you dont!you just connect both the hoses together.and wear a gloves hat and a heavy jacket!
Follow the heater hoses from the engine, they will lead you the heater core.
how do i change the heater core in a 1990 Eddie Bauer
It is located on the pass/side next to blend door/heater core
Under the dash on the passenger side
To replace the heater core in a 1989 Ford Econoline, start by disconnecting the battery and draining the coolant from the radiator. Next, remove the dashboard and the heater box to access the heater core, which is typically located behind the dashboard. Disconnect the hoses attached to the heater core, remove the old core, and install the new one in reverse order. Finally, reassemble the dashboard, refill the coolant, and check for leaks.
Sell your Ford junk its not the only problem you will have.
In order to change the heater core on an 90 ls400 you have to remove the entire dash pad and cross bar to be able to remove the heater core box. This is a job for and experienced LEXUS technician www.lextechautomotivellc.com
change out the heater core
how to change heater core in 98 suburban
Drain the water from your 1990 Chevy Corsica cooling system. Remove the heater core water supply hoses. Remove the heater core retaining bolts. Reverse the process to install the new heater core.
This process could take up to 3 hours. The Heater core is best flushed if you are having problems with flow. Is this an option? F. Garay
Have you flushed the heater core?