Causes of Blue Smoke from Exhaust When Accelerating and How to Fix

Are you looking for the causes of blue smoke from exhaust when accelerating? Usually, Blue smoke is an alarming sign, and it indicates oil leakage in the engine. Most exhaust gases are not visible. However, when the vehicle engines face any problem, its symptoms are visible in different color exhaust smoke, noises, and car performance.

Generally, color emission from the exhaust indicates a different problem in the car engine. White, Blue and black color emission from the exhaust is not a good sign. Usually, Blue smoke indicates oil leaks inside the car engine and white exhaust smoke indicates coolant leakage. There are many ways to fix exhaust gas problems. Blue color emission from the exhaust requires an urgent fix.

This article will guide you on the causes of blue smoke from exhaust when accelerating and how to fix it.  Before going to more depth, let’s discuss what blue smoke from exhaust indicates?

blue smoke from exhaust

 What blue smoke cloud indicates?

you notice odd noise and blue smoke coming from the exhaust, it indicates oil leakage in the engine. If an automobile is maintained properly, these problems don’t appear. Regular maintenance is important for the well-being of the car engine. If blue smoke appears from the exhaust, it should be taken seriously. If the problem exists for a long time, it causes permanent damage to the engine. Moreover, the quicker the diagnosis, the sooner the problem gets solved. Mechanics believes if blue smoke appears, you should stop driving at once.

Blue smoke appears from the tailpipe in two situations

  1. When engine starts
  2. When car accelerates

What causes blue smoke from the tailpipe when starting?

Blue exhaust smoke is the rarest smoke emitting from a car engine. The occurrence of blue smoke indicates burning oil. Generally, blue smoke is common when you start an engine in cold weather. In the cold season, the engine oil gets thinner and sometimes escapes into the cylinders of an exhaust system. The escaped oil burns in the combustion chamber, causing blue emission and glow red exhaust manifold.

Oil reduction or lack of lubrication causes wear and tear in different parts of the engine. Furthermore, these worn parts cause damage to the engine. The blue smoke on startup indicates three things.

  1. Oil leakage in the combustion chamber
  2. Damaged piston ring
  3. Worn out cylinder head valve

Causes of blue smoke from exhaust when accelerating

 If you notice color emission from a good exhaust pipe when you accelerate. It is a reason to worry about. Generally, color smoke indicates a serious problem with the engine. If you notice blue smoke coming out of your tailpipe when accelerating. These should be the reason.

  1. Crack in the ventilator valve
  2. Damaged piston rings
  3. Transmission fluid leakage
  4. Blown turbo
  5. Damaged valve seals

1. Crack in the ventilator valve

One of the reasons for blue smoke is a crack in the ventilator valve. Usually, the ventilator valve releases pressure in the exhaust manifold. If there is a crack in the valve, it will get stuck. This allows oil, air, and fuel to mix inside the engine. This mixing causes blue emission from the exhaust when accelerating.

2. Damaged piston rings

Blue smoke during acceleration indicates damaged piston rings. Generally, every car has a piston that moves in the cylinder. Piston rings prevent the piston from hitting the cylinder walls. These rings form a seal around the cylinder. However, the damaged piston ring cause oil leakage in the engine. Oil mixing causes blue smoke.

3. Transmission fluid leakage

Transmission fluid is responsible for the system operation and performance of the car. It lubricates the mechanical parts and prevents them from rusting. Generally, the TCM acts as a sensor and monitors the transmission fluid. If the automatic transmission fluid system is damaged. It causes transmission fluid to enter into the engine and burn like oil. Thus, it causes blue smoke from the exhaust.

4. Blown-out turbocharger

A blown-out turbocharger is also a reason for blue smoke. A turbocharger causes an increase in engine power and output. Typically, a broken turbocharger is identified by a damaged oil seal. If the seal is broken or damaged, the oil in the engine enters combustion chambers. The mixture of burned oil and fuel causes blue smoke.

5. Damaged valve seals

Generally, valves serve two main purposes. The first is to allow gasoline and air into the engine. Secondly, is to release exhaust gasses out. Frequent lubrication prevents valves seals from wear and tear and improves operations. However, when seals get damaged, the oil escapes and enters the combustion chamber. The result of oil and fuel causes blue smoke.

