See full version: What Happens When You Put Too Much Oil in Your Car
When too much oil is added, the level in the oil pan becomes too high. That allows a fast-moving lobed rod called the crankshaft to come into contact with the oil and essentially aerate it. The result is a foamy, frothy substance that cannot properly lubricate the engine. Think of this as your engine’s way of turning cream into whipped cream. No one wants whipped cream lubricating their engine. here
If you suspect you have too much oil in your engine, the quickest way to get an answer is to look at the dipstick. With the exception of some high-end exotic models, this simple part is found in all types of cars, typically has a bright yellow pull handle, and features low and high marks to show if your car has too much, too little, or the perfect amount of oil. It’s advisable to get into the habit of checking the level frequently, and always after an oil change. Consult your owner’s manual for specific guidance on checking your car’s dipstick. more
Engines are comprised of hundreds of precision-crafted parts working in unison at high speeds and temperatures, all of which require oil for proper lubrication and smooth movement. You, or your mechanic, add oil to an engine to the crankcase via the cap labeled “Oil” under the hood. The oil settles in the oil pan when the engine is not running. When you start the engine, the oil circulates throughout the engine and passes through an oil filter that removes contaminants that could potentially cause damage. more
Also of concern, the extra oil creates excessive pressure inside your engine that will look for an escape through various gaskets and seals. If one or more of those fail, that will lead to leaks and costly repairs. [links]
While the PCV Valve is intended to stop direct oil flow, we know from the use of PCV Catch Cans that some motor oil gets through in the best of circumstances. If the valve cover is full of oil as the OP describes, even more will get through. here
Since all oil pumps are designed to pump liquid rather than (compressible) gas, even though the pump is still operating, it's literally sucking air instead of pumping vital engine oil. The net effect is that the oil doesn't get delivered to the places it's supposed to go, so a gross excess of engine oil can kill your engine by the exact same cause as not having enough engine oil. more
If an engine is that full, it will pump oil through systems it shouldn't, such as the PCV system into the intake manifold. more
The real answer is- it depends. [links]
I know that having an excess amount of oil in the engine is a terrible idea, but I don't actually know why. It seems to me like the excess oil would eliminate at least some of the disadvantages to not having enough oil (like for example the parts would not rub and create friction because there would be plenty of lubrication). Due to this, I am guessing that having too much oil would have very different disadvantages to not having enough oil.
Sadly all new engines now use very low strength piston rings to cut down on friction between the cylinder walls and rings all to improve gas mileage and make it “greener”
They also use the thin as water 0W-20 oils for the same reason.
As a result the weak oil retainer rings fail to keep the thin oil from being sucked or blown past these weak rings resulting in oil burning engines not seen since the 1950s. [links]
I need a brand new engine for my toyota camry. Engine capacity is 2.4 and the model year is 2007. more
If you use the wrong type of oil in your engine, or your oil is simply old and has accumulated a lot of debris and dirt, then it will start to burn.
In most cases, synthetic oil lubricates engines better than conventional oils. But since synthetic oils are formulated differently, they have different flow properties. This means that synthetic oil is sometimes able to get through tighter openings than regular oil.
If you have seals or gaskets that are leaking oil, get them fixed asap. Usually it’s a fairly inexpensive process that will save you a lot of money in the long run.
If you have worn out or damaged piston rings, oil will be able to seep through them and then enter the internal combustion chamber. This will cause the oil to burn while carbon deposits form on the piston rings and cylinders.
Engine oil has a pretty tough job. It needs to be thin enough to allow the engine to start, yet thick enough to provide adequate protection at the engine’s operating temperature.
In most vehicles, the total amount of engine oil is between 4 and 8 liters. It depends on the engine volume though, so check the owner’s manual for your type of car. here
Maybe. How much was it overfilled by? What was the mechanic’s assessment? [links]