1996 Buick Park Avenue Owner's Manual - Page 272

What to Use NOTICE: When adding coolant it important thatyou use is DEX-COOL (orange-colored, silicate-free) coolant meeting GM Specification 6277M. 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) or24 months, whichever occurs first. TM Use amixture 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 Part No. 3634621) with any complete coolant change. If you use this mixture,you don't need to add anything else. TM --