What Causes Engine Exhaust Pipe to Spray Engine Oil?

[LeJeremiah]

Engine exhaust pipe spraying engine oil is usually caused by a damaged crankcase ventilation valve or severe wear between the valve stem and valve guide. Damaged Crankcase Ventilation Valve: For the safety of the crankcase, exhaust gases must be recirculated into the engine for re-combustion via the PCV system. If the PCV valve is damaged, the high-pressure exhaust gases in the crankcase have nowhere to go and can only spray out through the pipes. The simplest troubleshooting method is to directly pull out the oil dipstick and check if engine oil is spraying from the dipstick insertion tube. If so, it indicates a damaged PCV valve. You will need to visit a repair facility to replace the PVC valve. Severe Wear: Due to significant wear between the valve stem and valve guide, excessive clearance is created, leading to oil leakage. In this case, repair is not possible, and the only solution is to replace the valve stem and valve guide.

[SanPaige]

I've been driving for decades and have often encountered this issue. Engine breather tube spraying oil is usually caused by worn-out piston rings, which fail to seal properly, allowing oil to seep into the combustion chamber and then spray out through the tube. It could also be due to leaking valve stem seals or a clogged PCV system causing excessive crankcase pressure that forces oil out. Vehicle aging and poor maintenance, such as overfilling with oil or using low-quality oil, can worsen this problem. If not addressed promptly, oil consumption will increase, contaminating the exhaust tailpipe, and prolonged neglect may lead to engine overheating and damage. I recommend first checking the dipstick to ensure the oil level doesn't exceed the maximum mark, and then inspecting the breather tube for carbon buildup or blockages. For safety, it's best to take the car to a professional repair shop as soon as possible to replace faulty components and maintain regular oil changes.

[McEleanor]

As someone who recently bought a car, I'm quite concerned when encountering similar issues. Oil spraying from the engine breather pipe is mostly caused by internal sealing problems, such as worn or cracked valve stem seals allowing oil to leak in. It could also be due to a clogged PCV valve creating excessive crankcase pressure that forces oil out. Overfilling the oil or overloading the engine during driving can trigger this too. If left unrepaired, it not only wastes oil but may lead to more severe failures like engine smoke and stalling. What I've learned is: First, park the car in a safe place and check if the oil level is normal - don't randomly add additives. Then consult car-savvy friends or directly drive to a 4S shop for comprehensive inspection - spending small money prevents big disasters. Regular engine maintenance is crucial.

[Annabeth]

I often tinker with cars, and oil spraying from the exhaust pipe is a common issue. The root cause is usually damaged piston rings or valve stem oil seals, which fail to seal properly when worn, allowing oil to enter the combustion chamber and spray out. A clogged PCV system is also a frequent culprit, causing pressure imbalances that force oil out. Older cars are especially prone to this, with poor oil quality or neglected maintenance accelerating deterioration. For solutions, first check that oil levels aren't overfilled and clean the PCV valve; if that doesn't work, use professional tools to inspect internal components. Timely repairs can save fuel and prevent pollution, otherwise engine efficiency will drop rapidly. It's recommended to regularly check exhaust performance and change oil periodically to extend engine life.