Possible Reasons Smoke is Coming From Your Car’s Tailpipe
When smoke billows from your vehicle’s tailpipe, it typically means your engine is burning oil. I’m referring to the large, dark plumes as opposed to the small white wisps caused by condensation. The problem is that the root cause of the oil burn can potentially be located in several places. It may be due to a failing valve seal, pressurized oil pan, jammed PCV, or deteriorating piston rings.
Below, we’ll take a brief look at each of these factors. I’ll explain how they contribute to an oil burn and result in smoke coming from your automobile’s tailpipe.
Your Valve Seals Are Failing
Your engine’s cylinder head is located directly above the combustion chamber. A number of valves are contained within the cylinder head. Under normal conditions, each valve has a seal which prevents oil from dripping into the combustion chamber. If the seals deteriorate, they’ll fail to do their job properly. As a result, oil enters the chamber and the 4-stroke combustion process burns it.
Your PCV Is Jammed Or Clogged
As your engine goes through its internal combustion process, pressure builds within it. The PCV allows this pressure to dissipate. However, over time, it can become clogged with carbon, a side effect of the combustion process. When this happens, it can lead to excess pressurization of the crankcase. The result? Oil ends up being directed into the engine where it burns, producing smoke from your tailpipe.
Your Piston Rings Are Worn
Each of your pistons has a ring around it that functions as a seal. One of their jobs is to prevent energy from escaping the combustion chamber during the 4-stroke process. They also lubricate the walls of the cylinder. Like most parts, the rings can deteriorate over time. When they do, the pressure created during combustion is directed to the crankcase. Remember what happened in the case of the PCV clog causing excess pressurization in that part? The same thing occurs – oil makes its way into the engine.
What Does Blue Exhaust Mean?
The color of exhaust confuses a lot of motorists. Sometimes, it’s white while in other cases, it’s dark gray or blue. First, if the exhaust is white (and assuming it is not caused by normal condensation), it might imply a leak in your car’s head gasket. If the gasket leaks, water can gain access to the combustion chamber. If the exhaust is dark gray, it may suggest that your master cylinder is failing.
Blue smoke implies that oil is being burned within the combustion chamber. And that is caused by broken valve seals, a jammed PCV, or deteriorating piston rings.
Here’s the takeaway: if you notice smoke coming from your vehicle’s tailpipe, have a mechanic take a look. Something has failed or deteriorated and it will not get better on its own. If you wait to have it repaired, you risk exposing your car to even bigger problems down the road.