1994 GMC Suburban Owner's Manual - Page 269

When to Add Oil If the oil is at or below the ADD line, then YOU'^^ need to add some oil. But you must use the right kind. This section explains what kind of oil to use. For crankcase capacity, see "Capacitiesand Specifications" in the Index. NOTICE: Don't add too much oil. your enginehas so much oil that the If oil level gets above the proper operating range, your engine could be damaged. The engine oil filler cap is located on a filler tube at the front of the engine. Just 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. 6-23