructed air intake duct to the turbo compressor, and faulty fuel injectors. Black smoke usually goes hand-in-hand with serious performance issues. The sooner you remedy the issue, the sooner you can get back to cruising down the highway.


Blue or gray exhaust smoke is an indication of an oil leak. Common causes of blue smoke include damaged piston rings, leaking valve seals, and worn cylinder walls. Blue and gray smoke can also be a sign of a damaged turbo. A sludged or coked bearing housing, a restricted oil drain line, or a broken oil seal is normally the guilty culprit, but other kinds of damage to the turbo can also result in blue smoke.


Thin clear or white smoke is completely normal. This kind of smoke consists mainly of water vapor. It appears because of the condensation that naturally accumulates in the exhaust system over time. So, if you notice thin clear or white smoke when you start your vehicle, don't worry—chances are, nothing's wrong.


Thick white exhaust smoke is usually caused by coolant issues. The most common cause of white smoke is a leaking head gasket. When the head gasket leaks, coolant is heated in the combustion chamber and then blown out of the exhaust when you start your vehicle.

A coolant leak is especially dangerous in the summertime because it makes the engine more prone to overheating. White smoke rarely ever indicates a problem with your turbo, but it's something that you should have checked out anyway.

Symptoms of a Failing Turbo (And What They Mean)

A lot like the check engine light (CEL), exhaust smoke is more of a general warning. It informs you that something is wrong but doesn't offer much insight into what the problem actually is. It's hard to correctly diagnose a smoking turbocharger when all you have to base your guess off of is the color of the smoke.

Blue and gray smoke (and occasionally black smoke) can both point to problems with your turbo, but they can also mean a lot of other things. So, how do you know whether the smoke is caused by your turbo? By keeping an eye out for other telltale signs of turbo failure, of course!

Here are some common symptoms of turbocharger failure to watch out for. If your car produces excess smoke and also experiences one or more of these other problems, it's a good indication that your turbo needs repairs.


Speaking of the CEL, an activated one can point to turbo issues. Of course, a lit CEL can mean a lot of other things, too, so don't immediately jump to the conclusion that it's your turbo that's causing it to light up.

Poor Performance

Turbos are supposed to boost performance, not hamper it. If your car is performing more sluggishly than usual, it could be because of a blown turbo. You might notice slow acceleration or a lack of boost at high RPMs.

Increased Gas Consumption

Turbos are also supposed to improve fuel economy. If you feel like you're spending more time and money at the gas station than you did before, your turbo could have an oil leak.

Odd Noises

Do you hear a loud, siren-like noise coming from the engine? This sound points specifically to a faulty turbo. The louder the sound, the worse the problem usually is.

How To Fix a Smoking Turbo

Depending on the complexity of the problem, the amount of knowledge you have on turbos, and how handy you are, you might be able to fix your turbo yourself. With the right tools, components, and a bit of elbow grease, you can get your turbo up and running again in no time.

But in most cases, it's recommended you drive your vehicle down to a local auto shop and have a certified mechanic inspect, troubleshoot, and repair your turbo.

Need turbo replacement parts to fix your blown turbo? Turbo Turbos has everything you need to get your turbo up and running again. Looking for a new turbo? We have that too—come and check out our selection of new, used, and rebuilt turbos sale. For all your turbo needs, shop with Turbo Turbos!

How To Correctly Diagnose a Smoking Turbocharger

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