1988 chev R20 engine boiling over

engines
overheating

#1

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?


#2

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?


#3

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