Try taking out your glove box and see if there is a cover behind there to take off and it should be exposed. it will take time to put it in but that's the only way.
diagram for a 92 Chevy van g20 Heater core
help me preplace heater core in 92 Chevy van g20
How do you change a heater core in 1994 chevy astro van?
How do I replace the heater core in a Chevy express 1500
Remove the water supply hoses from your 1985 Chevy heater core. Remove the heater core retaining bolts. The heater core will come out. Reverse the process to install your new heater core.
Begin by removing the water supply hoses from your 1989 Chevy heater core. Remove the heater core retaining bolts. The heater core can be removed.
Drain the water from your 1998 Chevy Astro cooling system. Remove the water supply hoses from the heater core. Remove the heater core retaining bolts. Reverse the process to install the new heater core.
The 1988 Chevy G 20 Van heater core can be found behind the passenger side kick plate. You will need to remove the kick plate in order to access the heater core.
To change the heater core on a Chevy G-30 series van, first, disconnect the battery and drain the coolant. Remove the dashboard and the heater assembly to access the heater core, which is typically located behind the firewall. Disconnect the heater core hoses, remove the mounting screws, and take out the old heater core. Install the new core, reassemble the heater assembly and dashboard, and refill the coolant before reconnecting the battery.
your heater core is bad
Take out the whole dash and then the heater core should be behind the glove box on the passenger side.
To replace the heater core in a 1985 Chevy van, start by disconnecting the battery and draining the coolant from the radiator. Remove the dashboard and the heater assembly cover to access the heater core. Disconnect the hoses and any attached components, then remove the old heater core and install the new one. Reassemble everything, refill the coolant, and check for leaks before reconnecting the battery.