What Causes Oil Spray from the Exhaust Pipe of a Diesel Engine?
2 Answers
The reasons for oil spray from the exhaust pipe of a diesel engine are as follows: 1. It may be due to cylinder blow-by. 2. The crankcase breather is clogged or damaged. 3. The valve stem seal. Generally speaking, oil discharge from the exhaust pipe is caused by excessive crankcase pressure. 4. If the engine has just been serviced, residual oil in the cylinders may cause temporary oil discharge. 5. If oil leakage persists after prolonged operation post-repair, it is likely due to wear in the turbocharger's floating bearing seal ring. 6. Other complex reasons can also cause oil leakage from the exhaust tailpipe. Observing whether there is oil in the intake manifold or exhaust manifold can help identify the source and cause of the leakage.
I've seen diesel engines spraying oil from the exhaust pipe quite often, mainly due to worn or aged piston rings that allow engine oil to sneak into the combustion chamber and get expelled with the exhaust gases. Worn valve guides or failed seals can also let oil seep in. If the turbocharger's oil seal is broken, oil gets sucked into the exhaust pipe. A clogged crankcase ventilation system builds up excessive pressure, forcing oil into the exhaust pipe. Abnormalities in the fuel injection system, like stuck injectors, can cause this too, though it's less common. I remember a diesel pickup truck that was spraying oil – turned out to be piston ring issues, and replacing them completely fixed the problem. Early inspection and repair are key to prevent oil burning and engine damage, which can lead to costly repairs. Just pay attention to these components during routine maintenance.
