HEATER CORE: Two heater cores were used in the Fiero, one for cars with air conditioning, another for cars without. See photo below. The core size is the same for all years but for cars with A/C the inlet/outlet pipes on the heater core are longer and offset. The heater cores are unique and not used in other vehicles so the only source for salvaged units is another Fiero. Aftermarket units are readily available from chain auto parts stores such as AutoZone, Rock Auto, etc., as well as places such as Auto Radiator Outlet at 800-252-0333. The AC Delco heater core part number for an '84-88 Fiero with A/C is 15-60038.
A company called Ready-Aire (factory is in Mexico) makes a replacement heater core for
Fieros with A/C that works fine. We have used it successfully in our two Fieros.
This particular core is stocked by several companies under their specific part number
Ready-Aire 398203 Fedco 2-469 NAPA 3310 Four Seasons 94498 Everco 6201 Stant 90203 Murray 279157
As of 12/10/08 we found the heater core at rockauto.com for $45.89 using the Four Seasons part number 94498. We also found it at advanceauto.com for $46.99 and at autozone.com for $41.99 under the Ready-Aire number 398203.
If the heater core cannot be replaced it usually can be repaired by a competent radiator shop.
When removing a leaky heater core the hoses will often be bonded to the inlet and outlet pipes making it very difficult to remove the hoses without damaging them. Since the heater core will be replaced anyway, we suggest you use pliers, Vise Grips, etc., to squeeze the hoses at the inlet/outlet pipes, thus crushing the pipes beneath the hose and breaking the bond. You may need to crush the hose at 90 degree positions to be effective. Avoid the use of serrated jaws to protect the hoses from damage, or wrap serrated jaws with duct tape, etc., to relieve any sharp edges. With the inlet/outlet pipes crushed, removing the hoses without damaging them is a lot easier.
If you plan to replace the heater hoses also, then the fast way to remove the heater core is to cut the hoses near the inlet/outlet pipes. Just make sure you have replacement hoses in hand before you cut the hoses!