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85&88 SEVILLES, 90 DEVILLE'S (2)
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Discussion Starter #1
Hi guy!

My 85 Seville is leaking coolant on the front passenger floor. 99% certain it's the heater core. I have the factory service manual and have done this remove/replace job on other cars both GM and Ford.

Any advice you can share on HOW to access the heater core is most appreciated. The FSM says to "remove the instrument panel - see sec 8C." But the manual only provides detailed instructions for 85 Deville/Fleetwood, and gives piecemeal R&R directions for Seville/Eldorado.

I will document and post pics of the job to help my fellow Cadillac-ers.

regards,
Ed in MD
 

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85&88 SEVILLES, 90 DEVILLE'S (2)
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29 Posts
Discussion Starter #2
Job is done, here's what I learned.

1 heater case bolt is hard to see because it's behind the heater hoses at the firewall. Look hard and you'll see it.

1 bolt is inside the AC evaporator case - you have to remove the climate control power module from the evap case to get at this bolt.

Take note of the exact position of the white nylon pin/clip at the top of the programmer - this pin/clip connects the programmer to the threaded metal rod that moves the air door.

Be very careful when removing the programmer - the motorized arm at the top is only thin plastic and can be broken easily.

The engine computer, ac programmer, and warning chime module all have to come out.

Then the entire heater case can be removed from the car, after removing the vacuum line manifold from ac programmer.

No need to drain the radiator - yeah you'll lose some coolant but not that much - less than a quart.

Upper dash pad does NOT have to come off - the lower dash trim panel does have to come off (this is the trim panel that hold the ashtray assembly.)

Remove both front seat so you have working room. Pull the carpet out entirely - nows a great time to clean it, wash it. disinfect. Rinse out the underpadding to remove the coolant that was leaking.

Now is also a good time to pull the headliner out (after the seats and carpet are out). Access is great and the h-liner comes right out of the car.

Get some "Pug Duct Seal" online or at Radioshack? to seal the openings at the firewall where the pipes come through.

Good luck!
 

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1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
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6,738 Posts
This should be a saved post or "sticky" because its true for an Eldo or Seville. From 1980 to 1985
 
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