Ive never heard of a plugged heater core causing the cooling system to pressurize and blow steam.


Sounds to me like either you have a massive air pocket in the system, or your headgasket is blown and is pumping combustion gasses into the cooling system.


88 4R, 350 V8, R150 5 speed Sold <...uot; />
97 4R, stock, daily driver
98 Sienna, kid and dog hauler, wife's ride