What Causes Engine Oil Leakage in a Car?
3 Answers
Engine oil leakage in a car is primarily caused by the failure of rubber seals in the engine. Below is an introduction to the functions of engine oil: 1. Lubrication to reduce wear - The relative sliding between the engine's pistons and cylinders, as well as between the crankshaft and bearings, causes wear. Engine oil forms a thick oil film between these sliding surfaces, separating the moving parts to minimize wear. 2. Cooling - Engine oil carries heat back to the oil pan, where it is dissipated into the air, assisting the radiator in cooling the engine. 3. Cleaning - Engine oil circulates carbon deposits, sludge, and metal wear particles from engine components back to the oil pan, flushing away contaminants through the flow of the lubricant. 4. Shock absorption - When cylinder pressure rises sharply, it suddenly increases the load on pistons, piston rings, connecting rods, and crankshaft bearings. The lubricated transmission of this load through the bearings helps cushion the impact.
Last week my car had the same issue, spent hours troubleshooting only to find there are actually many causes of oil leaks. The most common is the oil pan gasket hardening with age - rubber materials become brittle and crack over time, especially in cars driven for 7-8 years. Another frequent culprit is the drain plug not being tightened properly or having stripped threads, often happening when mechanics do sloppy oil change jobs. If the oil filter gets installed crooked or its sealing ring deforms, that can cause seepage too. Places like the crankshaft front seal endure constant high temperature and pressure, causing rubber to degrade until it starts dripping. Never ignore oil leaks - first check for stains under your parking spot and inspect the dipstick level. If it's below minimum, don't drive - call a tow truck immediately. From my experience, take it to a reputable shop for lift inspection. Replacing gaskets costs peanuts compared to engine repairs.
I just dealt with the oil leakage issue on my vintage car last year. It mainly comes down to component wear or operational problems: like the valve cover gasket losing elasticity over time, especially in cars frequently driven short distances where oil tends to accumulate; then, if the oil filter is installed off-center during an oil change, it can leak—I learned this the hard way when I tried doing it myself once; also, aggressive driving can cause the oil pan to scrape and deform, and hitting hard objects under the chassis is the most common cause of this; not to mention high-pressure car washing damaging the seals. Remember, oil leakage is no small matter—low oil levels can harm the engine. If you notice oil drip marks after parking, first clean the bottom of the engine, drive for a couple of days, and then check the leak location again. Minor issues can be fixed by tightening screws yourself, but a damaged oil seal requires professional attention.
