Exploded Heater Core 66 289 Coupe, AT.

Yep, do the 4 core now too...

BTW, Sometimes CLEANING is the death of old radiators...

heater cores in the early Mustang are real easy. Pull the glove box out, pull the passenger seat out, disconnect the heater plenum and assorted clips and wires, pull out the box, and replace the core...or, better yet, Mustangs Unlimited (or just about any "quality" Mustang parts supply house) make new plenums, along with kits for swapping out your hold heater core....If you can change a tire, or a light bulb, and you can follow instructions, you can do an early heater core in about 1.5 hours from start to finish. My advice is to get that kit, replace it, along with your heater hoses and radiator hoses, then go from there. Unless your car is overheating, leave the stock radiator alone. Only fix the problems, don't try to reinvent the wheel, or overreact, all in one shot...............

Bill S.

Just Me "Koi" wrote:

Don't go for the 4 row radiator. If you are not overheating stay with the 3 row. The 4th row just cuts down on air flow and the extra tubes don't help much.

Any Mustang supply house will have a heater core in stock. Heck even NAPA may have one. Buy new heater hoses at the same time. The originals were thicker wall so buy those from a Mustang shop if you want them to fill the firewall holes properly. While you are at it, order the molded plastic defroster plenum. Your original is made of molded paper and will be bent and distorted. If your defroster lever feels rough, your plenum is shot and new one is a big improvement. Also order a heater box rebuild kit. This includes a lot of foam gaskets that will make the box like new.

How to change it. Drain coolant. Inside the car disconnect the wiring connector from the heater box. disconnect the 3 wire cables from the box. Pull off the 2 defroster hoses. With a socket and ratchet with extension, reach up and undo the screw that holds the box to the cowl box. This screw is very near the tophat in the cowl.

Cut off the two heater hoses under the hood of the car. Remove the 4 nuts that are retaining the heater motor to the firewall. These are accessed from under the hood. Sometimes they are really buried in sealant and goo.

Now go back under the dash and pull the box forward and down and out.

Installation is the reverse of above.

Erich

Thank you!

-- _______________________________________ "The difference between 'involvement' and 'commitment' is like an eggs-and-ham breakfast: The chicken was 'involved' - the pig was 'committed'."

Thank you Bill.

-- _______________________________________ "The difference between 'involvement' and 'commitment' is like an eggs-and-ham breakfast: The chicken was 'involved' - the pig was 'committed'."

Thank you.

-- _______________________________________ "The difference between 'involvement' and 'commitment' is like an eggs-and-ham breakfast: The chicken was 'involved' - the pig was 'committed'."

Thanks Jim!

-- _______________________________________ "The difference between '> >