Remove instrument panel
remove right instrument panel brace located above heater case and attached to cowl. Drain engine coolant from cooling system and remove hoses from heater core. Plug hoses and core.
Remove screw attaching air inlet duct and blower housing assembly support bracket to cowl top panel. Disconnect vacuum supply hose (Black) from in-line vacuum check valve in engine compartment.
Disconnect blower motor wiring harness from resistor and motor lead. Working under hood, remove 2 nuts retaining heater assembly to dash panel. In passenger compartment, remove screw attaching heater assembly support bracket to cowl top panel.
Remove bracket-to-dash panel retaining screw located below heater assembly. Carefully pull heater assembly away from dash panel and remove heater assembly from vehicle. Remove 4 heater core access cover attaching screws and remove access cover from case. Lift heater core and seal from case. Remove seal from heater core tubes.
October, 6, 2012 AT 6:10 PM
What you read above is out of the book and will not always work if you have an AC system.
I will explain.
Working under hood, remove 2 nuts retaining heater assembly to dash panel
These 2 nuts do need to be removed, BUT
The studs (bolts) the nuts are removed from are way too long.
The heater assembly will not come out far enough to be removed.
The bolts are blocking the heater assembly from dropping down.
Also there is no mention about the heater ducking it too must be removed.
Then let s mention all the wires, hoses and cable that are twisted loop through around over under, it s a mess,
Let s face it,
If you have a 1987 thunderbird as I do, and needed the heater core replaced,
There is no simple way to complete the R&R process without removing the dash.
It s a lot of work but well worth the extra time, get the dash out of the way take your time and while your their clean fix and replace all the old and crack gaskets seals, and if your dash is cracked send it out for repair or replace.
Do it right, set aside a couple of weeks; buy the best heater core you can
(copper not aluminum) and before you begin flush your cooling system, buy a new radiator or
Or have the old radiator cleaned out, most likely cheaper to buy a new radiator.
If you do it this way your cooling system will be new and properly taken care of will last 25 30 years.
Also you have one of the best cars made in the 80s it worth the extra time and effort.
I should add I ve been working on automobiles for more then 30 years, straight out of high Fremont school I was collage trained some 30 years ago at De Anza College just when the smog laws were coming into effect, money was good.
Don t take the simple approach, it s a nice car to it right.