1997 Buick Riviera Owner's Manual - Page 224

8. Then replace the pressure cap. At any time during this procedure if coolant begins toflow out of the filler neck, reinstallthe pressure cap. Be sure the arrows on the pressure cap line up like this. 6. Start the engine and let it run until you canfeel the upper radiator hose getting hot. Watch for the out engine fans. 7. By this time, the coolant level inside the radiator If filler neck may be lower. the levelis lower, add more of the properDEX-COOL@coolant mixture through the filler neck untilthe level reaches the base of the filler neck. 5-23