What are the effects of excessive engine oil on the engine?
3 Answers
Excessive engine oil can have the following effects on the engine: 1. Increased oil consumption; 2. Reduced engine power; 3. Accelerated carbon deposit formation, damaging certain engine components; 4. Potential oil leakage from the crankshaft oil seal and shortened oil service life. Methods to address overfilled engine oil include: 1. Draining excess oil by removing the oil drain plug; 2. Using an oil pump to extract the excess. The primary functions of engine oil are: 1. To separate and lubricate moving parts, reducing component wear; 2. To carry heat back to the oil pan for dissipation into the air, assisting the radiator in cooling the engine; 3. To circulate and remove carbon deposits, sludge, and metal particles from engine components back to the oil pan, keeping the working surfaces clean.
I had a previous car that experienced overfilled engine oil, and I could clearly feel the engine sound becoming muffled, especially struggling during acceleration. Later, the mechanic explained that too much oil increases resistance when the crankshaft churns the oil, just like a person walking in deep water—it’s extremely strenuous. Additionally, the excess oil gets forced into the combustion chamber and burns, causing blue smoke from the exhaust pipe and generating a lot of carbon deposits. Over time, this can damage the catalytic converter. The most troublesome part was the excessive oil pan pressure, which the oil seals couldn’t handle—my car’s oil pan gasket started leaking, and the repair was a real hassle. So now, whenever I change the oil, I always check the dipstick to ensure it stays at the middle mark.
Adding too much engine oil is definitely not advisable, and I've learned this the hard way. Last time during maintenance, the mechanic accidentally overfilled my car with oil. At first, I noticed the throttle response became sluggish, and fuel consumption inexplicably increased. After some research, I discovered that excessive oil causes the crankshaft to whip up too much foam during rotation. These air bubbles entering the lubrication system can compromise oil film formation, leaving critical components inadequately lubricated. Moreover, the engine's operating resistance increases, naturally affecting power output. What's more concerning is that excess oil entering the combustion chamber can form stubborn carbon deposits, potentially coating spark plugs and even causing blue smoke from the exhaust pipe. Now I always personally verify the dipstick level during every oil change.
