new member

[mach 1 1971]

i have one question right now cause im trying to get my 71 mach1 back up and i think im lost i"m trying to change my heater core and i just had it painted and new interior done so i dont know where to start. i have a new core (just picked it up). can any one tell me what i have to do to change this? help help help. Dan

[thundertc64]

1. Disconnect Heater and AC hoses. (See manual on proper AC disconnection procedures.)

2. Cut drain hose from under car at bottom of firewall. You may want to save the plug that’s inside the end of the drain hose, which is there to prevent critters from entering your heater box. Note: If you bypass this step, you will likely break the fiberglass drain nipple off your heater box trying to pull it out.

3. Remove glove box door and glove box insert.

4. If you have a camera, take a picture of the vacuum hose and temperature control cable area now before disassembly. Label hoses to further aid in reassembly.

5. Disconnect: Thermostat switch wires; vacuum hoses to heater box (2) vacuum canisters; vacuum hoses to (cable controlled) water valve switch; and cable to water valve switch.

6. On the engine side of the firewall, remove 2 heater box hex/washer nuts. Easily identified by large washer and long protruding studs.

7. Remove 2 blower motor housing retaining screws (under dash center) and permit blower housing to hang (no need to remove the firewall mounting on the blower motor).

8. You may need to remove the vacuum canisters to give the heater box assembly some wiggle room during removal and installation.

9. Remove the heater box to cowl retaining screw (look up at right side of heater box).

10. Remove heater box assembly by sliding to the right (to disengage the blower fan), then down.

11. On the removed heater box, put a large screwdriver blade in the return of each metal spring clip such that you are opening up the springs to remove them. Do NOT pry the clips off by inserting the screwdriver under the clips – This will permanently damage the heater box.

Reverse to install.

Though some of the above is not included in the shop manual, if you need more info. (such as diagrams), I strongly recommend buying the full shop manual set.

[Mach 1 Club]

Welcome to the site mach 1 1971!! Hows about some pictures?!?!?

thundertc64 good posting! Thats what this site is all about!!

[thundertc64]

Thanks, had to replace mine last week. i can't remember when i had so much fun

[Rare Pony]

Welcome to the Club Mach 1 1971!

Great detailed instructions for the heater core replacement.

[Mach1Guy]

Thanks, had to replace mine last week. i can't remember when i had so much fun

Cant get much better experince then that :)

Welcome to the site mach 1 1971, hopefully when you get your heatercore replaced you shot some picture so we can check out your Mach. Good luck with the replacement

[1969jimmach]

welcome to the site mach 1971.And great job thundertc64.Again another member helps out.