1970s 1970 DeVille heater core change

[rms70]

Heater water valve inlet was clogged and rusted. Figured I would flush core before installing new one and ,of course, the core leaks. Shop manual says to remove the entire blower assembly and motor but won't I also  have to remove the AC evaporator cover which  might mean opening the system? Looking at the heater core cover near the inlet and outlet tubes there appears to be  a full length vertical seam which separates the heater cover from the AC evaporator cover. Does the blower assembly split at this point? Also on the cover I see the bolts to remove but there are about 5 points where I can see a screw has been threaded through on the reverse side. I read about the 4 in car screws which are difficult to access. If I understand correctly they are for securing the core itself but do they go through the heater blower cover? Core replacement seems  straightforward but it seems as if the shop manual is a little vague on details.



                    Rob

[rms70]

If anyone is interested here's what I found.  The blower assembly does split at the heater core, so removing the blower and and part of the assembly connected to the evaporator is not necessary. To remove the part of the cover containing the core you have to remove just about everything attached to it.(I can see future problems in trying to reroute wires and hoses to original positions even with the pictures I took) The bundle of colored vacuum hoses which run thru the firewall come apart from the screwed on plastic passthrough piece as a soft rubber molded unit which connected to nipples on the back side of the plastic passthrough.  This soft rubber piece could then be pushed through the firewall. The last challenge are the 4 screws which hold the plastic "box" which houses the dampers  to control air flow and direction which is screwed into the right side of the cover but from the inside. The bottom or floor screws I could get from inside the car, one each side of the hump. The top 2 I could get by pulling the core out enough to get my hand and a wrench inside and slowly loosening. Once the screws were out the cover with the heater core screwed into it lifts out as a unit. Hope this helps someone  when their time comes.

                     Rob

[Big Fins]

I did that on my first Cadillac. A '69 Sedan de Ville. That was 45 years ago. I hope to never do it again.

[R Simone]

Sorry I just saw this one - I'm with Big Fins. I just did this a month or so ago (along with the Evaporator) on my 69 and if I never do it again it will be too soon lol.  I just kept thinking "surely I don't have to take ALL of this apart?