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1971 Mark III Heater Core Installation Question

Hello Bill,
Seems that you are the guru of these old Lincolns.
I have owned my 71 Mark III for about 25 years though it still only has 89,000 miles on it. I’m essentially the second owner as I bought it from the selling dealer’s sister. The dealer had kept it for a few years as a family vacation car before selling it to his sister and her husband. Anyhow, it has all the options offered including the sun roof and is rust free and still has a good original vinyl roof. As you can guess it has seldom sat outside much. A while ago the heater core started leaking a bit evidenced by some steam on the windshield. I looked at my 1969 Ford shop manuals and read the description of how to remove and replace the heater core, assuming that my car would be the same as a 69 Mark III but some things look different.
Do you by chance have a 71 Ford shop manual showing the procedure? Is it the same as the 69? I note just glancing at the engine side that the icing switch is off to one side vs. the center position of the 69. Also looking through the glove box with the liner removed things don’t look the same as the drawings suggest in the 69. Somehow, it looks like the whole thing can be done from the engine side or am I just getting my hopes up?
Thanks for taking the time to reply. I sure would appreciate it.
Calgary, Alberta
Greetings Leigh –
These heater cores are a fairly common item and are not as hard to replace as they appear. The only real difference between a 69 and the 70-71 is that the emission tube located at the rear of the engine connecting to each of the heads must be removed on the 70-71 to allow for removal of the heater plenum that the “Core” resides in. See the illustration below:
The 69 does not have this tube. Other obstructions that must be removed or disconnected are the oil pressure switch, the hydraulic wiper motor hoses, and any vacuum hoses, etc. The evaporator front cover should also be removed and that cover also houses the de-icing switch on all three 69-71 Marks. A previous owner may have relocated the de-ice switch on your car (as you indicate) for some reason. When these items are set aside the cover along with the core can be eased out as a unit.
I recommend using a new core as these heater cores are still available new and we sell many of these every year. Do keep your old core on hand though to use as a possible spare for future repair if necessary. I do hope that the above will assist you in your repair and if you do require any further advice or parts please contact us at any time. Calgary is well within easy shipping range for us.

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