Replace evaporator a/c evaporator leaking refrigerant and needs to be replaced. How do I remove and reinstall new evaporator?

by getting a repair manual

This is not something that is easy, cheap or something a novice should do, you need to have special tools and training ,you have to change the receiver dryer and flush the system. That is why it costs thousands to have it done at a shop.

1. Remove the filter lid (A), then pull out the dust and pollen filters (B).
   

2. Pull out the evaporator temperature sensor (C) from the evaporator fins.
   

3. Remove the screws, carefully separate the upper housing (D) from the lower housing (E), then remove the evaporator core (F).
   

4. If necessary, remove the expansion valve (G). Use a second wrench to hold the other fitting on the valve so the evaporator line won't twist. Leave the first fitting loosely connected so you can use it to hold the valve while you loosen the second fitting.
   

5. Reassemble the evaporator in the reverse order of disassembly, and note these items:
   

   • Replace all O-rings, with new ones at each fitting and apply a thin coat of refrigerant oil before installing them. Be sure to use the right O-rings for HFC-134a (R-134a) to avoid leakage.
     
   • Immediately after using the oil, reinstall the cap on the container, and seal it to avoid moisture absorption.
     
   • Install the capillary tube (H) directly against the outlet line, and wrap it with electrical tape (I).
     
   • Reinstall the evaporator temperature sensor in its original location.
     
   • Make sure no air is leaking from the upper housing and the lower housing fitting.
     

in my experience finding specific directions on how to do that are nearly impossible to find due to the strict EPA regulations on the use of refrigerant. but when i replaced the evaporator core on my tahoe i found it helpful to go on to youtube and search how to remove the dash. once the dash is out disconect the lines going to the evaporator core and the heater core from the engine side of the firewall. from inside the vehicle remove all screws securing the heater box to the firewall. you have to search for one or two hidden screws. looking from the engine side may make them visible. the heater box should pull out easily if not you missed a screw. once out of the vechicle remove all screws hold the box halves together, mine had about fifteen going all the way around it. open it up remove the evaporator core, clean any dirt, leaves etc. out of the box. replace core and reinstall. honestly not a very difficult job, but it is time consuming. hope this helps.

Heater and Evaporator Core Housing Removal & Installation To Remove:

1. Recover the refrigerant.
2. Remove the instrument panel.
3. Remove the right side cowl vent screen.
4. Remove the screws and the water shield.
5. Disconnect the vacuum supply hose.
6. Clamp off and disconnect the heater hoses at the firewall.
7. Disconnect the evaporator outlet spring lock coupling. Discard the O-rings.
8. Remove the two condenser-to-evaporator line bracket bolts.
9. Disconnect the evaporator inlet spring lock coupling. Discard the O-rings.
10. Remove the three nuts at the dash panel.
11. Remove the screws and the heater outlet floor duct.
12. Remove the evaporator core housing bolt and nut.
13. Remove the heater and evaporator core housing.

Heater and evaporator core housing removal/installation

To Install:

1. Install the heater and evaporator core housing in the vehicle. Secure the mounting nut and bolt.
2. Install the heater outlet floor duct. Secure with the mounting screws.
3. Install the three mounting nuts to the dash panel. Tighten to 53 in-lb (6 Nm).
4. Install new refrigerant system O-ring seals lubricated in clean mineral oil. Connect the evaporator lines.
5. Install the two condenser-to-evaporator line bracket bolts. Tighten to 80 in-lb (9 Nm).
6. Connect the hoses to the heater core connections. Lubricate the coolant hoses with plain water only, if needed.
7. Connect the vacuum supply hose.
8. Install the screws and the water shield.
9. Install the right side cowl vent screen.
10. Install the instrument panel.
11. Lubricate the refrigerant system with the correct amount of clean PAG oil.
12. Evacuate, leak test and charge the A/C system.
13. Add coolant as needed.

You'll have to replace the evaporator if it leaks. The part is kind of expensive but is available aftermarket. Use 134A. I can likely post the removal procedure.

HI. Here is a complete check list that will help you trouble shot thsi issue. You will find the problem in one or more of these areas stated below.

1. Check Drive Belts - The air conditioner utilizes a drive belt that supplies power to rotate the compressor, which is basically a refrigerant pump. If the belt fails the compressor has nothing to drive it, inspect and replace as needed to restore operation. If belt is intact proceed to the next step.

