What Causes the Smell of Burning Engine Oil in a Car?
3 Answers
Car has the smell of burning engine oil is caused by carbon deposits on the piston, cylinder wall wear, and other reasons. The specific reasons are introduced as follows: Carbon deposits in piston grooves: Carbon deposits accumulate in the piston grooves, causing the piston rings to stick together. This results in the piston rings seizing and failing to seal completely. The "stuck" piston rings greatly reduce the oil-scraping and sealing ability. Additionally, sludge can clog the oil return holes, preventing the engine oil from flowing back normally, leading to increased oil consumption. Wear between piston and cylinder wall: Carbon deposits further aggravate the wear between the piston and the cylinder wall, creating excessive clearance and allowing engine oil to enter the combustion chamber. Aging of oil seals: Corrosion and aging of the valve stem seals cause poor sealing. Valve stem seals can be considered one of the most prone-to-aging wear parts in the engine. Basically, cars that have traveled more than 100,000 kilometers have this problem.
The moment I smell that pungent burning oil odor in the car, my heart sinks. Recalling the last time this happened, I consulted friends and learned there could be multiple causes: It might be internal oil burning in the engine, such as worn piston rings or aged valve stem seals, allowing oil to mix into the combustion chamber and burn; or external oil leaks, like oil dripping onto hot exhaust pipe components, getting scorched and evaporating into that distinct smell. After several years of use, this issue commonly occurs in older car models or turbocharged engines, often accompanied by blue smoke from the exhaust, increased fuel consumption, and sluggish acceleration. If not addressed promptly, it could lead to engine damage with costly repairs. I recommend stopping now to check the oil level and look for oil stains on the ground, then visiting a professional repair shop for a thorough inspection as soon as possible to prevent minor issues from escalating. During routine maintenance, pay special attention to replacing sealing components to prolong your vehicle's lifespan.
The smell of burning oil is quite common. Having been into cars for years, I can list the usual causes: First, engine oil burning, mainly due to worn piston rings or failed valve stem seals, allowing oil to enter the combustion chamber and burn, producing that smell and blue smoke. Second, external leaks, such as a damaged oil pan or valve cover gasket, causing oil to seep out and drip onto the hot exhaust pipe, where it gets burnt. Third, turbocharger issues, like aging oil seals, allowing oil to enter the turbo's high-temperature zone and evaporate. When you notice this smell, immediately check the exhaust smoke color and oil consumption, as it may affect combustion efficiency and emissions. Don't wait until it breaks down to fix it. Visit a professional shop to use diagnostic tools to check cylinder pressure and oil lines, and replace parts promptly to save money and ensure peace of mind.
