Use a good synthetic oil, available at Wal*Mart or Auto Zone.
According to the 2003 Ford Focus Owner Guide ( North America ) ( 5W-20 )
A Ford Focus needs anywhere from 4.5 to 6 quarts of motor oil. The Ford Focus was fist produced in 1998.
4 quarts 10W40
A four cylinder 2009 Ford Focus hold 4.5 quarts of oil.
According to the 2008 Ford Focus Owner Guide : With engine oil filter change : The 2.0 litre four cylinder engines take ( 4.5 U.S. quarts )
According to the 2007 Ford Focus Owner Guide : For the 2.0 and 2.3 liter four cylinder gasoline engines : ( 5W-20 )
According to the 2006 Ford Focus Owner Guide : For the 2.0 and 2.3 liter four cylinder engines : With engine oil filter change : ( 4.5 U.S. quarts / 4.3 litres of engine oil )
According to the 2002 Ford Focus Owner Guide : ( 5W-20 ) engine oil is recommended
In the oil pan, in the engine.
if it is a new ford focus then no, alot of new cars have regulators on them.
diesel
No