AC Hose - High Side

Replace the high-side AC hose on a 1992 Dodge Viper by evacuating the R-12 refrigerant system, removing the old hose from the compressor and condenser, installing a new hose with fresh O-rings, and recharging the system.

Warnings

Tools required

Parts

• High-side AC hose assembly × 1 — Use OEM specification
• AC line O-rings × 4 — Use OEM specification
• PAG oil for AC system × 1 — Use OEM specification

Fluids

• R-12 refrigerant

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely if recently operated
3. Verify AC system refrigerant type is R-12 (check compressor label)
4. Gather all tools and replacement parts before beginning

Procedure

1. 1

   Evacuate AC refrigerant
   Using an EPA-approved R-134a recovery machine, connect the service hoses to the high and low-side service ports. Follow the recovery machine manufacturer's instructions to fully evacuate all refrigerant from the system. Record the amount of refrigerant recovered for recharging reference. Allow system pressure to equalize to atmospheric pressure before proceeding.
2. 2

   Access high-side hose at compressor
   Open the hood and locate the AC compressor on the driver's side of the engine. The high-side hose connects to the rear discharge port of the compressor. The routing runs from the compressor toward the condenser at the front of the vehicle. Clear any wiring harnesses or hoses that may obstruct access to the connection point.
3. 3

   Disconnect high-side hose from compressor
   Using a flare nut wrench to prevent line damage, loosen and remove the high-side hose fitting from the compressor discharge port. The fitting is a threaded tube nut connection. Once loose, carefully pull the hose away from the compressor. Remove and discard the two O-rings from the connection. Cap or plug the compressor port to prevent contamination.
4. 4

   Access high-side hose at condenser
   Move to the front of the vehicle. The high-side hose connects to the condenser inlet, which is located behind the front fascia on the passenger side. You may need to reach down from above or work from below to access this connection. Trace the hose from the compressor forward to locate the condenser connection point.
5. 5

   Disconnect high-side hose from condenser
   Using a flare nut wrench, loosen and remove the high-side hose fitting from the condenser inlet. The fitting is a threaded tube nut connection. Carefully pull the hose away from the condenser. Remove and discard the two O-rings from the connection. Cap or plug the condenser port to prevent contamination.
6. 6

   Remove high-side hose from vehicle
   Note the routing of the existing hose through the engine compartment, including any mounting clips or brackets. Remove the hose from any mounting points that secure it to the engine bay. The hose is likely secured with 2-3 mounting clips along its length. Extract the complete hose assembly from the vehicle, being careful not to damage adjacent components.
7. 7

   Prepare new high-side hose
   Unpack the new high-side hose assembly and verify it matches the original in length and fitting configuration. Remove all protective caps from the new hose fittings. Install new O-rings on all four connection points (two per end). Coat each new O-ring generously with fresh PAG oil to ensure proper sealing and prevent damage during installation.
8. 8

   Route new high-side hose
   Route the new high-side hose through the engine compartment following the same path as the original hose. Ensure the hose does not contact any hot engine components, sharp edges, or moving parts. Secure the hose in any mounting clips or brackets encountered along the route. Verify adequate clearance before connecting the fittings.
9. 9

   Connect high-side hose to compressor
   Remove the protective cap from the compressor discharge port. Position the hose fitting to the compressor port, ensuring the O-rings are properly seated. Thread the fitting by hand to ensure proper engagement and prevent cross-threading. Using a torque wrench and flare nut wrench, tighten the fitting to specification. Do not overtighten as this can damage the O-rings.
   Torque spec

   AC Line Fittings27 Nm (20 lb-ft)
10. 10

    Connect high-side hose to condenser
    Remove the protective cap from the condenser inlet port. Position the hose fitting to the condenser port, ensuring the O-rings are properly seated. Thread the fitting by hand to ensure proper engagement and prevent cross-threading. Using a torque wrench and flare nut wrench, tighten the fitting to specification. Do not overtighten as this can damage the O-rings.
    Torque spec

    AC Line Fittings27 Nm (20 lb-ft)
11. 11

    Vacuum test AC system
    Connect an AC vacuum pump to the system via the service ports. Evacuate the system to at least 29 inches of mercury (near full vacuum) and hold for at least 30-45 minutes. Monitor the vacuum gauge. If vacuum holds steady, the system is leak-free. If vacuum drops, inspect all connections for leaks and retighten or reseal as needed. A proper vacuum also removes any moisture from the system.
12. 12

    Recharge AC system
    Using the AC manifold gauge set and refrigerant charging equipment, add R-134a refrigerant to the system. Charge to the OEM-specified refrigerant charge weight for this vehicle. Follow proper charging procedures: engine off for initial charge, then engine running at 1500 RPM with AC on maximum to complete the charge. Monitor system pressures throughout.
13. 13

    Leak test and verify operation
    With the system charged and running, use an AC refrigerant leak detector to check all connections made during this repair, especially the compressor and condenser fittings. Start the engine and turn the AC to maximum cold with the blower on high. Verify the compressor clutch engages, system pressures are within specification (typically 200-250 PSI high side, 25-35 PSI low side at idle with ambient temperature), and cold air is produced at the vents.

Reassembly

1. Verify all mounting clips securing the high-side hose are properly engaged
2. Ensure the hose routing provides adequate clearance from exhaust manifolds and moving components
3. Double-check both fittings are torqued to specification
4. Confirm no refrigerant leaks are detected at any connection

Verification

• Start engine and activate AC system, verify compressor engages and cold air is produced
• Check system pressures are within normal operating range using manifold gauges
• Verify no refrigerant leaks at compressor and condenser connections using leak detector
• Confirm AC performance matches pre-repair operation with proper cooling capacity
• Listen for any unusual noises from the compressor or hose vibration

More procedures for this vehicle