What Causes Engine Oil Leakage?
3 Answers
Engine oil leakage can be caused by the following reasons: 1. Improper engine assembly, insufficient surface cleaning, damaged or displaced sealing gaskets leading to oil leakage. 2. Incorrect installation of sealing components without following specified procedures, resulting in insufficient or excessive tightening of nuts and bolts, causing loosening or breakage. 3. Overfilling of lubricating oil or using incorrect oil grade, leading to abnormal internal oil pressure. 4. Product quality issues, where manufacturing defects cause porosity in engine components. 5. Prolonged engine use causing aging and failure of sealing components.
Last time I saw oil stains under my car's engine and got really scared. After checking, I found that engine oil leakage is quite common. It's mainly due to the aging and hardening of rubber seals on the engine, like the valve cover gasket and crankshaft oil seal, which become brittle and crack under long-term high-temperature operation. It could also be caused by loose oil pan screws or improperly installed seals—improper handling during oil changes can lead to leaks. The oil pipe joints in turbocharged cars are also prone to leakage. The worst-case scenario is if the engine has been damaged, with cracks in the cylinder block—that would be a big problem. Minor leaks can usually be monitored by checking the oil dipstick regularly, but if oil is visibly dripping, it's crucial to get it fixed immediately. The engine won't last if all the oil leaks out.
Old-timers all know that cars over five or six years old tend to develop minor oil leaks. Those rubber seals in the engine just can't withstand years of high-temperature punishment—they're bound to warp and crack eventually. The most common spots are around the valve cover edges, leaving coffee-stain-like oil marks. If the drain plug isn't tightened properly or its washer fails, you'll see drips under the chassis. The crankshaft front/rear seals are the worst offenders, often requiring engine removal for repair. Minor seepage isn't panic-worthy—just monitor oil levels regularly and keep it above the minimum mark. Replacing gaskets is relatively inexpensive, but never ignore leaks until the oil runs dry, or you'll face catastrophic engine seizure that could bankrupt you.
