Blue smoke from exhaust is not a good sign at all. Whenever a car’s exhaust starts emitting any other color of smoke different from thin white or something very light in the similitude of water vapor, it is a sign that there’s a problem.
This challenge is closely related to the car’s combustion system in the engine, and it can be detrimental if not rectified immediately.
Meanwhile, let’s check out what may be responsible for a car’s exhaust emitting blue smoke and the best possible way of fixing the issue before it gets further complicated.
What Does Blue Smoke From Exhaust Mean?
Blue smoke is a clear sign telling your car engine is burning oil. What happens is that the piston rings or the valve guide seals, or other components of the engine are worn or broken, causing oil to leak.
The oil will flow into the combustion chamber, then it is being burnt together with the fuel, creating blue smoke. It also creates an awkward smell and is not good for your health to breathe in.
What Causes Blue Smoke From Exhaust?
Below is a comprehensive list of all the reasons why your exhaust smoke might be blue.
#1. Worn engine oil seals.
Engine oil has to make its way around the engine, lubricating the correct components without entering places it shouldn’t be, like the combustion chamber. It is kept out of these places by seals that may become worn over time, allowing oil to leak through them.
Malfunctioning seals should be replaced immediately, but locating them isn’t always easy – it’s a job best left to professional mechanics.
#2. Blown head gasket.
When head gaskets fail, they are notorious for leaking oil, which can make its way into the exhaust system and other places it shouldn’t be, where it makes contact with hot surfaces and produces blue smoke.
#3. Worn pistons and piston rings.
Pistons convert the energy from combustion into a mechanical action, transferring it to the crankshaft. They depend on piston rings, which create an air-tight seal in the cylinders of the engine.
When either the pistons or rings become worn, oil may start leaking into the fuel, creating blue smoke when the mixture is burnt.
Replacing pistons is a challenging job that you shouldn’t undertake without the required expertise.
#4. Leaking inlet manifold.
The inlet manifold distributes air to the engine cylinders, ensuring enough is available when the valve opens during every intake stroke. If it starts to leak and allows oil in the cylinders, the oil will be burnt along with the fuel – by now, you know the result.
You can purchase inlet manifold sealants, providing a temporary fix for small leaks. However, sealant is not a long-term solution and is unsuitable for a significant leak.
#5. Damaged valve stem seals.
Valves control the amount of fuel and air allowed into the cylinders. They are fitted with high-strength rubber seals, which are pretty durable, but they can still become cracked due to high temperatures and general wear.
If faulty valve stem seals are the problem, a mechanic will often use specialized tools to compress the valve spring before making a replacement.
#6. Blown turbocharger.
This explanation applies specifically to cars fitted with a turbocharger. When this component blows.
You will likely notice a large cloud of blue smoke from the exhaust caused by a broken oil seal or damaged turbo casing inside the turbocharger, allowing oil to seep into the intake manifold.
#7. Faulty PCV valve.
PCV stands for positive crankcase ventilation. This type of valve is crucial in removing exhaust gas and unburnt fuel from the engine block.
Engine valves are notorious for getting stuck, especially as they age, and when this happens, it allows air, oil and other gases to mix within the engine, producing blue smoke.
Fortunately, PCV valves are affordable to replace.
#8. Defective glow plug.
This fault applies to diesel cars only; petrol engines have spark plugs. Read this guide for more information about the difference between spark and glow plugs.
A bad glow plug is probably to blame if you notice blue-white smoke from your exhaust when you start the car, which disappears after the engine has heated up.
Diagnosing Blue Smoke from Exhaust
To diagnose blue smoke, check the oil level and condition first. Low, dirty, or overfilled oil can cause or worsen the issue.
Next, inspect the PCV valve and hoses. A clogged or faulty valve can push oil into the intake, causing smoke. Remove the valve to check for sludge or blockage.
A compression test can indicate whether the piston rings or cylinders are worn. If one or more cylinders have low compression, it usually means oil is leaking past the rings.
Check valve seals by removing the valve cover. Oil around valves means leaking seals that need replacing.
Notice when the smoke appears. At startup, suspect valve seals. During acceleration, suspect piston rings or turbo. Constant smoke points to PCV issues or overfilled oil.
Follow these steps to identify the cause of blue smoke and decide if you can fix it or need a mechanic.
How To Get Rid Of Blue Smoke From Exhaust?
