Try ...... Get the car on hill .... (car ramps) .... Nose facing uphill
Make sure you turn the cabin heater on to FULL heat
.... re-bleed the system & keep bleeding till engine running temperature // till the thermostat is fully open
This helps getting any trapped air out of the cabin heater core .... & forces any trapped air out of the heads
IF you suspect the head gasket ..... There is a "dye test kit" that can be added to the coolant that will show this
Mike

