Its a design problem. Ideally there shouldn't be.
Yes, but they make it into gasoline first. Crude oil is not the oil you put in the crankcase. That is oil that is refined from crude oil and then additives are added.
crankcase oil is the oil in the engine .some call it crankcase oil some call it engine oil
Worn piston rings. Incorrect weight engine oil. Gasoline mixed with engine oil. Crankcase overfilled with engine oil.
Yes. The oil drips into the crankcase via the oil filler location.
Not knowing what vehicle and engine you have you may have a faulty fuel pump leaking gasoline into the engine crankcase.
Crankcase oil is engine oil , so yes
Yes. Any internal combustions needs oil for lubrication. 4 cycle engines have a provision for oil storage in a crankcase. 2 cycle engines require you mix 2 cycle oil with the gasoline.
No, oil is oil and gasoline is gasoline, although gasoline is refined from crude oil.
The only way gas would be able to get into the crankcase is when the engine is off, gas is leaking down thru the carb's and passing thru the rings into the oil. Does the engine run well ? Is there always gas in the oil, or did you have trouble starting the engine and flooded it. If it was flooded once, that would do it. Change oil and filter.
If you do not use oil in the engine it will destroy itself due to lack of lubrication. If it is a 2 cycle you mix 2 cycle oil with the gasoline to lubricate the engine. If it is a 4 cycle then you put the oil in the crankcase to lubricate the engine.
The crankcase is the inner part of the engine block and oil pan.
If I spaced your words out correctly you are asking "What is the difference between 30 weight and 2-stroke oil?". All oil unless synthetic comes from crude oil. Crude oil is then refined into many things we use today such as different fuels, lighter lubricating oils, and heavier oils like grease. As far as the differences go between the 2 you asked about. They are both designed to lubricate internal combustion engines. Just because they lubricate these engines, they lubricate 2 wildly different types of engines. A two stroke engine has no crankcase oil to lubricate its internal components. 2-Stroke oil is designed to "mix" easily with gasoline to act as a carrier. The oil is "diluted" into the gasoline and sent into the engine via the carburetor. From there into the lower portion of the crankcase and gets splashed around in the crankcase and leaving some of the oil behind on the rotating parts. It then can lubricate any rotating parts. Some of it inherently goes to the combustion chamber and gets burned with the gasoline. In a 4 stroke engine where the 30 weight oil would be used has a "sealed" crankcase that holds the oil for lubrication. It is thicker and has a higher viscosity because it is not designed to be diluted.