As blue smoke coming out of exhaust can be caused by some of the reasons mentioned above. So to get rid of blue smoke, you should find the cause and fix it as soon as possible.
Here are some effective methods to fix the problems of blue smoke from car.
#1. Clean the engine.
Poor maintenance can cause sludge accumulation inside the engine. As a direct result, oil reaches the combustion chamber and causes blue smoke, a direct result of clogged cylinder heads. The solution for this issue is however simple.
First of all, remove the valve cover and do the necessary cleaning to rid your engine of debris. Despite various types of engines, the first thing which can cause blue smoke is surely the engine.
Clean the drain back holes carefully and recheck and reassemble them. After the mending job, wait for 2 or 4 more days for the remaining oils to clean away.
#2. Fix valve seals.
Replacing valve seals is not too hard and can be done at home by someone who can work on engines comfortably. The big thing to bear in mind is to not drop the Valve into the engine.
So to keep the valve up, some people often use compressed air put in via the spark plug opening.
The work of changing the valve seals will be dependent on whether the engine has an overhead cam or not. If your engine has an overhead cam, it will require more work as we need to remove it to access the valve stem.
The objective is to remove springs from the valve and the rocker arm. The next things to do are to lift the old valve stem, seal the valve stem and replace it with the new one. You can use some special tools to compress the valve spring and remove it out of the way.
#3. Fix the bad glow plug.
If your car has a glow plug, the best thing you should do is replace it with a new one.
#4. Fix the PCV valve.
Fixing PCV Valve is simple and cheap as well. To do this, you need to look for a tube that links to the Intake Manifold. Keep following the tube back until you see your PCV Valve. Then take out the old PCV Valve and replace it.
#5. Fix blown turbo.
It is not a good idea if you drive a car with a blown turbo. This is because bits of metal will be created due to the lack of oil in the turbo. Then these bits of metal will come into the engine and damage the engine.
So before you fix the turbo, you should investigate what damage the bad turbo can cause. If the turbo did not break into small pieces, then you may be lucky. In this situation, you just need to rebuild it or replace it.
If it breaks into small pieces, you may need help from a mechanic as your engine is damaged.
#6. Fix transmission modulator.
To fix the transmission modulator you should locate its position, then remove it and replace it with a new one. You also need to replace the vacuum line if damaged by transmission fluid.
Is Blue Smoke from Exhaust Bad?
Short answer? Yes, blue smoke is bad news, even if your car seems to run “just fine” for now.
The presence of blue smoke means that your engine is leaking or burning oil, which can seriously hurt performance and reliability over time.
Here’s why it’s a big deal:
- Oil isn’t supposed to be in the combustion chamber. It’s meant to lubricate parts like pistons and valves, not get torched like gasoline.
- Burning oil means less lubrication, which leads to wear and tear. That adds up quickly, and you’re looking at possible engine rebuilds or total failure.
- Your car’s emissions go up, and it could even cause you to fail a vehicle inspection or emissions test in many states or countries.
Besides, it’s just embarrassing to drive a car that smokes like it’s got a nicotine habit. The longer you let it go, the worse (and more expensive) the problem gets.
You’ll find yourself topping up oil constantly, dealing with sluggish acceleration, and maybe even fouling your spark plugs or catalytic converter.
So if you’re seeing blue smoke, don’t treat it as a minor cosmetic problem, it’s a red flag that something inside the engine needs attention.
How much does it cost to fix blue smoke from exhaust?
Once you notice that your car’s exhaust produces blue smoke, it would be best to fix it immediately. The cost of fixing the problem is not very expensive compared to replacing a car’s engine. So, it would be better to rectify the issue than risk complete engine damage.
The estimated cost will be around $80 for the part and somewhere around $300 for labor. However, this is just an estimated cost. Depending on your location, the car parts dealer, and the mechanic fixing the problem, it could be a little less or more.
Preventative Tips to Avoid Future Blue Smoke Issues
Using preventative measures can help avoid blue exhaust smoke and keep vehicles in top condition. Here are Wynn’s professional tips for long-term maintenance:
- Regular Oil Changes: Frequent oil changes prevent sludge build-up and keep the engine running smoothly. Always use the right grade of oil for each specific engine.
- Check the PCV Valve: Inspect the PCV valve periodically to ensure it’s working correctly. Replace it if it’s clogged or faulty, as it plays a critical role in managing oil flow.
