1994 GMC Suburban Owner's Manual - Page 284

Adding Coolant -Diesel Engines ..." >CC - . . The coolant surge tank is located on the passenger side atthe rear corner of the engine compartment i ' To Check Coolani When your engine is cold, the coolant level should be at the COLD mark, or a little higher. When your engine is warm, the level should be above the COLD mark. If this light comes on, it means you're low on engine coolant. To Add Coolant If you need more coolant, add the proper mix ut the surge tank, but only when the engine is cool. Open the bleed valve on the thermostat housing to allow trapped air out of the system. Close the bleed valve when coolant begins to flow out. 6-38