1998 Chevrolet Express Van Owner's Manual - Page 252

Checking Engine Oil Pull out the dipstick and clean it with a paper towel or cloth, then push it back in all the way. Remove itagain, keeping the tip down, and check the level. NOTICE: Don't add too much oil. your engine has If so much oil that theoil level gets above the upper mark that shows the proper operating range, your engine could be damaged. When to Add Engine Oil If the oil isat or below the ADD mark, 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 crankcase capacity, see "Capacities and Specifications" in the Index. The engine oil filler cap is located between the coolant recovery tank andthe air cleaner.