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Why Is My Tractor Smoking? (Troubleshoot Guide)

“Oh my Gosh!, why Is my tractor smoking?”

A week ago, I was out to the field with my tractor when I noticed some smokes puffing out, and to many dismay, I wasn’t worried, at all, this is not to see that tractor smoking isn’t an indicator of any underlying issue. The danger of a tractor smoking depends on the color of smoke that puffs.

Why your tractor is smoking?

There are many reasons why your tractor smokes, there is no one reason. The color of the smoke determines what is happening to the tractor.

They are three colors that are associated with tractor smoking, and they are:

  • Black smoke
  • White smoke
  • Grey/Blue smoke

Black Smoke

The most common tractor smoke is black smoke. Whenever you notice your tractor churning out black smoke, this means the presence of an imbalance in the air-to-fuel ratio in the machine. It is either you add too much fuel, or insufficient oxygen has been put to burn the fuel.

I advise that your look at the smoke observantly, especially if it is the black smoke. I can remember a time when my tractor is churning out black smoke, I came down from the tractor to observe the smoke, and I saw that the smoke was full of particulates, with a more careful look,  I discovered that they are leftover from the diesel fuel that has not been properly burned.

Normally, if your engine functions properly, the exhaust it produced is usually a combination of water and carbon dioxide.

I want you to understand that diesel fuel is chemically made up of long chains of carbon molecules, and these molecules are broken down through the combustion process. If something goes wrong in the combustion process, it simply means that the engine won’t be getting the maximum power and fuel mileage, as such producing black smoke

Causes of Black Smoke

Dirty or Clogged Faulty Injector

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A dirty or clogged injector can lead to a loss of power, and the production of black smoke. The fuel injector functions to supply your diesel engine with fuel, by spraying it into the engine’s cylinder via a nozzle to begin the combustion process. So for the black smoke to be avoided, the injector should be confirmed that it is working properly.

Bad Air Filter

The combustion process involves the diesel fuel and air to function properly. If the engine isn’t getting enough air, it could result in the production of black air.

If the air filter is clogged and dirty, it can prevent enough air from getting into the filter, thereby causing black smoke.

Faulty Injector Pump

The pump is a part of the injector that injects the fuel into the combustion chamber in the form of a spray. But when it is faulty, it cannot perform this function.

Also, when the fuel is dirty, it causes a residue to build up within the fuel system. This can interfere with the functioning of the injector pump.

Bad Turbocharger

The turbocharger is a compressor located on the exhaust side of the vehicle that helps to enhance the horsepower of your tractor. Also, it leads air into the engine as the EPM goes up. So if you have a bad turbocharger, the power of your tractor will decrease, and this is will lead to black smoke.

Ensure your check your turbocharger daily for optimum performance.

Faulty Exhaust Gas Recirculation (EGR) Valve

The Exhaust Gas Recirculation (EGR) valve helps to improve your engine’s performance, including the economy; what it does is allow exhaust gases to flow back through the cylinders to be burned again, lessening the rate of emission.

When your EGR is faulty or malfunctioning, the air-to-fuel ratio gets off, which you already know is true because of the black smoke. Generally, there will be reductions in fuel efficiency, accelerations, and overall power of the engine.

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If this is the case, you will need to have the EGR valve replaced.

Sometimes the EGR may be filled with some carbon deposits, and this can impede the functioning of the EGR.

Also, I will advise you regularly change the tractor oil as it helps to reduce the amount of sludge accumulated in the engine.

Other causes include:

  • Plugged crankcase ventilation system,
  • Inaccurate valve adjustment,
  • Faulty injectors,
  • Malfunctioning atmospheric pressure sensor,
  • Leaking turbocharge oil seal,
  • Faulty automatic timing advance

Why does your tractor blow white smoke?

Why I wasn’t worried about the smoke is because it was white smoke? Are white smokes less dangerous? Not though. From experience, which is also backed up with facts, most modern diesel tractors do experience white smoke at startup. However, this disappears immediately when the engine is done warming up.

Older mechanical pump-line-nozzle (PLN) engines also bring out white smoke when the engine is a startup, but it takes a longer time for the smoke to disperse.

However, if the engine continues to churn out white smoke profusely, this can be an indication of misfiring cylinders that can be caused by malfunctioning injectors.

Other causes of excessive churning of white smoke could are:

  • Malfunctioning coolant temperature sensor.
  • A plugged crankcase breather.
  • Bad/Poor-quality fuel /incorrect fuel grade.
  • Air in the fuel system is caused by loose fittings.
  • Faulty atmospheric pressure sensor.
  • Faulty/malfunctioning  cylinder/piston rings
  • Filling in excess engine oil beyond the normal average as shown in the dipstick
  • Damages to the breather tube (the one located behind the air filter)

Tractor spitting out Grey/Blue Smoke

Unlike white and black smoke which is usually related to fuel problems, blue smoke is a perfect sign that your engine is burning excessive oil. This isn’t a serious problem, so it is no cause for alarm.

When you notice that your engine is churning out blue smoke, do check the piston rings, because if the piston rings are broken or faulty, it might result in the engine burning excessive oil. Also, do check the liners or valve guides, as they can also contribute to the blue exhaust when in a faulty stage.

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Other causes of blue smoke are:

  • A leaking turbocharger seal
  • A restricted turbocharger drain line
  • High crankcase pressure

How to Troubleshoot A Smoking Tractor

Are you using the tractor at more than a 15-degree angle? You have to immediately, as it can lead to the production of blue exhaust in your tractor.  

Also, avoid tilting your tractor, mower, or equipment, as it can cause leaks.

Before using your tractor:

  • Check and change the oil
  • Regularly check if the oil is the right grade/type
  • Regularly check if the oil to ascertain it is in the right proportion 
  • Check the crankcase for leaks or faults
  • Check the head gasket functionality
  • Check the rings and cylinder for tears or wear.

Also, one thing I do to ensure my tractor is always functioning properly is to service the tractor regularly, through servicing, you can easily detect minor wear and tears before it gets serious.

Also, tractors have peculiarities, so ensure you read your tractor manual or manufacturer guide to understand the functioning and operation of your tractor.


You should not treat any form of smoke as likely, as it can be an indicator of any underlying issues in the tractor.

In the case that you can’t lay your hands on the exact cause of the smoke, you can consult a tractor mechanic, or take your tractor to a repair shop.

Mark Lockett

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