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What is Black Diesel? The Complete Guide

Hey friend! Have you heard of black diesel and wondering what exactly it is? In short, black diesel is an illegal alternative fuel made from mixing used oils into regular diesel. It produces thick black smoke and major engine damage while releasing tons of harmful emissions.

Let me explain further…

As a fellow auto enthusiast, I‘ve researched diesel exhaustively. In this comprehensive guide, I‘ll share insider knowledge on what black diesel is, why it‘s problematic, and how to properly care for your diesel engine.

Black Diesel Fuel Explained

Black diesel refers to regular diesel fuel mixed with used motor oil, transmission fluid, crankcase oil, or other waste petroleum products. This gives it a characteristic black color. It‘s sometimes called waste oil diesel for this reason.

Legally, black diesel is not an approved automotive fuel since it does not comply with emissions regulations when used on-road. The high content of unburnt carbon and particulate matter in black diesel exhaust makes it illegal.

Yet some diesel truck owners experiment with making and using black diesel fuel to purposefully "roll coal" – blowing ostentatious black smoke. But this comes at a cost…

Key Stats on Black Diesel Emissions

The EPA estimates black diesel exhaust contains over 40 times more particulate matter than standard diesel exhaust.

In fact, just one dump truck burning black diesel emits as much particulate matter as 60 new diesel trucks.

Particulate pollution from black diesel is linked to over 10,000 premature deaths annually in the U.S. alone, according to an MIT study.

Clearly, black diesel has an outsized impact on air quality and human health despite limited use. But why exactly does it create so much pollution?

Why Black Diesel Smoke is So Toxic

The black color comes from unburnt carbon – soot and particulates that form when the fuel burns incompletely.

You see, used motor oil alters the combustion dynamics inside the engine. The contaminants in the oil prevent thorough fuel atomization and full combustion.

More carbon ends up discharged as black smoke instead of fully converting to CO2. This also releases more air toxins like benzene, sulfur, and nitrogen oxides.

In contrast, high-quality ultra-low sulfur diesel burns much cleaner with far fewer emissions.

The Chemistry Behind Black Diesel

Used motor oil contains compounds like:

  • Unburnt fuel residues
  • Metallic additives like zinc, calcium, and magnesium
  • Soot and particulate matter
  • Acids and other degradation compounds

When mixed into diesel fuel, these impurities alter the fuel‘s cetane rating, viscosity, lubricity, and ignition qualities – creating a dirtier, less stable combustion.

The metallic additives can also foul injectors and catalytic converters when burned, reducing engine performance further over time.

Black Diesel vs Biodiesel

Some confuse black diesel with biodiesel made from vegetable oils. But biodiesel is a cleaner-burning approved fuel when properly produced to specifications like ASTM D6751.

Biodiesel contains no toxic impurities – just plant-derived fatty acid methyl esters that burn similarly to petroleum diesel when catalyzed into fuel.

So biodiesel is a legal, renewable fuel, while black diesel is an illegal waste oil mixture.

Black Diesel Health Effects

Inhaling black diesel exhaust is extremely hazardous. The microscopic soot particles penetrate deep into lungs:

  • Causes inflammation and lung damage
  • Triggers asthma attacks
  • Linked to lung cancer, stroke, heart disease, and premature death

Young children and the elderly are most vulnerable to diesel particulate exposure according to Mayo Clinic researchers.

There‘s no safe level – even small amounts increase health risks. That‘s why avoiding black diesel smoke is critical.

The Environmental Impact

The illegal use of black diesel also harms our shared environment:

  • Produces over 40 times more particulate emissions than legal diesel fuel
  • Toxic air pollution causes smog, haze, and acid rain
  • Soot released contributes to climate change
  • Improper waste oil disposal contaminates soil and water sources

Based on lifecycle analysis data, black diesel generates up to 15% more CO2 emissions than petroleum diesel when the full waste stream is considered.

Is Black Diesel Fuel Legal?

Let‘s be clear – using black diesel on public roads is completely illegal in the U.S. under the Clean Air Act.

Anti-tampering laws strictly prohibit any fuel or modification that increases vehicle emissions above certified levels.

Fines can reach $3,750 per violation per day in the case of a federal EPA crackdown. State and local penalties may also apply.

Plus, black diesel enables fuel tax evasion since no road taxes are paid on the waste oil components. This theft costs governments billions in lost revenue.

The only lawful use is in certain off-road vehicles on private land in most areas. Public road use will get you in legal trouble quick.

Black Diesel Engine Damage

Unfortunately, black diesel doesn‘t just harm the environment and your lungs – it also damages your engine:

  • Fuel injector corrosion and coking
  • Fuel pump wear from poor lubricity
  • Combustion chamber deposits
  • Ring sticking and cylinder glazing
  • Premature engine wear
  • Filter/injector clogs from particulates

Over time, these issues lead to lower power, higher emissions, and degraded fuel economy.

The unburnt fuel residues also dilute and contaminate your oil. This accelerates engine wear dramatically.

Trust me, saving a few bucks on diesel isn‘t worth ruining your expensive engine!

How Black Diesel is Made

Though illegal, underground enthusiasts mix black diesel using:

  • Waste motor oil, transmission fluid, crankcase oil, etc.
  • Settling/heating to remove some contaminants
  • Blending with diesel fuel at 5-50% ratios

No filtration or chemical conversion takes place – just crude mixing of waste oils with diesel.

Don‘t be tempted by "homebrew" black diesel recipes online. Stick with legal fuel sources only.

Maintaining A Healthy Diesel Engine

Instead of black diesel, keep your diesel running smoothly by:

  • Using ultra-low sulfur diesel only
  • Replacing fuel filter every 10k miles
  • Installing a quality air intake system
  • Regular oil changes per manufacturer spec
  • Annual injector cleaning service
  • Tuning and upgrades to improve efficiency

This comprehensive maintenance prevents issues like smoking, knocking, and power loss.

Your engine will last years longer while maintaining near-peak performance. It‘s worth the modest investment.

The Verdict on Black Diesel

Hopefully this gives you a deeper understanding of what black diesel fuel is all about. While some see it as harmless fun, in reality it has serious consequences for health, environment, and engine longevity.

Do yourself and your vehicle a favor – steer clear of black diesel entirely. Instead, use only legal high-quality fuels and practice diligent maintenance habits. Your diesel engine will run smoothly for miles to come.

Let me know if you have any other diesel-related questions! Happy motoring.