2003 Chevrolet Astro Owner's Manual - Page 233

When to Add Engine Oil If the oil is at or below the ADD line, 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 5-99. The engine oil fill cap is located on the valve cover in the engine compartment on the passenger's side of the vehicle. Your vehicle may have a cap with text and a graphic or just a graphic as shown above. See Engine Compartment Overview on page5-14 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. 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. 5-16