I have an 84 Capri RS with 302 and I have been having this weird problem. Ill go and drive it and when i get back theres coolant all over from being pushed out the cap. Ive bled the system with the heater on i dont know how many times and every time I shut it off and let it cool and go and restart it, it will have to be bled again. It has alot of airbubbles right before the thermostat opens and then its fine till you put the cap on and let it cool down agian, it'll do the same thing. So far Ive put on new headgaskets, and i ended up putting one on backwards so I redid it again. I know for sure their on right this time. Ive put in a new radiator, it has a new water pump from before this started. Ive put a new thermostat in, its a 180 and it acts like its working properly. I have no oil in the coolant and no coolant in the oil. Ive done a block test with the block test tool and liquid like you get at autozone and it didnt change colors. Cause I thought I had a cracked head, but that should have ruled that out. Ive done a compression test and its 115/120 all around the board. It runs good, but like when you get on it when its warm it kind of makes a loud ping/tick noise from the pass. side bank, but I think its just lifter noise. Im pretty sure of that. The next thing im gonna try is a coolant leakdown test to see if I can find a leak or something that would be sucking air. Any other ideas. Sorry for the long post, its just getting irritating for me. Thanks, Chris