Engines tend to burn oil, some more than others. Some leak oil, some more than others. So if you don't check it and top it up, it might run short.
The engine Burn out
Good quality oil, no short runs, always get the engine up to temperature, regular oil and filter changes, regular engine flushes.
Because of Frictional Force
It literally means the oil that keeps the car's engine cool is running hotter than normal.
check oil for water and radiator for oil, if engine oil has water miced with it ,the oil will be milky looking same does for radiator
oil, gas, engine, brakes, tires, battery
what is a good engine oil to use in my car
It could be that it was overfilled, or it could be that there is a crack in the head gasket that is allowing coolant to enter the oil pan. Or it could simply be condensation in the engine which usually occurs if the car does too many short journeys.
It depends on which engine you have. If it is for a car, look in the owners manual if available. Short of that, at least post in the question the make, model, and year of the car.
It will run but not for very long. No oil pump means no oil will be moving throughout the engine to lubricate and cool the engine. The engine will overheat, bearings & rings will wear and in a short amount of time the engine will lock up and self destruct.
An oil leak is always going to be out of the engine as the engine contains oil and the car does not. I think you are saying you are loosing oil with no apparent leak. If that is the case the engine is burning oil and that is why you see no leaks.
88 fleetwood has a very tough engine i use any oil i can aford . my car runs good with any type of oil