AC Evaporator

Complete removal and replacement of the AC evaporator core, requiring full dashboard removal, refrigerant recovery, and HVAC case disassembly.

Warnings

Tools required

Parts

• AC evaporator core × 1 — Use OEM specification
• Evaporator case seal × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• Expansion valve O-rings × 2 — Use OEM specification
• PAG oil (R-12 compatible) × 1 — Use manufacturer-specified amount
• Heater hose clamps × 2 — As needed for replacement
• Dashboard fastener clips (as needed) × 1 — Use OEM specification

Fluids

• R-12
• Ethylene glycol 50/50 — 2 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Disconnect negative battery cable and wait 2 minutes for airbag system capacitor discharge
3. Recover all R-12 refrigerant from AC system using certified recovery equipment
4. Drain engine coolant into suitable container by opening radiator petcock and removing cap slowly
5. Remove both front seats to improve access to lower dashboard bolts
6. Remove steering wheel using steering wheel puller after marking alignment position
7. Document all electrical connector positions with photos or labels before disconnection

Procedure

1. 1

   Disconnect refrigerant and heater lines at firewall
   Working in engine compartment, locate AC line connections at firewall on passenger side. Disconnect liquid line and suction line from evaporator using line disconnect tools. Immediately cap all open fittings to prevent moisture contamination. Locate heater core hoses at firewall and release clamps. Disconnect both heater hoses and plug with suitable caps to prevent coolant spillage into cabin.
   ⚠Residual refrigerant pressure may remain even after recovery. Wear safety glasses and work in ventilated area.
2. 2

   Remove instrument cluster and center console
   Remove instrument cluster bezel by releasing retaining clips at perimeter. Disconnect speedometer cable at back of cluster by depressing release tab. Disconnect all electrical connectors from instrument cluster and remove cluster assembly. Remove center console by locating and removing fasteners along console sides and at rear. Lift console up and over parking brake handle, disconnecting any electrical connectors for power outlets or switches.
3. 3

   Disconnect dashboard electrical systems
   Working from driver side, disconnect all electrical connectors accessible from instrument cluster opening including light switches, headlight switch, and wiper/washer controls. Move to passenger side and disconnect glove box assembly by releasing fasteners and disconnecting glove box light. Disconnect all connectors for HVAC controls and radio. Disconnect main wiring harness connectors behind center of dashboard.
4. 4

   Remove steering column supports and disconnect shift linkage
   Locate steering column mounting bracket at firewall. Remove the fasteners securing upper and lower column supports to dashboard structure. Lower steering column carefully, supporting weight to prevent strain on intermediate shaft U-joint. The Viper is equipped with a manual transmission; no shift linkage disconnection is required at the column.
5. 5

   Remove dashboard mounting fasteners
   Locate and remove all dashboard mounting bolts. Remove fasteners at each end of dashboard where it meets door A-pillars (typically 2 per side). Remove fasteners along top edge of dashboard under windshield (typically 4-6 locations). Remove lower dashboard mounting bolts at floor pan on both driver and passenger sides. Check for additional fasteners at center tunnel area and behind instrument cluster opening.
6. 6

   Remove dashboard assembly
   With assistant supporting passenger side, carefully pull dashboard assembly rearward while checking for any remaining electrical connections or fasteners. Guide dashboard over steering column stub and parking brake handle. Lift dashboard up and maneuver out through passenger door opening. Set dashboard on padded surface to prevent damage.
7. 7

   Disconnect blower motor and actuators
   With dashboard removed, access to HVAC housing is now clear. Disconnect blower motor electrical connector. Remove blower motor mounting screws and withdraw blower motor from housing. Disconnect electrical connectors from blend door actuators and mode door actuators on HVAC case. Note position of all actuator linkages before disconnection.
   Torque spec

   Blower Motor Screws7 Nm (5 lb-ft)
8. 8

   Remove HVAC case mounting hardware
   Locate HVAC case mounting bolts securing case to firewall from interior side. Remove these mounting bolts (typically 4 locations). Remove any bracket bolts securing HVAC case to floor pan or body structure. Check for additional mounting points at top of case near windshield area.
   Torque spec

   Mounting Bracket Bolts24 Nm (18 lb-ft)
9. 9

   Separate and remove HVAC case assembly
   Carefully pull HVAC case assembly rearward away from firewall, ensuring refrigerant lines and heater hoses are fully disconnected and routed through firewall. Case may be heavy; support weight during removal. Place case on clean work surface. Note that case typically separates into upper and lower halves.
10. 10

