you have to open the bleeder screw on the housing with the car running until the fluid runs clear of air bubbles
The manual isn't clear and it probably doesn't make a difference. After running long enough that the lower radiator hose is hot, meaning full flow circulation with an open thermostat, part of any air will have bubbled back to the radiator. The bleeding releases what'* trapped right at the termostat housing.
This the procedure listed. My concern about opening the bleeder valve when the engine is not running would be the possibility of introducing air back into the system.
1. Fill the radiator and the coolant reservoir to the full cold line with GM Goodwrench DEX-COOL or Havoline DEX-COOL. To ensure sufficient engine cooling, freezing and corrosion protection, maintain the protection level at -37°C (-34°F) lower.
2. Wait for two minutes and recheck the level of the coolant in the radiator. If necessary, add coolant to radiator until the coolant level is at the base of the radiator fill neck.
3. Install the radiator pressure cap, making sure the arrows on the cap line up with the coolant recovery tube.
4. Place the heater and A/C control in any A/C mode except Max and the temperature in the highest setting.
5. Start the engine and allow to idle until the lower radiator to coolant pump hose is hot.
6. Cycle the engine speed up to about 3000 RPM and back to idle five times. Slowly open the bleed valve on the top of the thermostat housing for approximately 15 seconds to expel any trapped air in the cooling system.
7. Close the air bleed valve. Do not overtighten.
8. Allow the engine to cool to outside temperature. Ensure the coolant level in the reservoir and the radiator are at the proper levels.
well, I ran it and its back to operating at about 200 degrees. The heat is so hot, it ran me out of the car! Thanks for all of your posts guys
Since it had been running cold, it may have collected a lot of condensates in the oil that didn't burn off. I'd do an oil change to get the diluted oil out. Give the dipstick the whiff test to see if it'* got a lot of gas smell to it.