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What Every Driver Should Know About Blue Smoke From Exhaust Pipe

Blue Smoke From Exhaust Pipe

If you notice bluish gray or blue smoke from exhaust pipe it should be a cause for concern. It signifies your engine is burning oil as a result of an oil leak. This symptom might be caused by a leaky valve seal or a piston ring issue. What could be going wrong is that the engine seals aren't efficiently keeping oil out of the cylinders. 

Auto Repairs Are EXPENSIVE


This escaping oil might then combine with the fuel and burns. This reaction instantly results in the blue exhaust smoke you observe. This, among others, could be the reason and this is something you should pay attention to at the soonest possible time.


Whatever the reason is for a blue smoke from exhaust it signifies your automobile is inefficient, and the causes should be investigated as quickly as possible. In many of these cases, the oil is coming out owing to a faulty gasket, which if that is the case you still have some time. In this article we will talk about the issue in detail and what possibly you can do about it.

Top Reasons for Blue Smoke From Exhaust


  • Oil and fuel are combining.


As mentioned earlier blue smoke from exhaust could be caused by oil mixing with fuel and a symptom of bad piston rings and valve seals.


Your car's valve seals, piston rings, and PCV valves will not last forever. Furthermore, if you drive your car for 10,000 miles between oil changes, the oil becomes less effective in decreasing friction in your engine. This implies that the engine will create more heat, which will in turn warm and cool the gaskets, causing them to dry and break.


Because dry and damaged valve seals are ineffective at keeping fluids separate, your oil may mix with your gasoline, and the oil by-product may wind up being consumed in the combustion chamber. This implies that, instead of just gray smoke flowing out of the tailpipe on a regular day, you will now observe some blue smoke coming out of the exhaust system. 


If the blue smoke appears while you accelerate, it is typically caused by a piston ring problem. Sludge and carbon may collect into and around your piston rings, clogging them and preventing them from working correctly. If, on the other hand, blue smoke appears during deceleration, you are most likely dealing with a cylinder head valve guide problem.


Misfiring spark plugs and unpleasant vibrations while idling are further symptoms that your oil is seeping into your gasoline and burning, but blue smoke is an unequivocal, tell-tale symptom of this problem. If the piston rings are worn out, your engine must be replaced.


If you're lucky, the blue smoke from the exhaust can be caused by a clogged PCV valve, which can cause the engine to start sucking oil. Typically, replacing that valve with a new one is all that is required to resolve this issue. 


An engine that is devouring oil, on the other hand, may have major internal damage in the form of faulty piston rings, valve seals, or other important components deep inside the engine. Because replacing these components involves the disassembly of nearly the whole engine, it can be an expensive repair procedure.


But if this blue smoke appears solely after an oil change, you may have simply put in too much oil. The oil will froth up as a result, reducing its efficacy in dealing with lubrication and heat. Simply drain the extra oil and begin again.


  •  The Headers are dripping with oil.


As previously stated, oil can leak from the gasket between your engine block and head and drip onto your drivetrain's hot exhaust components. This will produce blue smoke, which will be highly odoriferous.


As you accelerate or idle, you may detect some blue smoke coming from the back of your automobile. A lot of times, if the head gasket is bad, the cylinder head needs to be replaced, and the only reason your head gasket needs to be replaced is when the head has gotten so hot that it warped. And because of that it now allows oil to seep through that gap.


  • Oil is dripping on hot engine components.


Another possibility is that your head gasket or valve cover gasket fails and your engine leaks a little oil. That oil will leak onto other heated portions of your engine compartment (such as your headers) before evaporating in a cloud of blue smoke.


This smoke will emerge from beneath your hood at idle, then from the back of your vehicle as you drive down the road. This is one another reason why you should constantly be aware of the odors emanating from your vehicle. 


  •  Bad Glow Plugs in Diesel Engines


Glow plugs and spark plugs are two completely separate types of vehicle components. Spark plugs assist a gasoline engine in producing the spark required to ignite the fuel and air combination inside the combustion chamber. 


Spark plugs are not used in diesel engines because they do not create enough heat for the mixture in the combustion chamber. Because a diesel engine has more severe cylinder compression, more heat must be created to ignite because compression heat alone is insufficient. A glow plug can supply the additional heat required to start a diesel engine.


If you detect black or blue smoke from exhaust of a diesel car or truck when you start it, your glow plugs are most likely faulty. This indicates that your vehicle will not start properly, and you may notice a longer than usual cranking time.


Connect a 12 volt test light to your positive battery terminal to see if the problem is caused by your glow plugs. Then, attach the wire to each of your light plugs one at a time to check whether you receive a reading.


