RADIATOR: The aluminum core radiators used in Fieros are unique and no other cars use these identical radiators. (One of the Chevette radiators is very similar except for mounting holes.) Some models of the Fiero have thinner radiators than others. The thicker model has greater cooling capacity and will swap to any Fiero. The V-6 Fiero came standard with the thicker radiator. Fieros with the four cylinder engine used both types during their production lifetime. The "thin" radiator has a size of 15" x 19.75" x 1". The "thick" radiator has a size of 15" x 19.75" x 1.375". Replacements are readily available from conventional parts suppliers. A source for radiators is Auto Radiator Outlet at 800-252-0333.
RADIATOR CAP: The radiator cap in the Fiero is a 15 PSI non-vented type and is readily available as an aftermarket item. Be careful to get the non-vented version to avoid overheating. EVERY auto parts supplier we have checked has the wrong radiator cap listed in their computer for the Fiero. Be certain to get the non-vented type. The original GM cap is preferred, Part No. 10230 (or 10036879 is the old number). AC Delco also makes a good replacement cap under their number RC27. It can be found at acdelco.com. A suitable replacement from parts stores is Stant No. 11230. We also understand that Stant has a new cap for the Fiero, No. 45819. We have not had an opportunity to verify this new version and would appreciate feedback from anyone who has.
THERMOSTAT CAP: Note that the thermostat cap is not the same as the radiator cap. The thermostat cap is available from AC Delco (acdelco.com) under their part number RC40. This cap is also available from auto parts stores.
COOLANT HOSES: The molded coolant hoses for the Fiero appear to be unique and not used on other cars. The following list of hoses by Gates Rubber should fit any V-6 Fiero although some trimming is required on some hoses. At this time we do not have information on hoses for the 4-cylinder Fiero.
Coolant Hoses for '85-87 2.8L Engine, Gates Part Numbers:
Upper - Engine to Crossover Pipe 20661 Upper - Crossover Pipe to Lateral Pipe 21532 Upper - Lateral Pipe to Radiator 21439 Lower - Lateral Pipe to Engine 21594 Lower - Radiator to Lateral Pipe 20940 Heater to Pipe-1, w/o A/C 19602 Heater to Pipe-2 Gates 18853, Delco 16078M Pipe 2 to Pipe 3 20338 Throttle Body to Pipe 5/16" x 3" Throttle Body to Engine 10820Coolant Hoses for 1988 V-6 2.8L Engine, Gates Part Numbers:
Upper - Engine to Crossover Pipe 20661 Upper - Crossover Pipe to Lateral Pipe 21763 Upper - Lateral Pipe to Radiator 21764 Lower - Lateral Pipe to Engine 21758 Lower - Radiator to Lateral Pipe 21708 Heater to Pipe-1, w/o A/C 19602, Delco 18117L Heater to Pipe-2, w/o A/C 18836 Pipe 2 to Pipe 3 20338 Throttle Body to Pipe 5/16" x 3" Throttle Body to Engine 10820
You can find a local supplier of the Gates hoses via this web site: http://www.gates.com/part_locator/reverselookup.cfm
Note that for an '88 Fiero with air conditioning there is no listing for "heater to pipe" hoses. The best solution we know is to take the old hoses to a parts store and ask the clerk to allow you to peruse all the heater hoses for a close match. We have done this successfully and found that getting longer-than-necessary hoses with a few of the necessary bends will work. We installed such hoses in our '88 and then cut them at the pipe end to suit.
Also note many Fiero owners report that removal of the hoses/pipes to the throttle body will not harm performance. In fact it is curious that these items were provided by GM. Presumably the hot coolant is routed to the throttle body to eliminate icing. Since the throttle body is unlike a carburator and has minimal venturi effect, icing should be impossible. We have never heard of icing in a Fiero throttle body. The throttle body hoses have been removed from both our '88 Fieros for years and performance has been unaffected.