1988 chev R20 engine boiling over



Is it definitely a blown head gasket, or might it be air trapped in the cooling system? If it is air, how do I purge it?


It’s not that simple! What about a stuck thermostat, low coolant level, bad water pump, plugged coolant passages, engine coolant fans not coming on, collasped hoses, flattened radiator fins, bad radiator cap, etc?


I’ve already these options and I’m starting to fear the worst.