At the right level, new engine oil effectively protects against excessive friction during cold starts while providing more fuel during hot periods. Any gas or diesel engine can depend on the amount of oil installed, and pouring too much into the crankcase will cause the oil to foam or thicken, making it difficult for the oil to flow in hot or cold conditions.
If the oil can’t flow, it can’t get through the small oil passages to lubricate the valve, combustion chamber, pistons, and other internals. It’s no different than churning milk and turning it into butter, and the consistency of butter isn’t what the engine needs to keep it from breaking down.
In addition, too much oil means unnecessary oil loading, which leads to leaking gaskets and oil seals. If your car suddenly has a check engine light after an oil change and has symptoms such as blue or white smoke, subpar performance, or unusual engine noise, it may mean that the engine is drowning in oil.