Decoding Why Your Diesel is Smoking

While a little puff of black smoke under heavy acceleration is often considered normal, persistent or differently colored smoke can indicate serious underlying issues.


The color of the smoke is your first clue to the problem.

  • Black Smoke: This is the most common type of diesel smoke and usually indicates incomplete combustion.


  • EGR (Exhaust Gas Recirculation) Problems: A malfunctioning EGR valve can cause excessive black smoke.


  • White Smoke: This often indicates unburned fuel or coolant in the combustion chamber.

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  • Low-Quality Fuel: Water contamination in the fuel can also produce white smoke.


  • Blue Smoke:This usually indicates burning engine oil.


  • Overfilled Engine Oil: excess oil can be forced into the combustion chamber.


Observe the Smoke: Note the color, density, and when it occurs.

  • Fuel Filter: A clogged fuel filter can cause fuel delivery issues.
  • Engine Oil Level: Ensure the oil level is correct.
  • Coolant Level: Check for any signs of coolant loss.


Preventive Maintenance:

  • Regular Oil Changes: Use high-quality diesel engine oil and change it according to the manufacturer's recommendations.
  • Air Filter Replacement: Replace the air filter regularly to ensure proper airflow.
  • Fuel Filter Replacement: Change the fuel filter as recommended to prevent fuel contamination.
  • Glow Plug Maintenance: Check and replace glow plugs as needed, especially in cold climates.
  • Injector Cleaning: Consider periodic fuel injector cleaning to maintain proper fuel spray patterns.
  • Turbocharger Maintenance: If your diesel engine is turbocharged, follow the manufacturer's recommendations for turbocharger maintenance.


Give us a call and let us take care of you.

Happy Adventures,

Heather


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By jhautoinc January 30, 2026
These are vital to keep you safe on the road.
By jhautoinc January 27, 2026
Your engine will thank you.
By jhautoinc January 23, 2026
They help keep your engine cool.
By jhautoinc January 20, 2026
They need maintenance to keep them running.
By jhautoinc January 17, 2026
It's better for your engine. 
By jhautoinc January 13, 2026
They are more important than you know.
By jhautoinc January 10, 2026
A spark plug gap can cause a misfire.
By Bobby Poist January 7, 2026
They're important to keep you safe on the road.
By jhautoinc January 3, 2026
It's more often than you think.
By jhautoinc December 31, 2025
Batteries really don't like cold weather