1996 Pontiac Firebird Owner's Manual - Page 268

NOTICE: When adding coolant it is important thatyou use DEX-COOL (orange-colored, silicate-free) coolant meetingGM Specification 6277111. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner at 30,000 miles (50 000 km) or 24 months, whichever occursfirst. Adding only plain water to your cooling system can be dangerous.Plain water, or some other liquid like alcohol, can boil before proper the coolant mix Your vehicle's coolant warning system isset for the proper coolant mix. With plain water or the wrong mix, your engine could get too hot you wouldn't getthe overheat but warning. Your engine could catch and you or fire others could be burned. Use a 50/50mix of clean water and DEX-COOL (orange-colored, silicate-free) antifreeze. wil. -- TM What to Use Use a mixture of one-half clean water (preferably distilled) and one-half DEX-COOL (orange-colored, silicate-free) antifreeze that meets GM Specification 6277M, which won't damage aluminum parts. Use GM Engine Coolant Supplement (sealer) (GM P r at No. 3634621) with any complete coolant change. If you use this mixture, you don't need to add anything else.