What Causes Engine Oil to Leak Out?
2 Answers
Engine oil leaking out is caused by the aging of the four supporting components, cylinder liner, piston, piston rings, and turbocharger. Reasons for the aging of the four supporting components: Failure of the "three filters" allows dust and impurities to enter the cylinder, causing abrasive wear. After replacing the four supporting components, the engine was not properly run-in according to the technical requirements, leading to excessive carbon deposits when the engine does not burn fuel completely. These deposits fall off and cause abrasive wear. Reasons for the aging of piston rings: Light leakage in piston rings, insufficient elasticity of the rings, reverse taper in rings with outer taper due to production issues, poor thermal stability of the rings, and significant loss of elasticity.
I've encountered the issue of engine oil leaking out several times, and there are two most common causes. First, aging or cracked seals or gaskets, such as the valve cover gasket or oil pan gasket, shrink and crack under prolonged high temperatures, causing oil to seep out. Second, excessive crankcase pressure—when the PCV valve fails, internal pressure rises too quickly, forcing oil out. Another possibility is overfilling the oil; if too much is added, it can overflow due to thermal expansion. I recommend you stop the car immediately and check for oil stains on the ground, then feel the hood temperature to see if it's abnormal. If too much oil leaks, it could pollute the environment at best or cause engine overheating or even fire at worst—definitely not worth the risk. Quickly find a reliable repair shop to replace the worn-out parts before it escalates into a major overhaul. During regular maintenance, pay attention to the oil level and keep it around the middle of the dipstick marks.
