2003 GMC Sierra 1500 Pickup Owner's Manual - Page 394

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- 120. 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. The engineoil fill cap for the VORTEC 4800,5300 and 6000 V8 engines is located on the engine valve cover on thepassenger's side of the vehicle. On the 8100 engine, the oil fill cap is located on thefront of the engine. SeeEngine Compartment Overview on page 5- 12for 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