2. Check for Compressor Clutch Engagement - Turn the air conditioner to the "on" position and set controls to the coldest setting. Start the engine and allow to idle. Then open the hood and inspect the clutch at the front of the compressor, is it turning? "Engaged" if so, the system has enough refrigerant to activate. If the system is low on refrigerant it will not work properly. In this case an air conditioner recharge kit is needed to recharge the system. If the system is low on refrigerant it could cycle on and off, making a ticking noise. If the compressor clutch is not turning proceed to next step.

3. Inspect for Refrigerant Leaks - If the system has a large leak and no refrigerant remains it will not activate. First test system for a static pressure charge, with the engine off attach an ac gauge to the low side pressure port and check the state of charge. Depending on outside temperature there should be between 50 psi and 80 psi. (Cool and warm). A refrigerant leak detector is needed to inspect for leak, but if you do not have a leak detector there is an alternative method. The air conditioner system is designed to run with oil suspended in the refrigerant to lubricate the system. Check for oily residue outside the system by inspecting all hoses, compressor, condenser, evaporator or receiver drier and replace any component that has failed.

4. Inspect Fuses - Check under dash panel and under hood power distribution center. Replace failed fuses as needed, recheck system. If the new fuse fails when reinstalled a short circuit is present and requires diagnosing with a wiring schematic, follow circuits to locate short, repair as needed and recheck system.

5. Check Temperature Control Vents - The vents inside your car are controlled by a cable, electrical servo or vacuum servo. If the temperature blend door is not functioning properly it will cause warm air from the heater to exit the vents. To check this start the car and allow the engine idle, next turn the blower motor speed on low, switch the temperature control from warm to cold while your ear is close to the vents. You should hear the door move inside the heater box as it swings from open to close. If not, insect for a vacuum leak or a shorted motor in the servo, repair the leak or replace the servo motor.

1. Drain the cooling system. Refer to Draining and Filling Cooling System in Cooling System.
2. Recover the refrigerant. Refer to Refrigerant Recovery and Recharging.
3. Remove the bolt connecting evaporator lines to evaporator.
4. Remove the evaporator lines from the evaporator.
5. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
6. Disconnect the heater hoses from the heater core.
7. Lower the vehicle.
8. Remove the evaporator case drain tube.
9. Remove the inside and outside module attaching bolts and the accumulator mounting bracket bolt.
10. Remove the IP carrier.
11. Remove the floor air outlet.
12. Disconnect the wiring harness from the HVAC module assembly
13. Disconnect the electrical connections at the following locations:

• The blower motor
• The blower resistor

1. Remove the HVAC module assembly screw (2) at the top of the module from the mounting bracket. (1).
2. Disconnect the gray source vacuum line (1). IMPORTANT: DO NOT tilt HVAC module assembly or coolant may leak out.
3. Remove MODULE from Vehicle

The evaporator coil is located in the heater-A/C housing, under the instrument panel.

The heater-A/C housing assembly must be removed from the vehicle and the two halves of the housing separated for service access of the heater core, evaporator coil, blend-air door, and each of the various mode control doors.

WARNING: On vehicles equipped with airbags, refer to Airbag Systems Safety Information and Procedures. Before attempting any steering wheel, steering column, or instrument panel component diagnosis or service. Failure to take the proper precautions could result in accidental airbag deployment and possible personal injury. See: Restraint SystemsAir Bag SystemsService Precautions

REMOVAL

1. Disconnect and isolate the battery negative cable.
2. Remove the instrument panel from the vehicle.
3. If the vehicle is not equipped with air conditioning, go to Step 6. If the vehicle is equipped with air conditioning, recover the refrigerant from the refrigerant system.
4. Disconnect the liquid line refrigerant line fitting from the evaporator inlet tube.

• Install plugs in, or tape over all of the opened refrigerant line fittings.

1. Disconnect the accumulator inlet tube refrigerant line fitting from the evaporator outlet tube. See Refrigerant Line Coupler for the procedures.

• Install plugs in, or tape over all of the opened refrigerant line fittings.

1. Drain the engine cooling system.
2. Disconnect the heater hoses from the heater core tubes. Install plugs in, or tape over the opened heater core tubes.
3. Unplug the heater-A/C system vacuum supply line connector from the tee fitting near the heater core tubes.

Unplug the heater-A/C unit wire harness connector, which is fastened to the heater-A/C housing next to the blower motor relay.

1. Remove the five nuts from the heater-A/C housing mounting studs on the engine compartment side of the dash panel. Remove or reposition the evaporation canister for additional access, if required.
2. Pull the heater-A/C housing rearward far enough for the mounting studs and the evaporator condensate drain tube to clear the dash panel holes.
3. Remove the heater-A/C housing from the vehicle.