Causes of blue smoke diesel engine

Usually, diesel and gasoline engines have many similarities. However, they are some differences. One of them is a glow plug. In a diesel engine, a glow plug ignites the fuel. If the glow plug is damaged, it causes blue smoke while starting. In diesel engines, blue smoke indicates burning oil. It is caused by

  1. Increased engine oil level
  2. Damaged piston ring
  3. Damaged cylinder

How to fix blue smoke coming from the exhaust

Blue smoke coming from exhaust means burning oil, and the reason is described above. Let’s see how to solve these problems.

1. Engine clean

Sometimes lack of regular maintenance causes oil to reach the combustion chamber. This causes clogged cylinder heads and valves. Deep cleaning of dirt in the cylinder head. Can remove the blue smoke problem. Moreover, cleaning of clogged valves and reassembly doesn’t require any professional help.

2. Replacement of ventilator valve

Fixing a ventilator valve or PCV Valve is easy and inexpensive. For replacement, search for a tube that connects to the Intake Manifold. At the end of the tube, you will find PCV Valve. Now replace the old PCV Valve and with a new one. Moreover, it will solve the problem of blue smoke.

3. Repair or Replacement Transmission Modulator

The first step towards the replacement of the transmission modulator is to identify its location. Secondly, replace the transmission modulator. Sometimes the vacuum line is damaged by transmission fluid. So, the whole line should be replaced. Besides, you should fix exhaust leakage if you notice.

4. Replace blown-out turbocharger

For replacement of turbocharger, professional help is required. Usually, broken turbochargers break into smaller pieces. These small pieces can enter the engine and cause permanent damage to the engine. Moreover, if the problem is a broken turbocharger, you should not drive the car.

5. Replacement of Valve seals 

Replacement of the Valve seal is time taking process. However, someone with knowledge of engines can easily do it. Generally, Valve is attached to the spring and rocker arm. Remove the spring and replace the old Valve. For bringing the valve spring out, valve spring compression tools are available. When the valve spring is out, you can easily access the valve seals.

To remove the valve seal, pull out the top of the valve stem. Then replace the old with a new one. After putting the new seal on the top of the valve stem, reassemble everything back.

6. Replacement of piston rings

To access the piston ring, remove the cylinder head. The cylinder head is hard to disconnect because you have to disconnect many things like intake manifold, spark plugs wires, and distributor. After the disconnection of the cylinder head, clean the piston and remove the old piston rings. Install new piston rings and reattached the cylinder head.

 FAQ (blue smoke from exhaust)

1. Is blue smoke from exhaust bad?

Yes, blue smoke from the exhaust is a bad sign. Generally, it indicates oil leakage in the engine. You should take it seriously, because it can cause serious damage to the engine.

2. Does Blue smoke mean blow head gasket?

No, blue smoke indicates oil leakage in the engine. Normally, white or grey smoke indicates a coolant leak in the cylinder. This leads to a blown head gasket. However, if there is oil leakage in the gasket the blue smoke is an indication.

3. How much does it cost to fix blue smoke from exhaust?

Blue smoke is due to oil leakage, and the reason behind this is damaged glow plugs, valve seals, piston rings, or PCV valves. Generally, if you know the engine, it can take time but it is cost-effective. However, it can cost between 80 $ to 500 $ depending on the problem if you don’t know. Moreover, if the problem is with the piston ring is can cost up to 7000$.

4. Can low oil cause blue smoke?

Usually, blue smoke is because of oil seeping into the engine. Leakage causes an engine to have low oil. Oil leakage can cause oil dripping in the exhaust system as well.


The problem of blue smoke from the exhaust when accelerating is serious. Generally, it is because of burned oil. The reason that causes oil leakage includes damaged glow plugs, valve seals, piston rings, or PCV valves. However, it takes time to find the root cause of the problem this problem.

If you don’t have information about the engine, it is better to consult a mechanic before taking any step. Thus, it is essential to know the causes of blue smoke from exhaust when accelerating and how to fix the issues.


Shafiqule Islam is a graduated Mechanical Engineer. He has both on hand and managerial job experience of 15 years in automobile maintenance field. He served as Captain in Electrical and Mechanical Engineering Corp of Army, Technical Head in Taxi Cab business, Head of Plant in Car assembly plant. He is writing automotive contents to share his expertise knowledge to car lovers for solving their vehicle issues.

Recent Posts