What Locations Should Be Checked for Car Oil Leaks?
3 Answers
"Car oil leaks should be checked at the oil filter, engine oil pan, valve cover gasket, and shock absorbers. Oil filter leak: The oil filter, also known as the oil cleaner, is primarily responsible for filtering impurities, gums, and moisture from the oil, delivering clean oil to various lubrication points. During engine operation, metal wear particles, airborne contaminants, and oil oxidation byproducts gradually increase the impurities in the oil. If unfiltered oil enters the lubrication circuit directly, it can carry these impurities into the friction surfaces of moving parts, accelerating wear and reducing engine lifespan. The main causes of oil filter leaks are improper tightening, damaged sealing rings, or a broken oil filter. Poor-quality oil filters can also be a contributing factor. Solution: Replace the oil filter or the filter base. Engine oil pan leak: This location tends to leak more frequently than others. The leak is usually caused by a loose or damaged oil drain plug, which can be resolved by using a screw washer and replacing it regularly according to the maintenance schedule. Other possible causes include undercarriage impacts or oil corrosion leading to poor sealing. Solution: Replace the oil pan. Valve cover gasket leak: While the oil pan is sealed with adhesive, the valve cover relies on a gasket for sealing. This area is also the most prone to leaks. Severe leaks can result in excessive oil on the engine and transmission, requiring cleaning with an engine degreaser. Solution: Replace the valve cover gasket and reapply sealant. Shock absorber leak: Shock absorbers are wear-prone components and often develop leaks after tens of thousands of kilometers. Many car owners encounter this issue. Note that some oil seepage is normal during operation, so it's essential to confirm whether it's an actual leak. If a leak is detected, first tighten the oil cylinder cap nut. If the leak persists, the oil seal or gasket may be damaged and require replacement. If the leak continues, inspect the shock absorber rod for stiffness or uneven movement, and check for excessive clearance between the piston and cylinder, bent piston rods, or scratches on the piston rod or cylinder surface."
I habitually crouched down to inspect the most common trouble spots when I found oil leaking under the car. Starting with the oil pan—a large metal plate—it’s a frequent leak point due to gasket aging or loose bolts; a sticky feel is a bad sign. The oil filter is the next target—drips occur if it’s not tightened properly or the seal cracks. The transmission bottom is also prone to rust and gear oil seepage. The oil pump connections and fuel line fittings need careful checks—any looseness means leaks. After parking, sprinkle some flour on the oil stains to trace the source by their shape the next day. Don’t ignore minor leaks—delaying repairs leads to costly overhauls. Regular maintenance, like replacing gaskets, ensures peace of mind and safe driving shouldn’t be overlooked.
When I first started driving, I was really panicked because my car was leaking oil. Peeking under the engine, the gray-black oil pan had oil stains, revealing that the cylindrical oil filter wasn't properly aligned and was also leaking. The crankshaft rear oil seal is tucked away inside and requires a strong flashlight to inspect. Loose oil pipe line connections can also be troublesome. If there are stains under the transmission, it might be a gear oil issue. It's best to park on a level surface and let it sit overnight to check for oil drip marks. Don't make the same mistake I did by delaying repairs for days, which ended up costing me 3,000 yuan. Regular inspections and developing good habits are essential.