INSTALLATION

1. Position the heater-A/C housing to the dash panel. Be certain that the evaporator condensate drain tube and the housing mounting studs are inserted into their correct mounting holes.
2. Install and tighten the five nuts onto the heater-A/C housing mounting studs on the engine compartment side of the dash panel. Tighten the nuts to 6.2 Nm (55 in. lbs.) .
3. If the evaporation canister was repositioned during the removal procedure, reinstall it to its proper position.
4. Connect the Heater-A/C system vacuum supply line connector to the tee fitting near the heater core tubes.
5. Unplug or remove the tape from the heater core tubes. Connect the heater hoses to the heater core tubes and fill the engine cooling system.
6. If the vehicle is not equipped with air conditioning, go to Step 10. If the vehicle is equipped with air conditioning, unplug or remove the tape from the accumulator inlet tube and the evaporator outlet tube fittings. Connect the accumulator inlet tube coupler to the evaporator outlet tube.
7. Unplug or remove the tape from the liquid line and the evaporator inlet tube fittings. Connect the liquid line coupler to the evaporator inlet tube.
8. Evacuate the refrigerant system.
9. Charge the refrigerant system.
10. Install the instrument panel in the vehicle.
11. Connect the battery negative cable.
12. Start the engine and check for proper operation of the heating and air conditioning systems.

I assume he used a leak tester and found a leak in the evap which is inside the plenum housing. Need to remove the plenum to get access to the evap. big job. If you are technical, you could remove the plenum assembly and let him replace the evap & then let you out the plenum back in. Then take back to have him evacuate and recharge system.
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SECTION 412-03: Air Conditioning 1999 Town Car Workshop Manual
REMOVAL AND INSTALLATION Evaporator Core Removal and Installation
NOTE: The evaporator core is not separately serviceable. It is serviced only with the evaporator core housing assembly.
NOTE: Installing a new suction accumulator is not required when repairing the refrigerant system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the suction accumulator.
NOTE: If an evaporator core leak is suspected, the evaporator core must be leak tested before it is removed from the vehicle. For additional information, refer to Section 412-00 .

1. Remove the evaporator core housing. For additional information, refer to Section 412-02 .

1. Transfer the components from the old evaporator core housing to the new evaporator core housing

1. Install the evaporator core housing. For additional
2. information, refer to Section 412-02

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Evaporator Core Housing Removal

1. Disconnect the battery ground cable (14301).

1. Recover the refrigerant. For additional information, refer to Section 412-00 .

1. Drain the radiator. For additional information, refer to Section 303-03 .

1. Remove the screws and the RH cowl vent screen.

1. Disconnect the vacuum hoses and the wire harness connector from the evaporative emission canister purge valve (EVAP canister purge valve) (9C915).

1. Remove the nuts and remove the evaporative emission canister purge valve.

1. Remove the heater hoses from the heater core.

1. Remove the screw and reposition the windshield washer fluid reservoir.

1. Disengage the four wire harness retainers from the top of the RH fender apron.

1. Remove the RH front wheel and tire.

1. Remove the screws from the RH fender apron and remove the fender apron.

1. Disconnect the wire harness connector from the A/C cycling switch (19E561).

1. Disconnect the wire harness connector from the blower motor (18527).

1. Disengage the wire harness connector from the retainer.

1. Disconnect the evaporator to compressor suction line from the suction accumulator/drier (19C836). For spring lock couplings disconnect and connect general procedure, refer to Section 412-00 .

1. CAUTION: To prevent damage to the fitting and the tube, use a backup wrench when removing the suction accumulator/drier.
   Disconnect the suction accumulator/drier from the A/C evaporator core.

1. Remove the clamp screw retaining the A/C accumulator mounting bracket to the A/C evaporator core housing and remove the suction accumulator/drier.

1. Disconnect the condenser to evaporator tube from the A/C evaporator core (19860). For spring lock couplings disconnect and connect general procedure, refer to Section 412-00 .

1. Remove the RH instrument panel insulator.
   • Remove the pushpins.
   • Disengage the courtesy lamp holder.
   • Disconnect the power point wire harness connector and remove the RH instrument panel insulator.

1. Remove the in-car temperature sensor hose and elbow from the evaporator housing.

1. Remove the nuts at the top of the evaporator housing.

1. Remove the nuts at the bottom of the evaporator housing.

1. Remove the screw and nut near the blower motor.

1. Remove the screws.

1. Separate the housing and remove the blower motor and A/C evaporator core.

1. Disconnect the wire harness connector.

1. Remove the evaporator core cover.