🔧 GLE - A/C Compressor Replacement

Replacing the A/C compressor means removing the drive belt, disconnecting the refrigerant lines, swapping the compressor, then evacuating and recharging the A/C system. The most important part is handling refrigerant correctly—this job requires proper recovery/evacuation equipment to prevent system damage and stay safe.

Difficulty Level: Advanced | Estimated Time: 3-6 hours

Assumption: Your GLE uses R-134a and the compressor is belt-driven (typical for this model).

---

⚠️ Safety & Precautions

• ⚠️ Refrigerant is high-pressure and can cause frostbite/blindness—use nitrile gloves and safety glasses.
• ⚠️ Do not vent refrigerant—recover it with proper equipment before opening any A/C line.
• ⚠️ Keep hands clear of the belt path; the tensioner is spring-loaded.
• ⚠️ Let the engine cool before working near the radiator and exhaust.
• 🔋 Disconnect the battery negative terminal before unplugging the compressor electrical connector.
• 🧼 Cap/plug A/C lines immediately after opening them to keep moisture out (moisture + refrigerant can form acids).

---

🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Trim clip removal tool
• Flathead screwdriver
• Ratchet (3/8")
• Ratchet (1/2")
• Socket set (8mm-18mm)
• Torx socket set (T25-T45)
• External Torx socket set (E10-E14)
• Serpentine belt tool (17mm) (specialty)
• Torque wrench (10-100 Nm)
• Torque wrench (40-200 Nm)
• Line caps/plugs assortment
• A/C manifold gauge set for R-134a (specialty)
• Refrigerant recovery machine (specialty)
• Vacuum pump (specialty)
• Refrigerant scale (specialty)
• UV leak detection light (specialty)

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• A/C compressor (correct for your GLE) - Qty: 1
• A/C compressor O-ring seal kit - Qty: 1
• A/C refrigerant (R-134a) - Qty: As needed (charge by underhood label)
• A/C compressor oil (PAG oil to Mercedes-Benz spec for R-134a) - Qty: As needed
• Serpentine belt - Qty: 1 (recommended if belt shows cracks/glazing)
• Receiver/drier or desiccant element - Qty: 1 (recommended if system was open to air)

---

📋 Before You Begin

• Park on level ground, set the parking brake, and chock the rear wheels.
• Confirm the refrigerant type and factory charge amount on the underhood A/C label (you will recharge by weight).
• Plan to recover refrigerant before loosening any A/C line. (Recovery machine pulls refrigerant into a tank safely.)
• Disconnect the battery negative terminal once the vehicle is safe and cooled down.
• If you’ll replace the receiver/drier, do it after compressor replacement and keep it sealed until install.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Recover the refrigerant (required)

• Connect the A/C manifold gauge set for R-134a (specialty) to the high- and low-side service ports.
• Use the refrigerant recovery machine (specialty) to recover the system completely.
• Verify both gauges read ~0 psi before continuing.

Step 2: Disconnect battery power

• Open the hood.
• Use an 8mm socket to disconnect the negative battery terminal.
• Tip: Wrap the cable end to prevent contact.

Step 3: Raise the front of the vehicle for access

• Use a floor jack (rated 3-ton minimum) to lift the front at the correct jacking point.
• Support with jack stands (rated 3-ton minimum).
• Use a trim clip removal tool and Torx sockets (T25-T45) to remove the lower engine splash shield/undertray.

Step 4: Remove the drive belt from the A/C compressor

• Note the belt routing (take a photo).
• Use the serpentine belt tool (17mm) (specialty) (a long handle tool that safely rotates the tensioner) to rotate the tensioner and relieve belt tension.
• Slip the belt off the A/C compressor pulley, then slowly release the tensioner.

Step 5: Unplug the compressor electrical connector

• Locate the compressor connector (usually at the rear/top of the compressor body).
• Release the lock tab with a flathead screwdriver, then pull the connector straight off.

Step 6: Disconnect the A/C refrigerant lines at the compressor

• Place a rag under the fittings.
• Use the correct External Torx sockets (E10-E14) or Torx sockets (T25-T45) (varies by production) to remove the line retaining bolts.
• Gently wiggle the lines free (do not pry hard on aluminum lines).
• Immediately install line caps/plugs assortment on the open lines and compressor ports.
• Remove and discard the old O-rings.

Step 7: Remove the A/C compressor mounting bolts

• Support the compressor with one hand.
• Use External Torx sockets (E10-E14) and a ratchet (3/8") to remove the compressor mounting bolts.
• Lower and remove the compressor from below.
• Torque to factory spec (Mercedes-Benz WIS) on installation.

Step 8: Prepare the new compressor (oil + seals)

• If your new compressor is not pre-filled correctly, measure oil from the old compressor and match it with A/C compressor oil (PAG oil to Mercedes-Benz spec for R-134a).
• Lightly coat new O-rings with a thin film of A/C compressor oil (PAG oil to Mercedes-Benz spec for R-134a) (this helps sealing and prevents tearing).
• Install the new O-rings onto the refrigerant line ends.

Step 9: Install the new compressor

• Position the compressor and start all mounting bolts by hand.
• Use External Torx sockets (E10-E14) and a torque wrench (10-100 Nm) to tighten bolts.
• Torque to factory spec (Mercedes-Benz WIS).

Step 10: Reconnect the A/C lines

• Remove the caps/plugs and connect the lines straight into the compressor ports.
• Install the retaining bolts using External Torx sockets (E10-E14) or Torx sockets (T25-T45).
• Torque to factory spec (Mercedes-Benz WIS).
• Tip: If it won’t seat, don’t force it.

Step 11: Reinstall the belt

• Route the belt according to your photo.
• Use the serpentine belt tool (17mm) (specialty) to rotate the tensioner.
• Slip the belt onto the A/C compressor pulley last, then release the tensioner slowly.
• Double-check the belt ribs are seated in every pulley groove.

Step 12: Reinstall undertray and lower the vehicle

• Reinstall the splash shield using Torx sockets (T25-T45) and the trim clip removal tool.
• Lower the vehicle from the jack stands (rated 3-ton minimum) using the floor jack (rated 3-ton minimum).

Step 13: Evacuate and recharge the A/C system (by weight)

• Reconnect the A/C manifold gauge set for R-134a (specialty).
• Use the vacuum pump (specialty) to pull vacuum (typically 30–45 minutes) to remove air/moisture.
• Close valves and verify the system holds vacuum (leak check).
• Recharge using A/C refrigerant (R-134a) measured with a refrigerant scale (specialty).
• Charge to the exact amount listed on the underhood label.

Step 14: Restore power and verify operation

• Reconnect the battery negative terminal using an 8mm socket.
• Start the engine and turn A/C ON.
• Check for abnormal noise, rapid cycling, and confirm cold air at the vents.
• Use a UV leak detection light (specialty) to inspect fittings if dye is present in the system.

---

✅ After Repair

• Verify vent temperature drops and stays stable at idle.
• Confirm compressor engages smoothly and no belt squeal is present.
• Inspect for oily residue around the compressor fittings (sign of a leak).
• If the A/C was open to air for an extended time, replacing the receiver/drier (or desiccant element) helps reliability.

---

💰 DIY vs Shop Cost

Shop Cost: $1,200-$2,500 (parts + labor)

DIY Cost: $450-$1,200 (parts only, assuming you have access to A/C equipment)

You Save: $750-$1,300 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 3-6 hours.

---

🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.