Ford 2003 Mustang Workshop Manual page 1610

System pressure is limited by an integral, internally-vented relief valve which directs the
bypassed oil back to the inlet side of the oil pump.
Oil pump displacement has been selected to provide adequate volume to ensure correct oil
pressure both at hot idle and maximum speed.
The relief valve calibration protects the system from excessive pressure during high viscosity
conditions.
The relief valve is designed to provide adequate connecting rod bearing lubrication under high-
temperature and high-speed conditions.
Cooling System
The engine cooling system includes the following:
radiator
coolant pump
the electric cooling fan motor and fan blade, activated by the variable control module
the degas bottle, which aids in maintaining the correct volume of engine coolant
thermostat
upper radiator hose
lower radiator hose
heater coolant hoses
Drive Belt System
The 4.6L (4V) DOHC engine is equipped with a serpentine drive belt. To ensure maximum life, a
replacement drive belt should be of the same type as originally installed.
The accessories mounted on the front of the engine are belt-driven by the crankshaft.
The serpentine drive belt is routed over each accessory pulley, driven by the crankshaft pulley
bolted to the crankshaft.
For service procedures, including tensioning, refer to Section 303-05 .