68 Eldo heater core

[Andy Q]

With winter approaching, Im considering replacing the heater core, which was disconnected years before. The 1968 Shop Manual R&R procedures seem to suggest it is not too difficult. Just looking at that area of the engine though, there is a lot going on there, and I dont want to disturb all those other items that work just fine. Is it worth doing, or should I just leave the whole thing alone. Any comments?

[densie]

   Yeah...its cold in the winter!  How do you get by without heat?

[JIM CLC # 15000]

11-05-05
Andy Q. The short answer is, YES, by having a heater, your car will be safer to drive in the winter, the need for a defroster is a high priority, to say nothing of needed heat for the driver and passenger(s). I do not think that you need to, nor will you, disturb any of the near-by components in order to replace the heater core.
Good Luck, Jim

[Dave MacGregor #18998]

Hi Andy,

I replaced the heater core in my 77 Eldorado this summer by myself, of all times, but that was because a tiny pin hole suddenly developed in it, though never leaking any actual fluid, but instead letting extra moisture get in the air of the vents and cause a MAJOR fogging problems on my windows.

Now to answer you question on how easy it is and should you do it or not, let me put it this way.

First, it wasnt an easy undertaking, but if youre used to taking things apart and are a good contortionist,GO FOR IT!  It can be a very rewarding project to look back on when youre finally finihsed and like Densie also said, its a safety issue for not having heatfor the defoggers.

Now here are the steps.

1.)  I highly recommend the official GM manual for your year of Cadillac for the most straightforward and detailed directions.  Also it would be a good idea to supplement it with a Haynes manual for a second reference because believe it or not, it helped me with some actual extra photos not shown in the GM manual.

2.)  Lay everything out as you take things apart.  Mark and diagram all vacuum lines where connected so that you know where they go when you reassemble everything.  A digital camera also helps!

3.)  Dont be squeammish when your dash is nearly fully apart because it does go back together!  REALLY!!! :-)

4.)  RUN THE CAR and check for any leaks where you reconnected the hoses to the heater core.  It might not be a bad idea to get new hoses and clamps too!

5.)  Once you have the dash MOSTLY back together with the vacuum lines and vents, then stop again your work again and RUN THE CAR to check to see if you reconnected things properly.  Go through ALL the climate settings!!!

6.)  Wear safety glasses or goggles when the fan kicks on just in case you loosened any dirt inside your duct work too!  I had some surprising crud fly out in my pampered low mileage garage kept 77, but then hey, dirt gets everywhere doesnt it?

8.)  Once all checked out, then reassemble and treat yourself to a nice warm ride this fall with your best friend, wife, family member, etc. and watch the leaves turn color.

It took me a full weekend to do mine and Im very happy I did it too.  Was a challenge, but I conquered it and saved perhaps big bucks to put in a 40 some odd dollar part by myself.

My only problem I encountered was that I still temporarily have one bolt in its assigned hole without a nut on the otherside in the engine compartment.  I have its exact assigne nut, know where it goes, but havent gotten around to reaching up from underneath the vehicle yet to install it.  Leaving that for this winter when I do all my other little maintenance tweaks and stuff on the car.  I have more time then.

Good Luck and I REALLY hope you do try to take on this task.  Besides I do believe your dash may be easier than mine to work on.  I have the two piece upper and lower dash in mine  like most all late model 70s Caddys which is a pain in the     !  Makes it difficult just to change a bulb in the idiot lights!!!

Dave

[Lars Langoy]

Hi

On a 68 the heater core is removed/replaced from the engine bay, no need for dash work. Just remove the parts on the heater core housing like the power servo, blower relay etc.
The housing with the heater core (one of three housings) itself are just attached to the firewall with six screws, only the ones above the trans are hard to get but not impossible.
The core you can get at http://www.rockauto.com TARGET=_blank>www.rockauto.com for just $50 + shipping.

Regards
Lars