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How to Replace the A/C Evaporator
Eldorado/Seville 1992

By Stefan Knappe

First of all I'd like to say that the genuine Cadillac workshop manual is NOT correct in some aspects describing the removal of the evaporator core. At least this applies to my 1992 Eldo German spec.

Here's how I'd recommend to do it:

Recover refrigerant (if not lost already).
Drain coolant (drain cock at left bottom of radiator). Engine should not be hot.  
Remove radiator filler cap.
Remove strut support bar from left and right strut tower.
Remove MAT-sensor connector and bracket from rear valve cover and lay aside.

Separate heater hoses at T-connector above valve cover. Leave the bulkhead heater core connections alone.  It is not necessary to disturb them. (Factory manual says remove them, but they're wrong).  Move the hoses out of the way.

Disconnect power module connector and remove module (three screws).

Disconnect blower motor and remove screws (five). You will notice that there's not enough space to get the blower out. Look at casing around blower motor: You will see a script telling you to cut the sound insulation in case you want to remove the blower motor.  Do so, cut along three channels shown.  Cut through to blower opening, but leave the 'flaps' attached to bulkhead side.  Lifting the 'flaps', you will see a screw holding a little cover.  Remove this screw, remove cover and slide out blower motor with fan attached, (the manual does not describe this procedure. They say you should tilt the blower motor with fan, and separate the fan from the blower motor. I found this is not possible). Refer to drawing below, cut along the red lines, do not cut at green lines.

Remove heat shield, two screws from above, two screws from below. Pull down heat shield above catalytic converter.  Be careful, heat shield has sharp edges!

Disconnect the electrical connector from the pressure switch on evaporator line.

Unscrew the refrigerant lines from the evaporator.  

Remove clamp from upper refrigerant line, pull line out and move out of way upwards. Remove evaporator line retaining bracket (3 + 1 screw).

Remove wiring loom bracket screws from rear valve cover.

Remove screws from evaporator casing all around. Note where they belong. Leave alone three screws above and below heater hoses! You don't need to take them out, and they are bears to get at!! Ask me how I know... (The manual does not tell you this)

Cut the sound insulator from top to bottom where shown, approximately where the evap lines emerge from the casing. It's written in front of the casing "cut here to remove barrier". (The manual does not tell you) Refer to drawing below, cut along red line.

Reach down and remove electrical connector from power steering line, right below the evap casing.

Remove the sound insulator. Then you will see two screws under the remaining part of the sound insulator. Remove these screws.

Feel at the underside of the casing, or use a mirror: There's one plastic clip which still retains the cover to the bulkhead. Push in the tags on the left and right side of the clip, and the evaporator cover can be taken out.

Pull out the evaporator. Remove the pressure switch from the evap line. Pull out five plastic clips which fix a plastic gauze to one side of the evaporator.

It is a good idea to change the spark plugs at this stage, you will never again be able reach them so easily!

Now start putting it all back together....
 
Remarks:
I did not know about the fact that there's a hidden opening to remove the blower motor. I couldn't get it out, so I decided to remove the rocker cover. This is NOT a good idea. Leave the rocker cover alone if possible. It is very difficult to remove and install. Once I had the screws off, I couldn't put it back together without removal, 'cause the gasket fell out. This cost me several hours, including a trip to the dealer to get a new gasket.
The removal of the heater hoses at the bulkhead is very time consuming, as they hard to get at.  Leave them alone!
The manual also says that there is a "diverter valve" on the rear valve cover. My car was not equipped so. Your car might be, I can't say anything about removing this item.
Do not forget to add refrigerant oil to the replaced component.  In case of the evaporator, the manual states 90ml (3 oz.).  This oil should be added into the evap.
 
I hope someone can use these instructions.  If I had known the "hidden" secrets, I could have done it in half the time.  I'd guess the whole job can be done in about six hours.

All what is written here is from my own experience, with my own car. There may be different versions of cars, so the procedures may vary.  I can not be responsible for errors, though I tried to do my best to avoid any.
I would suggest that this job should only be carried out by someone who has experience repairing cars. This in no job for a beginner!

For reference: My manual is published by GM Detroit, dated 4/92.