hvac

AC Hose Assembly

for 2014 Ram 2500 6.7L I6 Cummins Diesel · 4WD

Difficulty

Moderate

Time

3.2 h

Tools

Steps

Replace the AC hose assembly on a 2014 Ram 2500 with 6.7L Cummins diesel engine, including refrigerant recovery, hose removal/installation, and system recharge.

Warnings

⚠️AC refrigerant must be recovered by certified technician using proper equipment. Venting refrigerant to atmosphere is illegal and environmentally harmful.

⚠️AC system operates at high pressure (up to 400 psi). Always recover refrigerant before disconnecting any lines.

⚠Refrigerant contact with skin can cause frostbite. Wear safety glasses and gloves when working near AC fittings.

⚠PAG oil is hygroscopic and absorbs moisture rapidly. Keep containers sealed until use and minimize system open time.

ℹ️This procedure requires EPA 609 certification for refrigerant handling in most jurisdictions.

Tools required

AC refrigerant recovery machineEssential

Vacuum pump capable of 500 micronsEssential

AC manifold gauge setEssential

Torque wrench (5-50 Nm range)Essential

Flare nut wrench set

Socket set (metric)Essential

Trim panel removal tools

Refrigerant scaleEssential

UV leak detection kit

O-ring pick set

Parts

AC hose assembly (specify which line: suction, discharge, or liquid) × 1 — Use OEM specification
AC line O-ring kit × 1 — Use OEM specification
PAG oil for R-134a systems × 1 — PAG-46 or vehicle-specific
R-134a refrigerant × 1 — Approximately 2.75 lbs total system capacity

Preparation

Ensure engine is cold and vehicle is parked on level ground
Verify AC system operation and note any existing issues before beginning work
Gather all replacement parts and verify correct hose assembly for your specific AC line
Connect AC recovery machine and verify it is functioning properly
Have new O-rings and PAG oil ready before opening system

