Either the 4.0 liter SOHC - V6 engine or the 4.6 liter SOHC - V8 engine
The 2003 Ford Explorer has single overhead cam (SOHC).
R134a
The 2003 Ford Explorer , 4.0 liter V6 engine uses ( 5W-30 ) With engine oil filter change it takes : ( 4.7 litres / 5.0 U.S. quarts of 5W-30 )
According to the 2003 Ford Explorer owners manual : ( DOT 3 brake fluid , meeting Ford specification ESA-M6C25-A )
It uses R-134a. There's a sticker under your hood in the engine compartment that tells you this and how much.
From 1991 to 1995 the only engine available in the Ford Explorer was the 4.0 liter OHV ( over head valve ) V6 - six cylinder engine
The 4.0 liter V6 engine takes ( 5W-30 ) The 4.6 liter V8 engine takes ( 5W-20 ) According to the Owner Guide
For a Ford Explorer : If you have the 4.0 liter V6 engine ( OHV and SOHC versions ) The recommended oil is 5W-30
In a 2003 Ford Explorer : Into the engine coolant reservoir ( located in the engine compartment , on the passenger side ) The thread on cap is your pressure cap / radiator cap Only add when the engine is cold ( up to the cold mark on the reservoir ) * It came from the factory with a 50 / 50 mix of distilled water and the correct type of antifreeze for the vehicle , Ford states to not exceed 60% antifreeze in the mix
For a 2001 Ford Explorer Sport : ( 5.0 U.S. quarts / 4.7 litres of 5W-30 engine oil , with engine oil filter change )
The 2000 Ford Explorer owners manual shows ( 5 W - 30 ) for all available engines
4.0 liter V6 engine ( 5W-30 ) 4.6 liter V8 engine ( 5W-20 ) According to the 2004 Ford Explorer Owner Guide