Under dash on passenger side mounted next to firewall. It is extremely hard to get to so the labor costs involved in replacing it are high. The core itself is not that expensive but labor costs are.
replace it
The price of the heater core is around $50. The labor costs to replace it can be as high as $300. This is a very labor intensive job.
sell the car
Heater core is stopped up or thermostat is stuck open.
nIG JOB. gET A MANUAL ON YOUR CAR AND DO THE JOB CORRECTLY.
you should only have to take loose the heater hoses where they go into the firewall and of course the heater core itself
In the radiator, coolant recover tank, heater core, and inside the engine water jacket.
replace your heater hoses going into and out of the heater core. One of them is probably split.
A "heater" or a "heater core"?
CHECK BLOWER MOTOR, AND HEATER CORE BOTH INSIDE THE CAR UNDER THE DASHBOARD
watch your coolant level because antifreeze is probably leaking in your heater core, another indication of leaking heater core is greasy film on inside of your windshield and it makes it hard to defrost.
The 1996 GMC half ton pickup truck heater core can be removed by removing the heater core retaining bolts. Remove the heater core water lines. Reverse the process to install the new heater core.