AC Hose - Low Side

This procedure covers the removal and replacement of the low-side AC hose on a 2023 Chevrolet Bolt EUV, including refrigerant recovery, hose replacement, and system recharge.

Warnings

Tools required

Parts

• AC Low Side Hose Assembly × 1 — Use OEM specification
• AC Line O-Ring Kit × 1 — R134a compatible O-rings
• PAG Oil for AC System × 1 — PAG 46 or as specified by compressor

Fluids

• R134a Refrigerant

Preparation

1. Ensure vehicle is parked on level ground with parking brake engaged
2. Turn off vehicle and remove 12V battery negative terminal to de-energize accessories
3. Allow AC system to equalize pressure for at least 10 minutes if recently operated
4. Verify you have EPA Section 609 certification or work under certified supervision for refrigerant handling
5. Locate the low-side AC hose running from the accumulator/drier to the compressor inlet

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to the vehicle's service ports (low and high side). Follow the recovery machine's operating instructions to completely evacuate all refrigerant from the system. Record the amount of refrigerant and oil recovered for proper recharge. Wait for machine to indicate recovery is complete and system is at atmospheric pressure.
2. 2

   Access low-side AC hose
   Open the hood and locate the low-side AC hose. On the Bolt EUV, this runs from the accumulator (located near the condenser on the passenger side) to the compressor inlet. Remove any plastic engine covers or air duct components that obstruct access to the hose connections. You may need to remove the cover screws securing plastic covers.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
3. 3

   Disconnect low-side hose at accumulator
   Using a line wrench to prevent rounding, loosen the fitting connecting the low-side hose to the accumulator/drier. Once loose, unthread by hand and carefully separate the connection. Some residual oil may drip out, so have a drip pan ready. Cap or plug the accumulator port immediately to prevent contamination.
4. 4

   Disconnect low-side hose at compressor
   Locate the connection point at the compressor inlet (typically on the lower front of the compressor). Using a line wrench, loosen the fitting and separate the hose from the compressor. Cap or plug the compressor inlet port immediately to prevent moisture and debris entry. Allow any residual oil to drain into the drip pan.
5. 5

   Remove mounting brackets if equipped
   If the low-side hose is secured by any mounting brackets or clips along its routing path, remove the mounting bolts or release the clips. Note the exact routing and bracket positions for correct reinstallation of the new hose.
   Torque spec

   Mounting Bracket Bolts24 Nm (18 lb-ft)
6. 6

   Remove old O-rings and inspect ports
   Using a pick or O-ring removal tool, carefully extract the old O-rings from both the accumulator and compressor ports. Inspect the sealing surfaces for damage, scoring, or debris. Clean the sealing surfaces with a lint-free cloth. Do not scratch or gouge the sealing surfaces.
   ⚠Be extremely careful not to damage the aluminum sealing surfaces when removing old O-rings. Any scratches will cause refrigerant leaks.
7. 7

   Prepare new AC hose
   Unpack the new low-side AC hose assembly. Verify it matches the original hose routing and has the correct fittings. Install new O-rings (supplied in kit) onto the hose fittings. Lightly coat the new O-rings with fresh PAG oil (compatible with the system compressor type). This lubricates the O-rings and aids in sealing.
8. 8

   Install new hose at compressor
   Remove the cap from the compressor inlet port. Guide the new hose fitting into position and hand-thread the connection to ensure proper alignment. Once hand-tight, use a torque wrench with line wrench to tighten the AC line fitting to specification. Do not over-tighten as this can damage the O-ring seal.
   Torque spec

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

   Install new hose at accumulator
   Remove the cap from the accumulator port. Route the hose along the original path, ensuring it does not contact hot surfaces or sharp edges. Hand-thread the fitting onto the accumulator until snug, then torque to specification using a torque wrench and line wrench.
   Torque spec

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

    Secure mounting brackets
    Reinstall any mounting brackets or clips that secure the hose along its routing path. Ensure the hose routing matches the original configuration to prevent vibration or contact with other components. Torque mounting bracket bolts to specification if applicable.
    Torque spec

    Mounting Bracket Bolts24 Nm (18 lb-ft)
11. 11

    Vacuum and leak test system
    Connect the AC service machine to both service ports. Pull a vacuum on the system for at least 30 minutes to remove all air and moisture. The system should hold vacuum without rising pressure for at least 10 minutes after the pump stops. This confirms there are no leaks in the new connections.
    ⚠If the system does not hold vacuum, there is a leak. Locate and repair before proceeding to recharge.
12. 12

    Recharge AC system
    Using the AC service machine, recharge the system with the correct amount of R134a refrigerant as specified on the underhood label (typically near the condenser). Add the appropriate amount of fresh PAG oil to compensate for oil lost during recovery and hose replacement (typically 1-2 oz for hose replacement). Follow the service machine instructions for proper charging procedure.

Reassembly

1. Reinstall any plastic covers or air ducts removed during access, torquing cover screws to specification
2. Reconnect the 12V battery negative terminal
3. Double-check that all AC line fittings are properly torqued and secure
4. Ensure the new hose routing does not contact any moving parts or hot surfaces

Verification

• Start the vehicle and turn the AC system to maximum cooling
• Verify cold air is produced from the vents within 1-2 minutes
• Use an electronic leak detector to check all new connections for refrigerant leaks
• Monitor AC system performance for proper cooling and listen for unusual noises from the compressor
• Check that system pressures are within normal range using AC gauges (typically 25-45 PSI low side at idle)
• Verify no oil residue or refrigerant leakage appears at the new hose connections after 10 minutes of operation

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