2003 Chevrolet Blazer Owner's Manual - Page 277

A The engine oil fill cap is located in the engine compartment toward the passenger side of the vehicle. 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 5-94. See Engine Compartment Overview on page 5- 12 for more information on the location of the engine oil fill cap. 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. 5-14