Blue Smoke from Exhaust (Causes & Fix)

Do you always notice blue smoke coming from your car’s exhaust pipe? Do you know what it might mean?

If you want to investigate the potential causes of blue smoke from a car’s exhaust and the finest methods to resolve the situation before it worsens, you’re in the right place where all these will be discussed.

Blue exhaust smoke is not a comforting sign. When there is an alternative color of exhaust smoke other than something light-colored or thin white that resembles water vapor from a car’s exhaust, it’s a clue that there is an issue.

This issue is directly tied to the engine’s combustion system and could be harmful if not resolved immediately.

We have analyzed some of the causes, and they all points to one thing, your engine oil is burning with the fuel. In this article, you’ll learn about things that cause blue smoke, the steps you can take to address them, and what it might cost you. Also, some Frequently Asked Questions are answered at the end.

Let’s get started!

When oil and gasoline are combined during combustion, it results in blue smoke, and oil spilling onto heated engine components is another potential cause. Blue smoke may occasionally indicate that a component, such as a PCV (Positive Crankcase Ventilation) valve or turbocharger, has failed.

When blue exhaust smoke is visible, it means the oil in your engine is burning, leaving the exhaust vent and the fuel that has been consumed. Whatever the cause, the car must be fixed because it isn’t running well.

Blue Smoke from Exhaust

Blue Smoke from Exhaust Causes

Oil is Dripping Onto the Headers

As previously discussed, your drivetrain’s hot exhaust components may get contacted by oil that has escaped from your gasket between the engine block and head. This will result in the appearance of blue smoke and a strong odor.

You might detect blue exhaust fumes behind your vehicle as you accelerate or while the engine is idle.

Oil Mixes With Fuel

Back to the blue smoke, your car’s PCV valves, valve seals, and piston rings will eventually wear out. Additionally, if you drive your car ten thousand miles between engine oil swaps, the engine oil won’t be as effective at lowering motor friction.

As a result, the engine will produce more heat, which heats and cools the gaskets, thereby causing the gaskets to dry up and break.

As a result, you might find that your oil will mix with your gasoline and the bi-product oil ends up being burned well inside the engine’s combustion chamber. Dry and damaged valve seals are ineffective at keeping fluids apart.

This indicates that there will now be some blue smoke from the exhaust system when only grey smoke leaves the exhaust pipe on a typical day. You must replace your engine if the piston rings become worn out.

It’s possible you put in too much oil if the blue smoke only started showing after an engine oil change. As a result, the oil will scum up and become less effective at handling heat and lubrication. Drain the extra oil, then restart.

Also Read: Car Blowing White Smoke After Oil Change

Oil Drips Onto Hot Engine Parts

Here’s another scenario: Your engine leaks a small amount of oil when the valve cover gasket or head gasket fails. That engine oil will spill onto other hot engine bay components (such as your headers) before evaporating in a billow of blue fumes.

When your car is idling, the smoke will first emerge from under the hood; then, while driving, it will emerge from the back. This is another reason you should always be aware of the scents emerging from your car.

Is there a burning scent in the air? Was that odor present earlier? Was there a cheeseburger left in the glove box? Ask yourself these kinds of questions.

Faulty Glow Plugs (Diesel Engines)

Your glow plugs are damaged if you detect black or blue smoke emanating from the diesel truck or car when it first starts up. As a result, your automobile won’t start regularly, and you can experience a lengthened cranking time.

Connect a 12v test indicator light to the positive battery terminal to see if your glow plugs are the cause of the issue. Next, attach each wire to a different glow plug to check if you can get a reading.

If you decide to do it yourself or hire a professional technician to do it for you, replacing them might cost somewhere between $100 to $500, so it’s important to ensure they are damaged before you spend that much money.

Turbocharger is  Blown

Blue smoke from the exhaust indicates that the turbo must have blown. Blue smoke can be caused by a blown turbo or an oil seal leak. Either way, there is an oil leakage into the engine. Blue smoke is produced when oil and fuel combine inside the engine.

Damaged Piston Ring 

Piston rings were developed to keep engine oil in a combustion chamber where it belongs. If they malfunction, the engine oil can spill in the wrong place.

Smoke in this color may be produced as the engine oil and fuel combine. Regrettably, piston ring replacement can be very costly.

Jammed PCV Valve

Additionally, the PCV valve might result in blue exhaust smoke. The pressure accumulating in the engine oil pan is released via this valve. The intake manifold is under pressure so that exhaust smoke can be burned again.

The oil combines with other gases and air when the Positive Crankcase Ventilation valve is jammed. Blue smoke may result from the intake manifold’s connection to your air filter.

Blue Smoke from Exhaust

How to Repair Blue Smoke from Exhaust

Decamp Excess Oil

Removing excess oil from the system is the easiest repair. This solution only functions if completing an engine oil change immediately precedes the blue smoke.

The system may have too much oil. Because of the pressure and aeration this state creates, the engine has difficulty effectively managing friction and heat. Remove enough oil to restore the proper levels to fix the problem.

Make the Engine Clean

It’s time to look at the engine if it has been a while since it has been serviced. The engine oil return apertures within the cylinder head might become blocked by dirt lodged in the engine, leading to a leak.

