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Reading Smoke — What Your Exhaust’s Smoke Means

Reading Smoke — What Your Exhaust's Smoke Means
October 10, 2016

Why is my diesel engine smoking? Why does my diesel smoke? If these questions are currently on your mind, you’re in the right place. Seeing smoke coming from a diesel engine can be a common sight for many owners. However, this smoke could be an indicator of an issue with your diesel engine that deserves your attention.

Check out our guide below to learn more about common types of smoke, their causes and how you can address the issue to eliminate the smoke. 

Grey or Blue Diesel Smoke

If you’re noticing grey or bluish smoke coming from your engine, there could be a few possible causes. Let’s go over some of the most common causes of grey or blue diesel smoke and how you can fix the issue to keep it from coming back. 

Causes of Grey or Blue Diesel Smoke

Blueish white smoke coming from the exhaust usually means that you need to take a look at the oil. Noticing a burnt-oil smell or seeing blue/gray smoke leave your exhaust on startup or heavy acceleration are common signs that you are burning oil. Other common causes of blue or grey exhaust smoke include poor seals on piston rings, valve seals, PCV valves, injector o-rings, or turbo seals. 

How Do You Stop Grey or Blue Smoke From a Diesel Engine? 

There are a few low-cost solutions you can try to find the cause of the blue smoke and stop it from coming back. If you suspect you might be burning oil, Stiction Eliminator is an excellent place to start. It’s an efficient oil treatment for both gasoline and diesel engines. It works by removing the built-up sludge and varnish created by burnt oil and lubricating your engine. The stiction eliminator can also clean other engine components such as the oil pump, HEUI injectors, pistons and more. This high-quality oil treatment can help reduce friction in the engine, lower engine operating temperatures and make the engine run efficiently and smoothly. Stiction Eliminator belongs first on the list due to its money-back guarantee and ease of installation. 

Another option you can try is to run a compression test. Many auto parts stores offer compression test units for rent, with your money back when you return the tool. It’s a straightforward test for the backyard mechanic and can help show the condition of your engine, enabling you to identify the cause of the smoke. You could also try replacing your PCV valves. These valves can sometimes go bad and suck oil into the intake, depending on the vehicle. 

Be sure to consult your mechanic if you’re unsure of your next step and need help identifying the causes of the smoke. 

White Diesel Smoke

White Diesel Smoke

White diesel smoke can sometimes be a sign that there is a larger issue with your engine. Here are some of the common causes of white smoke and how you can eliminate it:

Causes of White Smoke From Diesel Exhaust

White smoke may be a form of condensation if it is thin and quickly fades away. However, thicker, longer-lasting white smoke could be an indicator that you need to address a larger problem. One common cause is that your engine could have an issue with burning the coolant. This could happen because the head gasket has blown, the cylinder head is damaged or the engine block could be cracked.

White smoke can also be a sign of fuel passing through the engine and reaching the exhaust without having been burned. A few reasons for this issue could be an engine that isn’t hot enough to burn the fuel, low compression in the cylinder, issues with the fuel injectors, a clogged air filter, burnt-out glow-plugs, or the use of low-quality fuel. 

How Do You Stop White Smoke From a Diesel Engine? 

Diesel Extreme is the go-to solution for this color smoke since it attacks many of these issues. It works by improving the fuel’s cetane. This improvement allows fuel to ignite properly at a more desirable temperature once it enters the combustion chamber. Diesel Extreme is one of the most powerful detergents on the market. It can also remove water, bacteria and break down sludge, completely cleaning your entire fuel system, from the tank to the injectors, increasing your diesel’s fuel economy, horsepower and more. 

We also offer Gasoline Extreme for gasoline engines. It can help attack many of the common causes of white smoke by cleaning fuel injectors, pistons, pumps, valves and more, while also restoring fuel performance.

Another fix for white exhaust smoke might include adding an automatic pre-heater or a complete replacement of your engine, depending on the issue. 

Black Diesel Smoke

Black smoke, also referred to as “rolling coal,” could have several causes that you may want to look into. Let’s go over some common causes of black smoke and how to fix it. 

Causes of Black Smoke From Diesel Exhaust

A little black smoke is normal on a properly functioning diesel — in fact, some diesel owners add larger injectors to create more black smoke. However, it’s a good idea to keep an eye on the amount of black smoke at different RPMs and loads so that you will be able to tell if something is amiss.

Incorrect timing or air/fuel ratio, dirty injectors or common rail injectors staying open for too long, a worn turbocharger, dirty intake manifold or clogged air cleaner, low cylinder compression, poor quality fuel, or excessive carbon build up in the combustion chamber can all be common culprits.

How Do You Stop Black Smoke From a Diesel Engine? 

Stiction Eliminator is a great place to start when trying to get rid of black exhaust smoke. It will make sure the turbo internals, camshaft, and HEUI injectors are cleaned and lubricated. It can help restore compression, ensuring that the combustion chamber is at optimal performance. 

For other situations, a dose of Diesel Extreme might be what you need to clean out those injectors coked with burnt fuel and get them firing like new. It’s also an excellent solution to use to clean the fuel system while simultaneously maximizing performance.

You can also try replacing your air filter, checking the intake manifold out, or fiddling with your aftermarket tuner. Be sure to ask a professional if you have little experience with these replacements. You should also keep in mind that running rich — having too much fuel — is always better than running lean — not having enough fuel. A lean air/fuel ratio can damage an engine in a short amount of time and can sometimes be the cause of black smoke from your diesel engine. 

Eliminate Smoke From Your Diesel Engine With Hot Shot's Secret

Eliminate Smoke From Your Diesel Engine With Hot Shot’s Secret 

At Hot Shot’s Secret, we understand that identifying the causes of smoke from your diesel engine can be tricky. That’s why our team is dedicated to providing you with high-quality products and solutions to help you eliminate smoke and treat the causes so it doesn’t come back. All of our products are backed by science and come with a money-back guarantee, helping you to narrow down the causes of smoke from your engine and potentially saving you money in the long run. 

Start shopping our products online today to help reduce common engine problems and increase the longevity of your vehicle. Do you have any questions? Get in touch — we’d be happy to help.