How do you bleed the cooling system on a 1991 Oldsmobile cutlass supreme?

Answer 1

Normally there is a drainage valve at the bottom of the radiator, possibly on the drivers side. Open the radiator cap to relieve the pressure and make sure you have a bin underneath the valve to catch the coolant. I have a 95 cutlass supreme and the capacity is 10 quarts. Not all of the coolant will drain out, as some is in the block. Filling is more tricky. On mine, there are two bleeder valves, one on the tube above the water pump, and a second above the thermostat housing. You need to fill the system until both valves (while open) show coolant full. Then close the system, start the engine and run it up to operating temperature with the heat on high, in the cabin. This will allow the coolant to circulate through the heater core as well as the engine channels. Keep an eye on the engine temperature gauge inside, as the engine runs up to temperature. You should notice the temperature climb, peak, and then fall. The falling means that the thermostat has opened and thus the coolant level dropped as the coolant spread past the thermostat. Turn off the engine, let it cool, then open both bleeder valves and top off the coolant. Repeat the procedure once or twice more until the coolant stays full. Then you are good to go. As a note, while you have the system drained, it makes sense to change the thermostat. You can get one for around $10 or so. Good luck