since im a gm tech and got tired of this problem i bought a tool that fits on your coolant over flow tank.. You hook air to it and it sucks all the are out of the system and it will colapse the hoses and if theres a leak youll know it and hear it even if the radiator is cracked or the intake gaskets are bad... Then theres a hose that goes into the coolant bottle so when you take the are off it sucks up coolant and no air pockets.. Use this on doing radiator changes or head jobs or just to get the air out of the system so easy and takes no time at all..
