1994 Cadillac Fleetwood Owner's Manual - Page 242

1. You can remove the coolant surge tank pressure cap when the cooling system, includingthe coolant surge tankpressure cap and upper radiator hose, is no longer hot. Turn the pressure cap slowly about one-quarter turn to the left and then stop. - ~ I If you hear a hiss, waitfor thatto stop. A hiss means there is stillsome pressure left. 2. Then keep turning the pressure capslowly, and remove it. 3. Fill the coolant surge tank with the proper mix, up to thebase of the filler neck.