    Disassemble HVAC case and remove evaporator
    Locate evaporator case screws around perimeter where upper and lower case halves join. Remove all case screws and carefully separate case halves. Lift upper case half away to expose evaporator core and expansion valve. Note orientation of evaporator and position of inlet/outlet tubes. Disconnect expansion valve from evaporator lines if replacing expansion valve. Carefully lift evaporator core from lower case half, noting foam seals and their positions.
    Torque spec

    Evaporator Case Screws5 Nm (4 lb-ft)
11. 11

    Install new evaporator core
    Inspect lower HVAC case half for debris, old seal material, or damage. Clean thoroughly. Install new foam seals on evaporator core in same positions as original. Apply specified amount of fresh mineral oil to new evaporator core (typically 2-3 oz distributed through inlet/outlet tubes). If replacing expansion valve, install new expansion valve to evaporator using new O-rings lubricated with mineral oil. Position new evaporator core into lower case half, ensuring inlet/outlet tubes align with case openings and all foam seals are properly seated.
    Torque spec

    Expansion Valve23 Nm (17 lb-ft)
12. 12

    Reassemble HVAC case
    Apply new evaporator case seal to mating surface of lower case half. Position upper case half over evaporator, carefully aligning case halves and ensuring no wires or linkages are pinched. Install all evaporator case screws, starting at corners and working around perimeter. Tighten screws evenly in cross pattern to avoid case warping.
    Torque spec

    Evaporator Case Screws5 Nm (4 lb-ft)
13. 13

    Reinstall HVAC case assembly to vehicle
    Lift HVAC case assembly and position against firewall, guiding evaporator tubes and heater core tubes through firewall openings. Align case mounting holes with firewall studs/holes. Install mounting bracket bolts and mounting bolts, ensuring case is properly seated against firewall before final tightening. Reconnect all blend door and mode door actuator electrical connectors and verify linkage engagement. Reinstall blower motor and secure with mounting screws.
    Torque spec

    Mounting Bracket Bolts24 Nm (18 lb-ft)

    Blower Motor Screws7 Nm (5 lb-ft)
14. 14

    Connect refrigerant and heater lines
    Working from engine compartment, install new O-rings on all AC line connections, lubricating with mineral oil. Connect liquid line and suction line to evaporator tubes at firewall. Tighten line fittings to specification. Connect heater core hoses to heater core tubes and secure with new clamps. Verify all connections are secure and properly seated.
    Torque spec

    AC Line Fittings27 Nm (20 lb-ft)
15. 15

    Reinstall dashboard assembly
    With assistant, carefully maneuver dashboard assembly through passenger door and position over steering column and parking brake. Guide dashboard into position against firewall, reconnecting main wiring harness connectors as dashboard moves forward. Install all dashboard mounting bolts at A-pillars, upper windshield area, floor pan, and center tunnel. Raise steering column into position and secure column mounting brackets. Reconnect all electrical connectors for switches, HVAC controls, radio, and instrument cluster. Reinstall instrument cluster and center console. Reinstall steering wheel in original alignment position. Reinstall front seats.

Reassembly

1. Refill cooling system with 50/50 ethylene glycol mixture to proper level, bleeding air from system
2. Evacuate AC system to 29+ inches vacuum for minimum 30 minutes to remove all moisture
3. Recharge AC system with correct amount of R-12 refrigerant per factory specifications (typically 2.5-3.0 lbs)
4. Reconnect negative battery cable and perform any necessary radio/clock resets
5. Check for proper operation of all dashboard controls, switches, and indicators
6. Verify steering wheel airbag warning light extinguishes after key-on self-test

Verification

• Start engine and verify no coolant leaks at heater core connections
• Run AC system and verify cold air production at all vents
• Check for refrigerant leaks at evaporator line connections using electronic leak detector
• Verify blower motor operates at all speeds without unusual noise
• Test all blend door and mode door positions for proper air distribution
• Monitor AC system pressures with manifold gauges to confirm proper operation (low side 25-35 psi, high side 200-250 psi at idle with 95°F ambient)
• Verify instrument cluster gauges and warning lights function properly
• Test all dashboard switches and controls for proper operation

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