2003 GMC Yukon Owner's Manual - Page 375

The engine oil fill cap for the VORTEC™ 4800, 5300, 6000 and 8100 V8 engine is located on the engine valve cover, on the passenger's side of the vehicle. All Other Engines When to Add Engine Oil If the oil is at or below the cross-hatched area at the tip of the dipstick, then you'll need to add at least one quart of oil. But you must use the right kind. This part explains what kind of oil to use. For engine oil crankcase capacity, see Capacities and Specifications on page 5-106. Your vehicle may have a cap with text and a graphic, or just a graphic as shown. See Engine Compartment Overview on page 5-12 for more information on location. Be sure to fill it enough to put the level somewhere in the proper operating range. Push the dipstick all the way back in when you're through. Notice: Don't add too much oil. If your engine has so much oil that the oil level gets above the cross-hatched area that shows the proper operating range, your engine could be damaged. 5-17