I have a 98 k1500 305 and coolant started leaking into the cab. For a temporary fix can I clamp the 2 hoses going to it off, or will pressure build and cause problems?
you'd be better off pulling the hoses off the core and looping them to each other.
FWIW, if the fitting in the intake is NOT ZINC, that is why your heater core died, the Zinc was a sacrificial anode in the system to keep the aluminum parts ( heater core, radiator) from being eaten by the acidic Dexclog ( even regular green coolant gets acidic over time )
ya that will work. The core is actually easy to change on 95+, get 1/4" drive set lay on floor and drop the plastic cover on the bottom. Be careful to get all of the screws on the cover, if they are all out it should drop out easy. couple screws on a clip holding core in and your in the home stretch..