1998 Chevrolet Astro Owner's Manual - Page 274

When to Add Engine Oil If the oil is at or below the ADD line, then you'll need to add at leastone quart of oil. But you must the use right kind. This part explains what kind of oil to use. For crankcase capacity, see "Capacities and Specifications'' in the Index. What Kind of Engine Oil to Use Oils recommended for your vehicle be identified by can looking for the "Starburst" symbol. This symbol indicates that the oil has been certified by the American Petroleum Institute (API). Do not use any oil which does not carry this Starburst symbol. If you change your own oil, be sure you use oil that has the Starburst symbol on the front of the oil container. If you have your oilchanged for you, be sure the oil put into your engine is American Petroleum Institute certified for gasoline engines. I NOTICE: Don't add too much oil.If your engine has so much oil that the oil level gets above the shows the proper cross-hatched area that operating range, your engine could be damaged. Be sure to fill it enough to put the level somewhere in the proper operating range. Pushthe dipstick all the way back in when you're through. You should also use the proper viscosity oil for your vehicle, as shown in the following chart: 6-12