Replacing them might cost anywhere from $100 to $500 depending on whether you do it yourself or have a respectable business do it for you, so it's worth checking to see if they're broken before forking over that much money.


  • Blown Turbo.


Another possible cause of blue smoke from exhaust is a blown turbo. Some owners of vehicles that are equipped with turbos have dealt with blue smoke that suddenly appeared in a big cloud as their vehicles blew a turbo. It can be caused by either a damaged turbo casing or by a turbo’s broken seal. Whatever has caused the blown turbo, it is sure that the culprit has let oil reach into the intake of the engine which caused the blue smoke from exhaust.  


  • Transmission Fluid Loss. 


Older vehicles equipped with vacuum controlled automatic transmissions have a modulator which is used to regulate the transmission shift. The said modulator is also subjected to problems and whenever it experiences any problem such as a failed diaphragm, it allows the engine to suck in transmission fluid. When this happens, it can lead to the transmission fluid being burned like the oil does which can set off blue smoke from exhaust.  


Blue Smoke From Exhaust: Is blue smoke from exhaust bad?


Blue smoke can look like a grayish smoke at first but when you look closely, you will notice a bluish color and it is an indication that the engine is burning a lot of oil. Blue smoke coming from the exhaust is not a good sign. Like mentioned earlier, it is an indication that your vehicle is suffering from worn engine components such as the piston rings, positive crankcase ventilation or PCV valves, or the valve seals. 


To fix this issue, your vehicle will have to be inspected to get the right diagnosis. Doing so will let you know if the problem is caused by the oil or by a damaged engine component. For vehicles that use petrol, the blue smoke from exhaust can be caused by oil leaking into the engine block while for vehicles that use diesel, blue smoke means that there is too much oil in the engine. 


Blue Smoke From Exhaust: How do you fix blue smoke from exhaust?


Now you have a better idea why your vehicle has blue smoke from exhaust, but how can you fix it? Here are some of the ways to fix a vehicle with blue smoke coming out from its exhaust.


  • Proper car care. 


Poor car maintenance such as not changing your car’s oil regularly can cause sludge to develop inside the engine. This causes the engine oil to enter in the combustion chamber which can lead to blue smoke from exhaust caused by a clogged cylinder head. 


To prevent this problem from happening, you need to practice proper car care by following the oil change interval set by your vehicle’s manufacturer. If it is too late for maintenance and the problem has already occurred, you will have to do some serious engine cleaning. 


The first thing you have to do is remove the valve cover and clean whatever you can to get rid of the dirt or debris buildups. Then you need to clean the oil drain back holes thoroughly and carefully. Make sure that you pay attention to how you disassemble them so you will know how to put it back. You can take pictures or record videos of you disassembling it to be sure.


  • Fixing the valve seal. 


If a worn out valve seal is the reason why there is blue smoke from exhaust, then it needs to be fixed or replaced. Replacing the valve seals involves a lot of process since the entire engine needs to be disassembled since the valve seals are tucked inside the valve spring. 


It will take a couple of hours depending on the make and model of your vehicle. The cylinder head will have to be removed, as well as the spark plugs, pushrods, and the rocker arms. There are times where the mechanic will dismantle, remove the cylinder head, and then use a cylinder kit that has a cylinder head gasket to replace it. 


However, there have been some known methods that make replacing the valve seals not too hard and it can be done at home. It is possible only if you know what you are doing. You can replace the valve seals without removing the head if you have the right tools and if you are confident enough to do it. 


If you want to do the replacement yourself, you have to make sure that you will not drop the valve into the engine. The difficulty of the replacement depends on whether the vehicle you have has an engine with an overhead camshaft or not. If it has, it might need more work and time since you will have to remove it to get to the valve stem.   


  • Replacing the bad glow plug and fixing the PCV valve.


If the blue smoke from exhaust is caused by a faulty glow plug, then replacing it with a new one can fix the issue. Replacing a bad glow plug can be done at home if you have the right tools. For a glow plug replacement, you will have to use a manual torque wrench and of course, you also need to get the right glow plug. 


When you have succeeded in replacing your bad glow plug with a new one, keep in mind that when you reach its tightening torque, you need to stop turning it. Doing so might break the bad glow plug. 


When it comes to fixing the PCV valve, it just involves a very simple process. You just need to find a tube that is connected to the intake manifold and follow it until you spot the PCV valve. You can then remove it and replace it with a new one. 


Blue smoke from exhaust can usually be noticed in the morning when you start the engine after parking overnight. If you notice it, it is best that you don’t drive your car until the problem is fixed.  You should have it checked by a mechanic immediately since worn internal components or oil mixing with fuel that causes blue smoke from exhaust is not supposed to happen. It can cause other serious problems to occur. 

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