Procedure

1
Recover AC refrigerant
Connect the AC recovery machine to the service ports on the AC system. Follow the recovery machine manufacturer's instructions to fully recover all refrigerant from the system. Record the amount of refrigerant and oil recovered for reference during recharging. Wait for system pressure to equalize to atmospheric pressure before proceeding.
2
Access the AC hose assembly
Depending on which hose assembly is being replaced, access requirements vary. For suction/discharge lines near the compressor, access from the engine bay near the front passenger side of the engine. For lines near the firewall, you may need to remove the battery or air intake components for clearance. The compressor is mounted low on the passenger side of the engine block on the 6.7L Cummins.
3
Remove mounting brackets and clips
Identify all mounting brackets, clips, and retainers securing the AC hose assembly along its routing path. Remove any bolts or screws holding brackets to the chassis or engine. Note the exact routing and position of clips for reinstallation. Take photos if needed to document routing paths, especially where hoses pass near the engine or frame.
Torque spec
Mounting Bolts37 Nm (27 lb-ft)
4
Disconnect hose at compressor end
Using a flare nut wrench to prevent damage to the fitting, carefully loosen the AC line fitting at the compressor connection. Once loose, unthread by hand and pull the line away from the compressor. Immediately cap the open compressor port with a clean plug to prevent contamination and moisture entry. Remove and discard the old O-rings from the fitting.
⚠Even after recovery, residual refrigerant may be present. Work in a well-ventilated area.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
5
Disconnect hose at condenser or evaporator end
Locate the opposite end of the hose assembly at the condenser (for high-pressure lines) or evaporator/accumulator (for low-pressure lines). Use a flare nut wrench to loosen the fitting. For firewall connections, access may be easier from inside the cabin by removing the lower dash panel on the passenger side. Remove the line and immediately cap the open port. Remove and discard old O-rings.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
6
Remove old hose assembly
Carefully maneuver the old hose assembly out of the engine bay, following the routing path documented earlier. On the 6.7L Cummins, hoses typically route along the passenger side of the engine. Note any areas where the hose passed through grommets or protective sleeves. Inspect the old hose for signs of damage, abrasion, or contamination to identify the failure cause.
7
Prepare new hose assembly
Inspect the new hose assembly to confirm it matches the old unit in length, fitting types, and routing configuration. Lubricate new O-rings with fresh PAG oil and install them onto both ends of the new hose assembly. Ensure O-rings are seated properly in their grooves. Add the manufacturer-specified amount of PAG oil (typically 1-2 oz) into the new hose through one of the open ends to replace oil lost with the old hose.
8
Route and position new hose
Route the new hose assembly along the same path as the original, ensuring it does not contact sharp edges, hot exhaust components, or moving parts. Thread it through any grommets or protective sleeves. Position the hose so both ends align with their respective fittings without tension or kinking. Verify adequate clearance from the serpentine belt, engine mounts, and steering components.
9
Connect hose at condenser or evaporator end
Remove the cap from the condenser or evaporator port. Inspect the mating surface for damage or debris. Hand-thread the new hose fitting onto the port, ensuring the O-ring does not pinch or dislodge. Once hand-tight, use a torque wrench and flare nut wrench to tighten to specification. Do not over-tighten as this can damage the O-ring seal.
⚠Cross-threading aluminum AC fittings will cause leaks and require component replacement. Thread carefully by hand first.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
10
Connect hose at compressor end
Remove the cap from the compressor port. Hand-thread the hose fitting onto the compressor connection, ensuring proper O-ring placement. Once hand-tight, torque to specification using a torque wrench. Verify the fitting is fully seated and the hose is not twisted or under tension at this connection point.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
11
Install mounting brackets and clips
Reinstall all mounting brackets, clips, and retainers along the hose routing path. Torque bracket bolts to specification. Ensure clips are fully engaged and the hose is securely supported at all mounting points. Verify the hose cannot vibrate against the chassis or engine components. Double-check clearance from all moving parts and hot surfaces.
Torque spec
Mounting Bolts37 Nm (27 lb-ft)
12
Evacuate AC system
Connect a vacuum pump to the AC service ports. Evacuate the system to at least 500 microns and hold for a minimum of 30 minutes (45-60 minutes preferred for best results). Monitor the vacuum gauge for decay. If vacuum holds steady, the system is sealed. If vacuum decays, there is a leak that must be found and repaired before charging. After successful vacuum hold test, close service valves and disconnect the vacuum pump.
ℹ️Proper evacuation removes moisture and air from the system, which is critical for compressor longevity and cooling performance.
13
Recharge AC system
Using refrigerant scale and manifold gauges, charge the system with R-134a refrigerant. The 2014 Ram 2500 6.7L Cummins typically holds approximately 2.75 lbs of refrigerant (verify on the underhood label for exact capacity). Charge through the low-side port only with the engine running at idle and AC set to maximum cold and high blower speed. Monitor pressures and stop when the correct weight of refrigerant is added. Do not overcharge.
14
Perform leak check
With the system charged and running, use an electronic leak detector or UV dye inspection to check all connections for leaks, paying special attention to the newly installed hose fittings. Check both ends of the hose assembly and all disturbed connections. Apply leak detector around fittings while system is pressurized. If any leaks are found, recover refrigerant, repair the leak, and repeat evacuation and charging procedures.

Reassembly

Reinstall any components removed for access such as air intake tubes, battery, or trim panels
Verify all tools and parts have been removed from the engine bay
Ensure all hose routing is secure and clear of moving or hot components

Verification

Start the engine and turn AC to maximum cold with high blower speed
Verify compressor clutch engages and remains engaged
Check that cold air is produced at the vents within 2-3 minutes
Monitor AC pressures: typical values are 25-45 psi low side and 200-300 psi high side at idle with ambient temperature 70-90°F
Verify no unusual noises from the compressor or hose connections
Recheck all fittings for leaks after 10-15 minutes of operation
Test AC performance during a short test drive to verify cooling under load