🔧 GLC - Engine Oil & Oil Filter Replacement

Changing the engine oil and filter keeps your turbo engine lubricated and helps prevent sludge and timing/chain wear. On your GLC, the oil filter is a cartridge style in a top-mounted housing, but the drain plug is underneath behind the lower belly pan.

Difficulty Level: Beginner | Estimated Time: 1.0–2.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool-to-warm engine, not hot; hot oil burns fast.
• ⚠️ Support the GLC with jack stands before going underneath; never trust a jack alone.
• ⚠️ Keep oil off the serpentine belt and exhaust; it can smoke and smell.
• ⚠️ Wear nitrile gloves and safety glasses; oil drips happen.
• 🔋 Battery disconnect is not required for an oil change.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Drain pan (at least 10-quart)
• Funnel
• Shop towels
• Torque wrench (10–60 Nm range)
• Ratchet (3/8")
• Socket set (8mm, 10mm, 13mm)
• Torx bit set (T25, T30)
• 27mm socket
• Trim clip remover

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Engine oil (MB-Approval 229.5, 0W-40 or 5W-40 full synthetic) - Qty: 7 quarts
• Oil filter cartridge kit (includes new O-rings) - Qty: 1
• Oil drain plug crush washer - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and place wheel chocks behind the rear tires.
• Warm the engine 3–5 minutes, then shut it off. Warm oil drains faster.
• Open the hood and remove the oil fill cap to help the crankcase vent while draining.
• Lay cardboard under the engine area.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Lift and safely support the front

• Use a floor jack (rated 3-ton minimum) at the correct front jack point and lift the front.
• Place jack stands (rated 3-ton minimum) under the front support points and lower the GLC onto them.
• Shake the vehicle gently to confirm it’s stable before going underneath.

Step 2: Remove the lower belly pan (undertray)

• Use a Torx T25 bit or Torx T30 bit (varies by fastener) to remove the undertray screws.
• If your tray uses clips, release them with a trim clip remover.
• Set the undertray and fasteners aside in a small pile so nothing gets lost.

Step 3: Drain the old engine oil

• Place the drain pan (at least 10-quart) under the oil pan drain plug.
• Use a 13mm socket with a ratchet (3/8") to loosen and remove the drain plug.
• Let the oil drain until it slows to an occasional drip (usually 10–15 minutes).

Step 4: Reinstall the drain plug with a new crush washer

• Remove the old washer and install the new oil drain plug crush washer on the drain plug.
• Thread the plug in by hand first to avoid cross-threading (damaging threads).
• Use a torque wrench (10–60 Nm range) and 13mm socket to tighten: Torque to 30 Nm (22 ft-lbs).
• If it won’t hand-thread, stop and realign.

Step 5: Replace the oil filter cartridge (top-mounted)

• From the top of the engine, place shop towels around the filter housing to catch drips.
• Use a 27mm socket with a ratchet (3/8") to loosen the oil filter housing cap.
• Pull the cap up; the filter cartridge usually comes out with it.
• Remove the old filter from the cap (it pulls off).
• Replace the O-ring(s) from the filter kit:
  • Use a trim clip remover carefully to lift the old O-ring off.
  • Install the new O-ring in the same groove (don’t twist it).
  • Wipe a thin film of fresh oil on the new O-ring using a shop towel. This helps it seal.
• Push the new filter cartridge onto the cap until it seats firmly.
• Thread the housing cap back in by hand, then tighten with a torque wrench (10–60 Nm range) and 27mm socket: Torque to 25 Nm (18 ft-lbs).
• Hand-thread first to protect plastic threads.

Step 6: Reinstall the undertray

• Position the undertray back in place.
• Install screws using a Torx T25 bit or Torx T30 bit and snug them evenly.

Step 7: Refill with the correct oil

• Lower the GLC off the jack stands (rated 3-ton minimum) using the floor jack (rated 3-ton minimum).
• Insert a funnel into the oil fill hole.
• Add 6.5 quarts of engine oil (MB-Approval 229.5, 0W-40 or 5W-40 full synthetic) first.
• Reinstall the oil fill cap.
• Start low; topping off is easier than draining.

Step 8: Start, leak-check, then set the oil level

• Start the engine and let it idle 30–60 seconds.
• Shut it off and wait 5 minutes for oil to drain back into the pan.
• Check underneath for leaks at the drain plug and around the filter housing.
• Check the electronic oil level in the instrument cluster:
  • Use steering wheel buttons to open Service menu and select Engine oil level (wording varies).
  • Add oil in small amounts (about 0.25 quart at a time) using the funnel until it reads correct.

Step 9: Reset the oil/service reminder (if due)

• With ignition on (engine off), use steering wheel controls to navigate the cluster menus.
• Try Path A: Home > Service > ASSYST PLUS > Full Service > Confirm Service.
• If you don’t see that, try Path B: Service > ASSYST PLUS > Oil change > Confirm.
• Follow the on-screen prompts to confirm.

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✅ After Repair

• Recheck for drips after your first short drive (5–10 minutes).
• Verify the oil level again in the cluster after the engine is fully warmed, then wait 5 minutes.
• Dispose of used oil and the filter properly (most parts stores accept used oil).
• Write the mileage/date on a note in the glovebox.

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💰 DIY vs Shop Cost

Shop Cost: $180–$350 (parts + labor)

DIY Cost: $60–$110 (parts only)

You Save: $120–$240 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.0–1.5 hours.

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🎯 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.

Assumption: Oil drain plug is the standard 13mm hex with undertray access; menu wording may vary slightly by cluster software.