2003 Chevrolet Tahoe Owner's Manual - Page 372
2003 Chevrolet Tahoe Manual
Page 372 highlights
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. 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. 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. Your vehicle may have a cap with text and a graphic, or just a graphic as shown. See Engine Compartment Overview on page 5-14 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. 5-19