'76 Eldorado Heater Core

[mrmatthew]

Heater core in my '76 Eldorado started leaking...I bypassed it, the shop manual shows that most the dash has to be disassembled to replace & I plan on doing it right...But just wondering why couldn't the core be attached to the firewall with a bracket under the hood & reconnected ?

[The Tassie Devil(le)]

If only it was that easy.

These units are an integral part of the whole Climate Control System, and as everything with modern cars, nothing is simple.

Following the Shop Manual, step by step, is by far the best way to go for anyone that isn't sure of what they are doing, and even for those that do.   Nothing worse than missing a step, and having to go back over and try to rectify the oversight.

Bruce.

[Matti R]

Heater core in my '76 Eldorado started leaking...I bypassed it, the shop manual shows that most the dash has to be disassembled to replace & I plan on doing it right...But just wondering why couldn't the core be attached to the firewall with a bracket under the hood & reconnected ?

Incoming air has to flow through the core in order to get warm. If the core is installed under the hood, it would not warm the air at all.

[smokuspollutus]

The 77-92 RWD all have the core under the hood and is easy enough to replace. But on a front whee drive, the engine is offset to the rear passenger side of the engine compartment, making it basically impossible to fit the core in there.

[Matti R]

The 77-92 RWD all have the core under the hood and is easy enough to replace. But on a front whee drive, the engine is offset to the rear passenger side of the engine compartment, making it basically impossible to fit the core in there.

Seville 76-79 is RWD and does not have core under the hood.

["Cadillac Kid" Greg Surfas 15364]

Matthew,
Like a lot of people here I read the service manual;s procedures and decided that I had an easier way.  I found out the hard way that doing the change-out, step by step EXACTLY the way the service manual suggests is the easiest way.  A lot of work but if you want heat without wet feet this is what you need to do.
Greg Surfas

[jagbuxx #12944]

Yes it is a bit difficult and awkward of a job and do follow the manual. However, please note the manual states to remove the 4 bolts holding the core, Correction! There are 5 mounting bolts. The 5th is hidden a bit to the right side. Knowing this ahead of time will save you some frustration.

[joeinbcs]

I did the heater core replacement on my previous '76 Eldorado convertible, following the FSM and the advice of Gerald Loidl (https://www.eldorado-seville.com/files/tag-1974-cadillac-repair-tip.php).
My mechanical skills are fairly modest, but I did this job in the factory specified 12 hours.  The only glitch I experienced, aluded to above, was the existence of a fifth bolt...once I figured this out, it was pretty straight forward. 
I'd heard this was a terrible job, but it wasn't really that difficult as long as you take your time and label all the parts you take off.
I just kept my phone handy and took pics of every step so I'd remember how to put things back together.
Don't be afraid of this...If I can do it, anybody with attention to detail can.

[bcroe]

I have done it on most of my cars, the FWD cars being by
far the most difficult.  Probably removing the passenger
seat would help a lot. 

I loosened or removed bolts on the steering column and let
it drop to a support some inches toward the drivers (in USA)
seat.  I undid the several bolts holding the dash, but did not
disconnect anything.  I put a support wire from the door frame
to the dash right side, and just swung it out a few inches. 
That gave enough clearance (crawling on the floor) to change
the core, then just push the dash back, re secure the column. 
Worked on more than one front driver. 

Ask me how to change a rear axle without disturbing the brakes.
Bruce Roe