Cause and Solution | Why is My Duramax Blowing White Smoke?

When the temperature in the combustion chamber is too low, it causes white smoke from the exhaust of a diesel engine.

Blowing white smoke from your vehicle exhaust is a serious problem.

Diesel engine emits three different colors of smoke, white, blue, and black.

In this article, I have described the cause with the possible solution for different colors of smoke in Duramax.

Check out other problems with the Duramax engine:

What Does White Smoke from Diesel Exhaust Mean?

When your vehicle exhaust emits white smoke, it indicates that the fuel is not burning properly.

It means the engine is too cold.

There are 03 different types of white smoke releases from the exhaust.

  1. White smoke in cold weather disappears when the engine warms up
  2. A thick cloud of white smoke
  3. Continuous light white smoke.

Why is Duramax Blowing White Smoke?

06 factors cause the white smoke.

Among them, clogged fuel filters, faulty injectors, and transmission fluid leakage are the most common cause.

01. Faulty Injector

Faulty Injector

Mismatched injection time may cause engine explosives.

As rust particles easily contaminate the diesel engine injector, it blocks the spray tip, which causes injector closing problems.

Because of the contamination, the injecting time is affected and results in an inappropriate air-fuel mixture in the combustion.

It causes the white smoke from the exhaust.


Sometimes, cleaning will work, but replacing is the better option for a long-term solution.

02. Clogged Fuel Filter

Clogged Fuel Filter

When the fuel filter is clogged, it causes unfiltered fuel to pass into the engine, leading to an inappropriate air and diesel mixture in the combustion chamber.

When air and diesel burn simultaneously, it produces white smoke emitted from the vehicle exhaust.

That is how clogged fuel filters also cause engine misfires and stalling.


Cleaning the clogged fuel filter may solve the problem.

If the fuel filter becomes too dirty, replace it.

A fuel filter costs around $10 to $60 without labor costs.

03. Blown Head Gasket

Blown Head Gasket

A blown head gasket contaminates the fuel-air mixture and causes white smoke.

Engine crack or leak in the head gasket results in emitting white smoke from the exhaust.

But a cracked engine is rare because the head gasket seal is designed, so the block doesn’t have an issue until the head gasket has a problem.


Replacing the head gasket is costly ($1500-$2000), so repairing it will be the better choice.

Hire a mechanic to repair the blown gasket; otherwise, it may lead to new problems.

04. Leaking of Transmission Fluid

Leaking of Transmission Fluid

Leaking of transmission fluid causes white smoke from the exhaust.

A strong, pungent smell comes out when the fluid is combusted, which is the main sign of leaking transmission fluid.

The fluid leaking occurs for different reasons like

  • Seals not tightened properly
  • Cracks in the transmission seals
  • Gasket’s wear and tear
  • Faulty diaphragm valve
  • Overheating etc.


Check the seals and gasket.

Tighten the gasket and seals properly if needed.

Replace the excessively damaged parts.

05. Malfunction of Fuel Injector

The fuel injector ensures that fuel is transmitted into the combustion chamber at the right time.

A malfunction in the fuel injector fails to do the fuel transmission process at the time and produces white smoke.


Various reasons cause fuel injector malfunction.

First, identify the actual problem and solve it.

It will save you from unnecessary expenses.

06. Faulty ECU

Faulty ECU

A faulty Engine Control Unit (ECU) affects the fuel injector timing.

Sometimes, fuel injectors have no problems, but it miscalculates fuel injection time because of faulty ECU.

Indirectly it causes white smoke.


Reprogramming may solve the problem.

If not, it needs extra treatment to fix a faulty ECU.

Why is Duramax Blowing Blue Smoke?

Blue smoke blowing from the exhaust is a rare type of problem.

It is a sign that oil is burning.

However, it will be expected if you start your engine in too cold weather.

07 Causes of Blue Smoke:

  1. Faulty piston rings
  2. Worn guides
  3. Too much oil in the engine
  4. Worn cylinder
  5. Damaged lift pump
  6. Bad-graded oil
  7. Oil and fuel mixture etc.

Why is Duramax Blowing Black Smoke?

Black smoke is the most common color emitted from a diesel engine.

It mainly indicates that something is wrong with the diesel fuel combustion system.

08 Causes of Black Smoke:

  1. Clogged air cleaner
  2. Incorrect injector timing
  3. Faulty injector pump
  4. Faulty intercooler
  5. Worn valves in the cylinder head
  6. Inappropriate valve clearance
  7. Damaged piston ring
  8. Damaged EGR cooler etc.


01. Can Bad Fuel Causes White Smoke?

Yes, bad fuel causes white smoke.

Pour the fuel into a clear glass container to check the fuel condition.

If there is any mixture in the fuel or if the fuel is contaminated, they will be separated in the clean glass.

02. What Causes White Grey Smoke?

A white-grey smoke mainly emits when transmission fluid burns.

It is most common in a diesel engines.

03. Is It OK to Drive with White Smoke?

No, it caused severe problems like overheating.

So, stop driving your vehicle when you find the such problem and take the necessary steps ASAP.

04. Why Does My Diesel Smoke when I Accelerate?

Damaged engine piston rings are the most common reason for smoke when accelerating.

So, check the engine piston rings and repair them.

Final Words

The Duramax diesel engine should not produce any smoke if appropriately maintained.

The reason for white smoke is challenging to identify sometimes, but if you follow the steps mentioned in this article, you can easily find the actual cause.

Stop the vehicle if you notice any symptoms to avoid more damage.

According to the recommendation, take the necessary steps to eliminate the white smoke issue.

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