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Cheat Sheet: What Does the Color of My Exhaust Smoke Mean? (Black, White or Blue)

Exhaust smoke is a necessary evil of internal combustion engine-driven vehicles, and if the smoke coming out of your exhaust pipe is the right color and not especially noticeable, everything is fine. But what happens when colors of smoke are coming out of your exhaust pipe that you don’t expect. If you see white, heavy gray or blue or black smoke coming from your exhaust pipe, you are probably rightly assuming that something is wrong. Read on to learn the answer to the question: What does the color of my exhaust smoke mean, and what should I do about it?

White Exhaust Smoke

White smoke is probably the trickiest kind of smoke color to deal with because, depending upon what kind of white smoke you are getting and how it behaves, it could be nothing at all to worry about or it could be a serious problem. Here are the different kinds of white smoke that your exhaust may be generating and what it may mean.

If you have light white smoke coming out of your exhaust, you’re probably okay. This may just be due to condensed water vapor and is very common, especially when starting your car for the first time on a cold day. It is generally nothing to be concerned about.

However, if you are getting thick white or gray exhaust smoke coming out consistently that dissipates shortly after it comes out of the tailpipe, it often means your head gasket is blown or leaking. That’s not good news. This color is often a product of coolant leaking into the combustion chamber. If the smoke doesn’t dissipate right away, it could be burning oil, which you want to approach the same way you would approach blue smoke coming out of the exhaust pipe.

Very heavy white or gray smoke may also be an indicator of a much more serious problem like a cracked engine block or broken cylinder head. These are problems you will want to address immediately while your car is still functioning.

We talk to customers every day about exhaust issues that hint at a head gasket problem – either a leaking head gasket, or a more serious blown head gasket. We have forged a lot of our reputation in fixing blown head gaskets for a fraction of the price of a hard (physical) repair. To check out what we have in our product lineup for head gasket problems, see here. Of all of our products, Head Seal Blown Head Gasket Repair (HG-1) is the strongest and most professional-grade, and is used by mechanics when the situation warrants.

Blue Exhaust Smoke

You will no doubt be quite alarmed if you detect blue smoke or bluish gray smoke emanating from your exhaust pipe. You are right to be concerned. If you are noticing blue smoke from the exhaust, it means your engine is burning oil due to an oil leak. This symptom could be the result of a leaking valve seal or a problem with a piston ring.

What is happening is that the engine seals are not effectively sealing the oil from getting into the cylinders. That escaped oil can then mix with the fuel and burn as the fuel burns. This effect immediately produces the blue exhaust smoke you are seeing.

If the blue smoke occurs when you accelerate, it is usually a piston ring issue. Sludge and carbon can get in and around your piston rings and stick them, so that they cannot work properly. On the other hand, if blue smoke happens during deceleration, you are usually looking at a cylinder head valve guide issue.

Other signs that your oil is leaking into your fuel and burning are misfiring spark plugs and rough vibrations while idling, but the blue smoke is an unmistakable, tell-tale sign of this issue.

Black Exhaust Smoke

Black exhaust smoke is usually an indicator that your car is burning fuel excessively. Causes can include a problem with your fuel injectors, a clogged air filter or a blocked intake manifold. In addition to being unsightly, this condition could hurt your car’s performance.

How to Repair and Prevent Blue and Black Smoke Coming From Your Exhaust

If you are getting very heavy white smoke from your exhaust, check out our head gasket solution lineup, as mentioned earlier.

If you are dealing with blue or black smoke, however, the mechanic doesn’t have to be your first stop.

Bar’s Leaks is famous for developing products that are known as “mechanics in a bottle” because in some cases they can allow you to avoid a costly trip to the mechanic or dealership. In the case of blue and black exhaust smoke, the solution may be Bar’s Leaks Oil Seal Engine Oil Burning & Leak Repair. This pro-grade product is designed to stop the leaking oil or fuel that can lead to burning and colored smoke by renewing worn-out valve seals and cylinder head valve guides and repairing leaking main seals and gaskets. It’s the most advanced oil product we’ve ever made.

One of the most common causes of oil leaks, which can lead to blue smoke, is the hardening and shrinking of engine seals. This is especially true of older cars, as the plasticizers in these seals degenerate over time. One of the main functions of the oil seal engine oil burning and leak repair product is to revitalize these seals, renewing and refreshing them so they become effective at keeping oil in once more.

A major benefit of this product is its versatility. It works for all engines and all oil types. Whether you use standard oil, fully synthetic oil or a synthetic blend, this product can mix with your oil safely. It stops virtually every oil leak you are likely to encounter in your vehicle, from main seal leaks to valve seals, cam seals, timing cover seals and crankshaft seals. It can also stop leaks in your valve cover, oil pan and more.

In addition to its seal-restoring additive, this product contains a seal polymer additive that reinforces the seal with a polymeric film, along with synthetic polymers to fill in minor scratches and wear marks and a detergent and cleaning package to clean gunk from your piston rings to free them so they can work normally.

Choosing off-brand engine additive products that are not Bar’s Leaks will not provide the same results. To find the nearest distributor of Bar’s Leaks products to you, use this locator guide. For more information on this product or other stop-leak products by Bar’s Leaks, hit us up on our Bar’s Leaks contact form. We’re always happy to help.

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