hvac

AC Hose - Low Side

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

Difficulty

Moderate

Time

2.4 h

Tools

Steps

This procedure covers the replacement of the low-side AC hose on a 2014 Ram 2500 with 6.7L Cummins diesel, including refrigerant recovery, hose removal, installation with new O-rings, and system recharge.

Warnings

⚠️AC system operates at high pressure. Always recover refrigerant using proper equipment before disconnecting any lines. Refrigerant can cause frostbite on contact.

⚠This vehicle uses R-134a refrigerant. Do not mix refrigerant types. Ensure recovery machine is certified for R-134a only.

⚠Always use new O-rings when reconnecting AC lines. Reusing old O-rings will result in system leaks.

ℹ️AC system must be evacuated for at least 30 minutes before recharging to remove all moisture.

Tools required

AC refrigerant recovery machineEssential

Torque wrench (10-50 Nm range)Essential

Flare nut wrench setEssential

AC vacuum pumpEssential

AC manifold gauge setEssential

Socket set (metric)Essential

Ratchet and extensionsEssential

Refrigerant scaleEssential

Safety glassesEssential

Work gloves

Drain pan

Parts

AC low side hose assembly × 1 — Use OEM specification
AC line O-ring kit × 1 — Use OEM specification
R-134a refrigerant × 1 — Approximately 2.2 lbs total system capacity
PAG 46 compressor oil × 1 — Use OEM specification

Preparation

Park vehicle on level surface and engage parking brake
Turn engine off and allow AC system to sit for at least 5 minutes to equalize pressure
Verify AC refrigerant recovery machine is functioning and certified
Locate low-side AC hose routing from accumulator/drier to compressor on passenger side of engine bay
Document refrigerant charge amount from under-hood label for proper recharge quantity

Procedure

1
Recover AC refrigerant
Connect AC recovery machine to service ports on vehicle. Follow recovery machine instructions to completely evacuate all R-134a refrigerant from the system. Record the amount recovered for comparison during recharge. Ensure recovery is complete before proceeding.
⚠️Never open AC system under pressure. Verify system pressure is at zero before disconnecting any fittings.
2
Access low-side AC hose
The low-side hose runs from the accumulator/drier near the firewall on the passenger side to the compressor. Remove engine cover if equipped by lifting upward on retaining clips. For better access, remove air intake tube from air filter housing to throttle body by loosening hose clamps.
Torque spec
Hose Clamps3 Nm (2 lb-ft)
3
Disconnect low-side hose at compressor
Using a flare nut wrench to prevent rounding, loosen and remove the AC line fitting at the compressor connection. Support the hose to prevent stress on remaining connections. Remove and discard old O-rings from the connection. Expect a small amount of residual oil to drain out; catch with drain pan.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
4
Disconnect low-side hose at accumulator/drier
Locate the connection point at the accumulator/drier mounted near the firewall. Use flare nut wrench to carefully loosen the fitting. Once loose, carefully remove the line and inspect the connection point for debris or damage. Remove and discard old O-rings.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
5
Remove mounting brackets
The low-side hose is secured to the vehicle with one or more mounting brackets. Remove retaining bolts securing these brackets and carefully extract the old hose from the engine bay. Note the exact routing path and any support points for installation of new hose.
Torque spec
Mounting Bolts37 Nm (27 lb-ft)
6
Prepare new low-side hose
Remove protective caps from new low-side hose ends. Install new O-rings from kit onto both connection points of the new hose. Lightly coat each O-ring with PAG 46 oil to ensure proper seal and prevent damage during installation. Add approximately 1-2 oz of fresh PAG oil into the open hose end to replace oil lost during recovery.
7
Install new hose routing
Route the new low-side hose following the exact path of the original hose. Ensure the hose does not contact any sharp edges, hot exhaust components, or moving parts. Install mounting brackets and loosely secure bolts to allow final positioning adjustment.
Torque spec
Mounting Bolts37 Nm (27 lb-ft)
8
Connect hose to accumulator/drier
Carefully thread the fitting by hand onto the accumulator/drier connection to prevent cross-threading. Once hand-tight, use flare nut wrench and torque wrench to tighten to specification. Ensure O-ring remains properly seated during installation.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
9
Connect hose to compressor
Thread the compressor end fitting by hand until snug. Verify O-ring is properly positioned and not pinched. Use flare nut wrench and torque wrench to tighten to specification. Do not overtighten as this can damage the sealing surface.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
10
Secure mounting brackets
With both hose connections complete, verify hose routing has adequate clearance from all components. Torque all mounting bracket bolts to specification. Verify hose cannot contact moving parts through full suspension travel.
Torque spec
Mounting Bolts37 Nm (27 lb-ft)
11
Evacuate AC system
Connect AC vacuum pump to service ports using manifold gauge set. Evacuate system to at least 29 inches of mercury vacuum. Maintain vacuum for minimum 30 minutes to remove all moisture. Close valves and monitor vacuum for 10 minutes to verify system holds vacuum without leaks.
⚠Inadequate evacuation time will leave moisture in system causing corrosion and poor performance. Do not skip or rush this step.
12
Recharge AC system
Using refrigerant scale and charging equipment, add the specified amount of R-134a refrigerant as indicated on under-hood label (typically 2.2 lbs for this vehicle). Charge through low-side service port only. Monitor gauges to ensure proper pressures are achieved. Do not overcharge system.
⚠Overcharging AC system will cause poor cooling and potential compressor damage. Use scale to measure exact refrigerant amount.
13
Reinstall air intake components
Reinstall air intake tube between air filter housing and throttle body. Secure all hose clamps to specification. Reinstall engine cover if equipped by pressing down on retaining clips until seated.
Torque spec
Hose Clamps3 Nm (2 lb-ft)

Reassembly

Double-check all AC line fittings are properly torqued and O-rings are not visible
Verify all mounting brackets are secure and hose has proper clearance
Ensure all tools and parts packaging are removed from engine bay
Verify air intake system is fully reconnected and secure

Verification

Start engine and turn AC to maximum cold with blower on high
Allow system to run for 5 minutes and verify cold air is produced at all vents
Check low-side and high-side pressures with manifold gauges (low side should be 25-35 PSI, high side 200-250 PSI at idle with 75-85°F ambient)
Inspect all connection points for signs of oil residue indicating leaks
Use electronic leak detector around all fittings to verify no refrigerant leaks are present
Verify compressor clutch engages and disengages properly during operation
Check vent temperature with thermometer (should be 38-42°F with ambient temp around 75-80°F)