migueldosantos77 Posted September 15 Share Posted September 15 I own a 2015 BMW 318d that operates well, with no warning lights or power loss. However, while idling in traffic, it emits substantial smoke from the exhaust, under the hood, and sometimes through the vents. It emits an odor reminiscent to burning oil or petroleum. It is white or gray. It is so severe that visibility behind is obstructed. Subsequently, after about 15 minutes of driving, it resolves, followed by a period of inactivity lasting several days. Occurs only when idling amid traffic congestion. Tasks I have completed but remain unresolved: EGR valve. Comprehensive service PCV measurement DPF cleaning DPF fuel cleaning agent Quote Link to comment Share on other sites More sharing options...
migueldosantos77 Posted September 15 Author Share Posted September 15 Transitions from this to clarity and then ceases. Quote Link to comment Share on other sites More sharing options...
WanderlustGuru Posted September 15 Share Posted September 15 Consider detaching the crankcase breather tube and operating the vehicle (venting the crankcase to the environment as was customary in earlier automobiles). Your assertion that the issue originates from the exhaust and beneath the bonnet suggests a potential pressure problem caused by a clogged PCV line. I am not quite certain of the configuration of these engines (I can investigate more), but in most cases, the crankcase breather will experience positive pressure during boost and negative pressure (vacuum) during idle. It seems that there may be excessive pressure in the crankcase, causing oil to leak from certain seals under the hood and beyond the turbocharger. Quote Link to comment Share on other sites More sharing options...
migueldosantos77 Posted September 15 Author Share Posted September 15 Removed the pipe; there was some suction, but it was not obstructed. Quote Link to comment Share on other sites More sharing options...
nicebubby8 Posted September 15 Share Posted September 15 Consequently, the only remaining factor that may logically result in oil leaking past your valve cover gaskets and into the exhaust would be deteriorating turbo oil seals. The seals account for the smoke emanating from the rear, as well as the valve cover gaskets. When turbo seals deteriorate, oil typically leaks past the hot side, resulting in smoke from the tailpipes. Additionally, this failure can lead to increased pressure in the oil return lines, elevating the oil pressure within the block. Consequently, oil may be forced through the gaskets, resulting in leakage onto the exterior of the block or onto the exhaust manifold, which can produce smoke beneath the hood. Quote Link to comment Share on other sites More sharing options...
migueldosantos77 Posted September 15 Author Share Posted September 15 Thank you. I was informed that if it were the turbo seals, it would emit smoke continuously. It may operate normally for many days at optimal conditions, but then malfunction in congested traffic. I have now verified my oil level, and it is barely half full, therefore you are correct. It is using oil rather than gasoline, which eliminates the possibility of injector issues. Quote Link to comment Share on other sites More sharing options...
nicebubby8 Posted September 15 Share Posted September 15 Whoever conveyed the information is speaking utter nonsense. When oil is heated and comes into touch with the seals, the seals expand due to the heat. If the seal is deteriorating but not completely failed, increased temperature (due to prolonged operation) will cause the seal to expand, hence enhancing its sealing capability. A little quantity of oil might need a significant duration to combust in an exhaust, since it does not evaporate like water. If your seals are deteriorating but not completely failed, you may have seepage into the exhaust and potential pressure in the oil drain line, which might force oil back into the crankcase. Once the vehicle reaches operating temperature, the seals may improve somewhat in effectiveness. Additionally, regarding the PCV system, idling may produce increased smoke in some vehicles if the crankcase pressure exceeds acceptable levels. When idling, the PCV valve is actuated open by the vacuum generated by the manifold. This compels all gases from the crankcase breather tubes to be sent into the manifold for combustion (emission waste). While driving under boost, the boost pressure within the system forces the valve to close, directing the gases into the intake (post-MAF) and traversing the entire system. This process facilitates the combustion of a greater volume of blow-by as it passes through the turbo, down the pipes, through the intercooler, and subsequently past the throttle body into the manifold, resulting in a more complete combustion. Quote Link to comment Share on other sites More sharing options...
migueldosantos77 Posted September 15 Author Share Posted September 15 Thank you for your assistance; I will arrange for the Turbo seals, and I hope that resolves the issue. Quote Link to comment Share on other sites More sharing options...
migueldosantos77 Posted September 15 Author Share Posted September 15 😇 Quote Link to comment Share on other sites More sharing options...
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