How to Replace Ignition Coils on a 2018 GMC Acadia (Front & Rear Bank)
Step-by-step coil swap with tools/parts list, intake manifold removal tips, and 89 in-lb torque specs for 2017, 2018, 2019, 2020, 2021, 2022
How to Replace Ignition Coils on a 2018 GMC Acadia (Front & Rear Bank)
Step-by-step coil swap with tools/parts list, intake manifold removal tips, and 89 in-lb torque specs for 2017, 2018, 2019, 2020, 2021, 2022
🔧 Acadia - Ignition Coil Replacement
Your Acadia uses one ignition coil per cylinder (6 total). A bad coil can cause misfires, rough running, and a flashing check-engine light. The front bank is easy to access; the rear bank usually requires removing the upper intake manifold to reach the coils.
Difficulty Level: Intermediate | Estimated Time: 1.5-3.0 hours
⚠️ Safety & Precautions
- ⚠️ Let the engine cool fully before starting; coils sit near hot engine parts.
- ⚠️ Disconnect the negative battery cable to prevent accidental shorts.
- ⚠️ Keep dirt out of the intake ports; cover openings with clean shop towels.
- ⚠️ If the check-engine light is flashing, avoid driving until repaired (can damage the catalytic converter).
🔧 Required Tools
You'll need the following tools for this repair:
- 10mm socket
- 8mm socket
- 1/4" drive ratchet
- 3/8" drive ratchet
- 3" extension
- 6" extension
- Torque wrench (in-lb)
- Torque wrench (ft-lb)
- Flat-blade screwdriver
- Trim removal tool
- Needle-nose pliers
- Pick tool
- Shop towels
- Nitrile gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Ignition coil - Qty: 1-6
- Upper intake manifold gasket set - Qty: 1
- Dielectric grease - Qty: 1
📋 Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Open the hood and remove the engine cover (it pulls up from rubber grommets).
- Disconnect the negative battery cable using a 10mm socket and tuck it aside so it can’t spring back.
- Dielectric grease is a non-conductive grease that helps prevent moisture/corrosion.
- A torque wrench is a tool that tightens bolts to an exact spec.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Remove the engine cover
- Grip the cover firmly and pull straight upward to pop it off the mounting grommets.
Step 2: Identify which coils you’re replacing
- The front bank (closest to radiator) is easy to reach.
- The rear bank (closest to firewall) is typically under the upper intake manifold.
- If doing one coil, do that cylinder only.
Step 3: Remove a front-bank ignition coil (repeat per coil)
- Press the electrical connector lock and unplug the coil connector by hand; use a pick tool gently if the lock is stuck.
- Remove the coil hold-down bolt using a 10mm socket and 1/4" drive ratchet.
- Twist the coil slightly, then pull it straight up to remove it from the spark plug.
- Apply a tiny amount of dielectric grease inside the rubber boot (a thin film).
- Install the new coil by pushing it straight down until it fully seats.
- Reinstall the hold-down bolt and Torque to 89 in-lb (10 Nm) using a torque wrench (in-lb).
- Reconnect the electrical connector until it clicks.
Step 4: Access the rear-bank coils (upper intake manifold removal)
- Loosen the air intake duct clamps using an 8mm socket and move the duct out of the way.
- Disconnect any vacuum/PCV hoses attached to the upper intake using needle-nose pliers and a trim removal tool as needed.
- Unplug any electrical connectors that prevent lifting the upper intake; use a pick tool carefully on stubborn locks.
- Remove the upper intake manifold fasteners using a 10mm socket, 3/8" drive ratchet, and extensions.
- Lift the upper intake manifold off slowly.
- Immediately place shop towels over the exposed intake openings to keep anything from falling in.
Step 5: Replace the rear-bank coils (repeat per coil)
- Unplug the coil connector by hand; use a pick tool only to release the lock.
- Remove the coil bolt using a 10mm socket.
- Twist and pull the coil straight up to remove it.
- Apply a thin film of dielectric grease inside the boot.
- Install the new coil and push down until fully seated.
- Install the bolt and Torque to 89 in-lb (10 Nm) using a torque wrench (in-lb).
- Reconnect the coil connector until it clicks.
Step 6: Reinstall the upper intake manifold
- Remove the old upper intake manifold gaskets and install the new gasket set by hand.
- Remove the shop towels from the intake openings.
- Set the upper intake manifold back into place carefully.
- Install the manifold fasteners finger-tight first, then snug evenly using a 10mm socket.
- Tighten the fasteners in an even crisscross pattern and Torque to 89 in-lb (10 Nm) using a torque wrench (in-lb).
- Reconnect all vacuum/PCV hoses and electrical connectors.
- Reinstall the air intake duct and tighten clamps using an 8mm socket.
Step 7: Reconnect the battery and reinstall the engine cover
- Reconnect the negative battery cable using a 10mm socket and tighten securely.
- Push the engine cover back onto its grommets until it seats.
✅ After Repair
- Start the engine and listen for a smooth idle (no shaking).
- Make sure no warning lights are flashing and there’s no strong fuel/air leak sound (hissing).
- If you had a check-engine light for misfire, clear the code with a scan tool, or it may clear after a few drive cycles if fixed.
- Road test for 10-15 minutes and recheck that all connectors/hoses are secure.
💰 DIY vs Shop Cost
Shop Cost: $350-$900 (parts + labor)
DIY Cost: $60-$450 (parts only)
You Save: $200-$500 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-3.0 hours.
🎯 Ready to get started?
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