James
Yes,disconnect the hose from the thermostat housing and block the brass union....find a length of clear 1/2" pipe ( I used approx 8ft of old m/cycle petrol pipe ) and stuff it in the rubber heater pipe...pass the pipe over something raised ( I used a roof beam in the shed )....take off the radiator cap....gently suck the hose...you will see the liquid level rise up the pipe..followed by any air bubbles...make sure the level of liquid doesn't reach the high point..( some coolant does nasty things to your body )
Job done
John