• Tiny
  • Martinice

How to change heating core on a 83 cadillac deville

Do you
have the same problem?
Friday, January 21st, 2011 AT 6:26 PM

2 Replies

  • Tiny
  • Factoryjack
  • 4,262 POSTS

It is all done from under the hood. Here is the procedure. If you need illustrations, reply back and I will send what I have.


Remove electrical connections from blower motor, compressor cycling switch, power module and radio lead-in connections. Position wiring harness out of way.
Remove right-hand windshield washer nozzle.
Air Inlet Screen

Remove right-hand secondary air inlet screen from plenum.
Partially remove rubber molding above plenum (1 screw on right-hand side).
Air Inlet Screen

Remove remaining screws and remove primary inlet screen.
Remove blower motor.
Remove two screws securing compressor cycling switch to module and carefully reposition switch off of module cover.

Remove 16 screws as shown, holding A/C mode cover and remove cover.
Clamp off heater hoses and remove hoses from heater core nipples.
Remove one screw and retainer holding heater core to frame at top.
With the temperature door in the max. Hot position, reach through the temperature housing and push the lower forward corner of the heater core away from the housing. Then rotate the core parallel to the housing. This causes the core to snap out of the lower clamp. The core may not be removed in a vertical direction due to the configuration of the lower core tank, lower clamp and temperature housing.

Remove sealer from surfaces as shown, and install new sealer in positions shown.
Position heater core to frame and push core down firmly to seat in clip at bottom.
Secure heater core to frame at top with one screw and retainer.
Connect heater hoses to heater core nipples and secure with hose clamps.

Install A/C module cover and secure with screws as shown.
Position compressor-cycling switch to module cover and secure with two screws.
Install blower motor.
Air Inlet Screen

Install primary inlet screen.
Install rubber molding above plenum.
Install secondary inlet screen to plenum.
Install right-hand windshield washer nozzle.
Install electrical connections to blower motor, compressor cycling switch, power module and radio lead-in connections. Install wiring harness back to original position.
13 Refill cooling system as required.

Was this
Friday, February 11th, 2011 AT 6:28 AM
  • Tiny
  • Soldierart

Can you send me illustrations for changing heater core.

Was this
Friday, December 26th, 2014 AT 8:11 PM

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