Exactly what is recommended by the manufacture as listed in your owners manual.
100% Synthetic would be a good choice.
No oil filter, no oil, lots of damage.
Yes.
It is recommended that oil be changed every 3,000 miles or 6 months (whichever comes first) for regular oil and 7,500 or 12 months for synthetic oil
A good gear driven oil pump is the best one for the system.
Probably not for long. If the engine is deprived of oil, it will seize up and stop running. What kind of car is it and how do you know it has a weak oil pump?
One reason why oil will drain out of a car after filling it up could be a hole in an oil filter. The car will need to be fixed before being driven.
Basically it's inside the oil pan at the front of the car, by the crankshaft sprocket. It is driven by the crankshaft.
A car can be driven with a cracked head, but not very far. Once the head is cracked, the engine will start mixing oil and water and it is likely that the motor will lock up.
yes do to rot on engine seals they need oil...
Drive it to the mechanic. You have something wrong and that is what the car is telling you. Oil, water, something is not right.
You should change your oil every 3 months or 3,000 miles.