1996 GMC Savana Van Owner's Manual - Page 245

What toUse Use a mixture of one-half clean water (preferably distilled) and one-half DEX-COOL (orange-colored, silicate-free) antifreezethat meets GM Specification 6277M, which won't damage aluminum parts. Use GM Engine Coolant Supplement (sealer) (GM Part No. 3634621) with any complete coolant change. If you use this mixture, you don't need to add anything else. TM Adding only plain water to your cooling system can be dangerous. Plain water, some other or liquid like alcohol, can boil before the proper coolant mix will. Your vehicle's coolant warning system is set for the proper coolant With mix. plain water or the wrong mix, your engine could get too hot butyou wouldn't get the overheat warning. Your engine could catch fire and or you others could be burned. Use a 50/50 mix of clean water and DEX-COOL (orange-colored, silicate-free) antifreeze. TM 6-21