Take off the valve cover, then clear it of any visible debris. Additionally, it would help if you cleaned the drain back holes. Ensure no oil is left on the engine that could lead to blue smoke by wiping it down.

Inspecting the engine while you clean it off is a good idea. If you see a spot where oil may be dripping, take urgent action to address the issue.

Change Piston Rings

Damaged piston rings can produce blue smoke; however, this is a complex issue to solve.

Even though the piston rings might only cost $50 each, the labor drives up the cost. To access the rings, the engine must be taken apart before the work can be done. This would require a budget of about $1,000 or more.

Repair Turbocharger

If the turbocharger blows, you must immediately stop driving. Driving a vehicle with a burst turbo can result in much more serious issues.

The lack of lubrication in the turbocharger allows metal pieces to develop. This metal has the potential to enter the engine, causing long-term harm.

Change PCV Valve

The PCV valve replacement is simple and inexpensive. To locate the PCV valve, find the tubing that connects the intake manifold to the valve cover and follow it.

Remove the valve and install a new one. Everything will function as it should as long as the replacement valve is installed in the proper location, perhaps also resolving the blue smoke issue.

Fix Valve Seals

It would help if you didn’t attempt to replace the valve seals unless you possess some mechanical understanding of cars. You will require a few specialized tools and considerable dexterity to do the task correctly.

You must remove the spring from the rocker arm and valve to replace the valve seals. Replace the worn valve seal by raising it. Be careful not to drop the valve into the engine. Otherwise, you’ll be dealing with a much worse issue.

Should One Still Drive With Blue Smoke From exhaust?

Blue smoke from your exhaust pipe won’t stop you from driving, but we advise you to take your automobile to a professional technician as soon as possible. This is because fuel and oil mixing is terrible for your engine and was not intended to happen.

You will need to replace your engine if your piston rings are worn out and your car has a high mileage; this may cost you between $2500 and $7000, which you do not want to spend. If you see blue smoke, have that problem looked at immediately because you might only need to replace the piston rings and keep driving for a few more years. You want to avoid replacing your engine.

The Cost of Repairing your Blue Smoke Problem

Depending on the issue, you will need to change your glow plug, head gasket, valve seals, piston rings, or PCV valve.

A valve seal typically costs $40, so if you have some time and are skilled with a wrench, this might be a relatively inexpensive fix. You could also use your spare car while working on the problem.

If you have little mechanical skill, the part will cost you $80 from a shop, plus $500 or more for labor. It’s somewhat pricey but less costly than a totaled vehicle or a replacement engine!

The challenging part is that if your piston rings are damaged, your engine will most likely need to be replaced. This job is very expensive and may cost up to $7000.

Make sure to inquire at the dealership if your vehicle is somewhat new since this should be included under the warranty powertrain. You might have to hold your tongue and pull out the wallet if the value of the secondhand car is more than the cost of replacing the engine. This tale of the mythical blue smoke may end at that point, as most individuals and insurance agencies consider changing an engine a total loss.

Also Read: Car Blowing White Smoke After Oil Change

Frequently Asked Questions – Blue Smoke from Exhaust

What causes blue exhaust smoke?

Initially, blue exhaust smoke can frequently appear to be gray smoke. However, a pronounced bluish hue could indicate that your engine consumes a lot of oil. This can result from worn engine parts like Positive Crankcase Ventilation (PCV) valves, PCV seals, or piston rings.

Does Blue smoke mean a blown head gasket?

There is a good chance that the issue is with the head gasket if your automobile has a sort of rocket-ship appearance and blue smoke is coming from the exhaust. Oil is possibly burning inside the cylinders due to leakage.

What causes blue smoke from the exhaust when accelerating?

Leakage through the engine valve seals that allow oil to enter the combustion chamber and burn alongside the gasoline is typically the cause of blue smoke from an automobile’s exhaust pipe. This can be a result of a broken component or natural degeneration.

Can low oil cause blue smoke?

An oil leak into the engine cylinders can result in spark plug fouling, rough idling, and misfires. Additionally, a decrease in engine performance and oil loss may indicate that the source of the blue fumes is an engine parts oil leakage.

Can too much fuel cause blue smoke?

Yes, an overfilled engine oil may be what is causing the blue smoke. This can happen when the sump is overfilled and the crankcase is over-pressurized. As a result, the extra oil will then be pushed into the chamber and up the cylinder wall.

Can faulty injectors cause blue smoke?

Injector wear/leakage or air intake system obstructions may be the cause of blue smoke. Engine oil typically enters a combustion chamber and burns there, which then causes blue smoke. The most frequent causes of this are worn piston rings or low compression.

What does Blue Smoke mean?

When you see blue smoke from your exhaust pipe, it implies that oil has been combined with gasoline during the combustion process and is burnt up along with the remaining partially burned gasoline.

Conclusion – Blue Smoke from Exhaust

Whatever you do, handle blue exhaust smoke the same way you would an emergency. Any other issues with the car’s engine might be incredibly expensive to remedy. So, please make an effort to address the problem as soon as it is identified.

Use the oil recommended for your car by the manufacturer to ensure you’re doing everything possible to avoid this issue. When a top-up is needed, avoid adding too much oil.

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