hvac

AC Hose - Low Side

for 2017 Ford F-150 5.0L V8 Coyote · RWD

Editorial review:Chris Hackleman — Master Technician · 20+ years · Jeff Moore — Master Lexus & Toyota Mechanic · 20+ years

Difficulty

Moderate

Time

2.0 h

Tools

Steps

✓Expert-verified. Personally reviewed and approved by OLP's master technicians (Chris Hackleman & Jeff Moore — 20+ years each). Always follow the vehicle's factory service information and torque specs.

This procedure covers replacement of the low-side AC hose on a 2015-2020 Ford F-150 with 5.0L V8 Coyote engine, including refrigerant recovery, hose removal, installation with new O-rings, and system recharge.

Warnings

⚠️AC system operates under high pressure. Always recover refrigerant using proper equipment before disconnecting lines. Escaping refrigerant can cause severe frostbite.

⚠R-134a refrigerant is harmful to the environment. Federal law requires proper recovery and handling by certified personnel.

⚠Engine must be completely cool before beginning work. Hot components near AC lines can cause burns.

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

Tools required

AC refrigerant recovery machineEssential

Vacuum pump for AC systemEssential

AC manifold gauge setEssential

Torque wrench (10-50 Nm range)Essential

Socket set (metric)

Flare nut wrench setEssential

Trim panel removal tools

Safety glassesEssential

AC refrigerant scaleEssential

Digital thermometer

Parts

Low-side AC hose assembly × 1 — Use OEM specification
AC line O-rings × 4 — Use OEM specification
R-134a refrigerant × 1 — Typically 1.5-2.0 lbs total system capacity
PAG 46 oil for AC system × 1 — Use OEM specification

Preparation

Park vehicle on level ground and engage parking brake
Allow engine and AC system to cool completely (minimum 2 hours)
Disconnect negative battery cable and wait 2 minutes
Verify AC recovery machine is functioning properly and has adequate tank capacity
Locate low-side AC hose routing from evaporator to compressor on driver side of engine bay
Place fender cover to protect paint during work

Procedure

1
Recover AC refrigerant
Connect AC recovery machine to both high and low-side service ports. Follow machine instructions to fully recover all refrigerant from the system. Wait until system pressure reads 0 PSI on both sides. Document amount of refrigerant and oil recovered for proper recharge calculations.
2
Remove engine cover
Remove plastic engine cover by pulling upward on all four corners to release grommet fasteners. Set cover aside in clean area.
3
Access low-side hose at evaporator
Locate the low-side hose connection at the evaporator outlet near the firewall on driver side. Remove any wire harness clips or brackets securing the hose routing. Use trim tools if necessary to access hidden clips behind inner fender liner.
4
Disconnect hose at evaporator
Using flare nut wrench, carefully loosen the AC line fitting at the evaporator outlet. Use a backup wrench on the evaporator port to prevent twisting the aluminum tubing. Remove fitting completely and immediately cap the evaporator port to prevent moisture and debris entry. Remove and discard old O-rings.
5
Disconnect hose at accumulator/drier
Trace the low-side hose to the accumulator/drier connection point. Using flare nut wrench, loosen and remove the line fitting. Use backup wrench to hold accumulator port steady. Cap the accumulator port immediately. Remove and discard old O-rings.
6
Remove hose mounting brackets
Locate all mounting brackets securing the low-side hose along its routing path. Remove mounting bracket bolts and detach hose from vehicle. Note exact routing and bracket positions for proper reinstallation.
Torque spec
Mounting Bracket Bolts30 Nm (22 lb-ft)
7
Remove low-side hose assembly
Carefully maneuver the complete low-side hose assembly out of the engine bay, working around obstacles. Pay attention to routing path and take photos if necessary for reference during installation.
8
Prepare new hose assembly
Unpack new low-side hose assembly and verify correct part number and routing configuration. Install new O-rings on both ends of the new hose. Lubricate all O-rings with clean PAG 46 oil appropriate for R-134a systems. Add approximately 1 oz of fresh PAG oil into one end of the new hose to replace oil lost during hose failure.
9
Install new hose assembly
Route new low-side hose assembly through engine bay following exact path of original hose. Ensure hose does not contact sharp edges, hot exhaust components, or moving parts. Verify adequate clearance from all potential interference points.
10
Connect hose at accumulator/drier
Remove cap from accumulator port and verify port is clean and free of debris. Hand-thread the AC line fitting onto accumulator until snug, ensuring O-ring seats properly. Use flare nut wrench and torque to specification while holding accumulator port with backup wrench.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
11
Connect hose at evaporator
Remove cap from evaporator port and verify port is clean. Hand-thread the AC line fitting onto evaporator outlet until snug, ensuring proper O-ring seating. Use flare nut wrench and torque to specification while using backup wrench on evaporator port.
Torque spec
AC Line Fittings20 Nm (15 lb-ft)
12
Secure hose mounting brackets
Install all mounting brackets along hose routing path in original positions. Ensure hose is properly seated in each bracket without stress or binding. Torque mounting bracket bolts to specification.
Torque spec
Mounting Bracket Bolts30 Nm (22 lb-ft)
13
Vacuum system
Connect vacuum pump to AC system service ports. Pull vacuum on system for minimum 45 minutes to remove all moisture and air. System should hold vacuum at 28-29 inches Hg. If vacuum drops more than 2 inches in 10 minutes after pump shutoff, locate and repair leak.
14
Recharge AC system
With system under vacuum, connect refrigerant supply to low-side service port. Charge system with R-134a refrigerant to specification (typically 1.75 lbs for 5.0L F-150). Use refrigerant scale for accurate measurement. Follow proper charging procedure starting with liquid charge into low side, then vapor charge with engine running if needed.

Reassembly

Reinstall engine cover by aligning grommets with mounting posts and pressing firmly
Reconnect negative battery cable and tighten securely
Reinstall any wire harness clips or brackets removed for access
Remove fender cover and clean any spilled PAG oil from engine bay

Verification

Start engine and turn AC to MAX with fan on high speed
Verify compressor clutch engages and system operates smoothly without unusual noises
Check all AC line connections for leaks using electronic leak detector or soap solution
Monitor low-side pressure (should be 25-35 PSI at idle with ambient temp 70-80°F)
Verify vent temperature reaches 38-42°F within 5 minutes of operation
Inspect entire low-side hose routing for proper clearance and no contact with moving or hot components
Test drive vehicle and verify AC performance remains consistent under load
Recheck all connections after 24 hours of operation for any weeping or oil residue indicating leaks

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