- Turbo Maintenance: For turbocharged vehicles, use Wynn’s Turbo Cleaner regularly to prevent deposit build-up and ensure proper operation.
FAQs.
Q: Is blue smoke from exhaust bad?
Of course, blue smoke produced from a car’s exhaust is a bad occurrence; hence, it must be fixed as soon as possible to avoid complications. In some cases with petrol cars, that symptom may be due to oil leakage into the engine block where the fuel mixes with the air.
Meanwhile, when blue smoke is released from the exhaust in vehicles with a diesel-powered engine, it is usually due to excess oil in the car’s engine.
It isn’t a pleasant experience, especially with the horrible smell from the smoke. This is also not a good sign, and it should be fixed as soon as it is seen to avoid further damage to the car’s engine.
Q: Does blue smoke mean blown head gasket?
A blown head gasket will always be exposed by blue smoke coming from a car’s exhaust. This is usually due to oil leakage from the vehicle’s gasket.
In some other cases, white smoke may be seen coming from a car’s exhaust. When a car’s exhaust produces white smoke, it is usually due to burning coolant leaking into its cylinder.
If you experience blue smoke from exhaust on cold start or at any other time, endeavor to consult a professional auto mechanic to check out the problem and get it fixed as soon as possible to avoid further damage.
Q: Can low oil cause blue smoke?
Low oil may not necessarily cause blue smoke to be produced from a car’s exhaust. However, when blue smoke consistently comes out from a vehicle’s exhaust, it is a sign of oil leakage into the vehicle’s engine block, and this may result in a low oil level.
So, if your car’s engine oil is low, try to get a refill as soon as possible. Meanwhile, if the vehicle constantly produces blue smoke from the exhaust, your car may continually experience an oil shortage. So, endeavor to fix any issue that may result in further complications.
Q: What color should exhaust smoke be?
A vehicle’s exhaust smoke is expected to be thin white or very light. The smoke is usually similar to water vapor. The experience is common during cold seasons, especially when you start the car for the first time, probably in the morning.
Any color of smoke other than the specified above may be due to one or more faults within the engine compartment.
If you ever experience a change in your car’s exhaust smoke, endeavor to contact an expert auto mechanic to figure out what the problem is and to fix it as soon as possible.
Q: Can a bad EGR valve cause blue smoke?
Yes, a bad exhaust gas recirculation (EGR) valve can cause blue smoke to be produced from a car’s exhaust. Sometimes the EGR system may be clogged up, and at other times, it may stick open, thereby allowing spent gases from the exhaust to enter the combustion system.
When the spent gases get into the combustion system, it alters the combustion process and produces blue smoke from the car’s exhaust. It can also lead to rough idling and engine management light (EML) warning display.
Q: Can a bad O2 sensor cause blue smoke?
The O2 sensor is responsible for detecting the level of oxygen in a vehicle’s exhaust gases, thereby sending a signal to the vehicle’s engine management computer.
Once the signal is sent, the computer directs the carburetor or the fuel injection system to alter the amount of fuel released into the vehicle’s intake system. Under normal working conditions, the vehicle’s exhaust cannot produce blue smoke.
Meanwhile, when the O2 sensor is bad, the fault may either make the vehicle run lean or rich. If the car runs extremely rich, it damages the engine and causes the exhaust to produce black smoke. On the other hand, if it runs extremely lean, it causes the exhaust to produce blue smoke.
Q: Does synthetic oil burn blue smoke?
It is obvious that the reason why a car’s exhaust may produce blue smoke is due to the burning of leaking oil in the car’s engine block. Using synthetic oil seems to be the solution to the constant outflow of such blue smoke from the car’s exhaust.
If you constantly experience your car’s exhaust producing blue smoke, it may be time to switch to synthetic oil to stop the smoke. You may have to check out a dealer with quality synthetic oil for this purpose.
Final Words
No matter what you do, treat blue smoke from exhaust like you would treat any other emergency. Any further complication within the vehicle’s engine may be very costly to fix. So, endeavor to fix the issue as soon as it is discovered.
Meanwhile, ensure to do all that you can to avoid this situation by using the recommended oil for your vehicle based on the manufacturer’s recommendation. Also, ensure to avoid filling excessive oil whenever you need to top it off.