1995 Buick Riviera Owner's Manual - Page 196
1995 Buick Riviera Manual
Page 196 highlights
When the coolant in the coolant recovery tank is at FULL COLD, start your vehicle. If the overheat warning continues, there's one more thing you can try. You can add the propercoolant mix directly to the radiator but be sure the cooling system is cool before you do it. 5-15