AC Hose - High Side

This procedure covers the replacement of the high-side AC hose on a 2014-2018 Chevrolet Silverado 1500 with the 5.3L V8 engine, including refrigerant recovery, hose removal, installation with new O-rings, and system recharge.

Warnings

Tools required

Parts

• AC high-side hose assembly × 1 — Use OEM specification
• AC line O-ring kit (assorted sizes) × 1 — Use OEM specification
• R-134a refrigerant × 1 — Approximately 2.2 lbs total system capacity
• PAG 46 oil for AC system × 1 — Use OEM AC oil specification

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely if recently operated
3. Verify you have EPA certification and proper recovery equipment before beginning
4. Identify the high-side AC line routing from compressor to condenser (passenger side of engine bay)
5. Take photos of hose routing and bracket locations for reference during installation
6. Ensure AC recovery machine is properly connected and functional

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to service ports (low side at accumulator, high side near firewall). Follow machine instructions to completely recover all R-134a refrigerant from the system. Machine should indicate zero pressure and successful recovery. Record the amount of refrigerant and oil recovered for recharge reference. Allow system to equalize to atmospheric pressure before proceeding.
   ⚠️Never attempt to remove AC lines while system contains refrigerant. Verify zero pressure before loosening any fittings.
2. 2

   Remove engine cover if equipped
   If your Silverado has a plastic engine cover, grasp firmly and pull upward to release from mounting grommets. Set aside in a clean area.
3. 3

   Disconnect high-side line at compressor
   Locate the high-side AC line connection at the compressor on the passenger side of the engine. Use a flare nut wrench to loosen the fitting at the compressor discharge port. Remove the bolt or spring lock coupling as applicable. Cap or plug the compressor port immediately to prevent moisture and debris entry. Inspect and discard the old O-rings.
   ⚠Use flare nut wrenches to prevent rounding off the soft aluminum fittings. Standard open-end wrenches will likely damage the fittings.
4. 4

   Disconnect high-side line at condenser
   Access the condenser connection in front of the radiator. The high-side line connects to the outlet side of the condenser. Use a flare nut wrench to loosen the fitting. Remove any mounting brackets securing the line to the chassis or radiator support. Cap or plug the condenser port immediately. Remove and discard old O-rings.
5. 5

   Remove high-side hose assembly
   Release any remaining clips, brackets, or ties securing the high-side hose along its routing path. Note the position of any mounting brackets for reinstallation. Carefully maneuver the hose assembly out of the engine bay, avoiding contact with sharp edges or hot components. Inspect the removed hose for signs of damage, abrasion, or leakage to confirm replacement is necessary.
6. 6

   Prepare new high-side hose
   Remove protective caps from new AC hose. Install new O-rings (supplied with hose or from O-ring kit) onto both ends of the new hose. Lightly coat each O-ring with fresh PAG 46 oil using a clean applicator. Do not use petroleum-based lubricants. Add approximately 1-2 oz of PAG oil into the hose through one fitting to replace oil that was removed with the old hose.
   ⚠O-rings must be lubricated with PAG oil only. Petroleum products will damage AC system seals.
7. 7

   Install new high-side hose
   Route the new high-side hose assembly along the same path as the original, ensuring it does not contact any moving parts, hot surfaces, or sharp edges. Position any mounting brackets in their original locations. Verify the hose has adequate clearance from the serpentine belt, exhaust manifolds, and steering components.
8. 8

   Connect hose at condenser
   Remove the protective cap from the condenser outlet port. Verify the new O-ring is properly seated in the fitting groove. Hand-thread the AC line fitting onto the condenser port, ensuring it threads smoothly without cross-threading. Use a flare nut wrench and torque wrench to tighten to specification.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
9. 9

   Connect hose at compressor
   Remove the protective cap from the compressor discharge port. Verify the new O-ring is properly seated in the fitting groove. Hand-thread the AC line fitting onto the compressor discharge port, ensuring proper alignment. Use a flare nut wrench and torque wrench to tighten to specification. Do not over-tighten as this can damage the aluminum threads.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
10. 10

    Secure mounting brackets
    Install and tighten all mounting brackets and clips that secure the AC line to the chassis, radiator support, or engine. Verify the hose is properly supported and does not have excessive slack or tension. Double-check clearance from moving and hot components.
    Torque spec

    Mounting Bracket Bolts30 Nm (22 lb-ft)
11. 11

    Evacuate AC system
    Connect vacuum pump to AC system service ports. Evacuate the system to remove all air and moisture. Run vacuum pump for a minimum of 30-45 minutes to achieve deep vacuum (28-30 inches Hg). After evacuation, close valves and monitor vacuum gauge for 15 minutes - vacuum should hold steady indicating no leaks. If vacuum drops, locate and repair leak before proceeding.
    ⚠Inadequate evacuation will leave moisture in the system, causing corrosion and compressor damage. Ensure proper vacuum time and hold test.
12. 12

    Recharge AC system
    Using the AC machine or manifold gauge set, recharge the system with the correct amount of R-134a refrigerant (approximately 2.2 lbs for this vehicle - verify on underhood label). Add refrigerant through the low-side port with engine running and AC on MAX. Monitor pressures during charging. If using UV dye for leak detection, add appropriate amount during recharge process.

Reassembly

1. Reinstall engine cover by aligning grommets and pressing down firmly until seated
2. Verify all AC line connections are tight and all mounting brackets are secured
3. Check that all tools and parts have been removed from engine bay
4. Close hood and ensure no obstructions

Verification

• Start engine and turn AC to MAX cold with blower on high. Allow system to run for 5-10 minutes
• Verify cold air is blowing from vents (typically 38-42°F at center vent)
• Check high-side pressure (should be approximately 200-250 PSI at 80-90°F ambient) and low-side pressure (should be approximately 25-35 PSI)
• Inspect all AC line connections for signs of refrigerant leakage using leak detector or soap solution - no bubbles should appear
• Listen for unusual noises from compressor indicating system issues
• Verify compressor clutch engages and disengages properly
• Check that AC line routing has adequate clearance and is not contacting hot or moving components
• Test AC performance during a brief road test to ensure proper cooling under load

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