1995 Buick Century Owner's Manual - Page 189
1995 Buick Century Manual
Page 189 highlights
P 6. Put the cap back on the coolant recovery tank, but leave the radiator pressure cap off. 7. Start the engine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine fan. 8. By this time the coolant level inside the r d'iator a filler neck may be lower. If the level is lower, add more of the proper mix through the filler neck until the level reaches the base of the filler neck. 5-23