How to Replace the Serpentine Belt on a 2018 GMC Terrain (Step-by-Step Guide)
Tools, parts list, belt routing tips, wheel-well access steps, and post-install checks to stop squeal for 2018, 2019, 2020
How to Replace the Serpentine Belt on a 2018 GMC Terrain (Step-by-Step Guide)
Tools, parts list, belt routing tips, wheel-well access steps, and post-install checks to stop squeal for 2018, 2019, 2020
đź”§ Terrain - Serpentine Belt Replacement
The serpentine belt drives key accessories like the alternator and A/C. Replacing it is mostly about safely relieving belt tension, routing the new belt correctly, and making sure it’s seated in every pulley groove.
Difficulty Level: Intermediate | Estimated Time: 0.8-1.5 hours
⚠️ Safety & Precautions
- ⚠️ Keep hands and tools away from the belt path with the engine running.
- ⚠️ Let the engine cool; the belt area is near hot components.
- ⚠️ Support the vehicle with jack stands if you remove the right-front wheel.
- ⚠️ Do not pry on pulleys; use the tensioner only.
- Battery disconnect is not required, but keep the key away from the vehicle so it can’t remote-start.
đź”§ Required Tools
You'll need the following tools for this repair:
- Safety glasses
- Nitrile gloves
- Wheel chocks
- Floor jack (rated 3-ton minimum)
- Jack stands (rated 3-ton minimum)
- Breaker bar 3/8" drive
- 15mm socket 3/8" drive
- Ratchet 1/4" drive
- 7mm socket 1/4" drive
- 10mm socket 1/4" drive
- Trim clip removal tool
- Lug wrench 19mm
- Flashlight
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Serpentine belt - Qty: 1
- Fender liner push clips - Qty: 2-6
đź“‹ Before You Begin
- Park on level ground, shift to Park, and set the parking brake.
- Place wheel chocks behind the rear wheels.
- Open the hood and find the belt routing diagram (usually a sticker on the radiator support/upper shroud). If it’s missing, take a clear photo of the current routing before removal.
- If access is tight from above, plan to remove the right-front wheel and inner fender liner for easier access.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Create access to the belt area
- Open the hood and remove the engine cover by pulling it straight up by hand (it’s held by rubber grommets).
- If needed, remove the intake duct resonator area for room: use a 7mm socket 1/4" drive to loosen hose clamps, and use a 10mm socket 1/4" drive to remove any retaining bolts.
- Take a quick “before” photo for routing.
Step 2: Lift the right-front corner (recommended for easiest access)
- Use wheel chocks at the rear wheels.
- Loosen the right-front lug nuts slightly using a lug wrench 19mm.
- Lift the right-front using a floor jack (rated 3-ton minimum) and support it with jack stands (rated 3-ton minimum).
- Remove the wheel using the lug wrench 19mm.
Step 3: Remove the right inner fender liner (splash shield)
- Use a trim clip removal tool to pop out the plastic push clips.
- Use a 7mm socket 1/4" drive and 10mm socket 1/4" drive to remove the small screws/bolts holding the liner.
- Pull the liner back enough to clearly see the belt, tensioner, and crank pulley.
- Keep clips in a cup so none get lost.
Step 4: Relieve belt tension
- Locate the belt tensioner (spring-loaded arm with a pulley). The tensioner is what keeps the belt tight automatically.
- Install a 15mm socket 3/8" drive on the tensioner’s hex and attach a breaker bar 3/8" drive.
- Rotate the tensioner smoothly to relieve tension, then slide the belt off one easy-to-reach pulley (usually the alternator pulley) with your free hand.
- Slowly let the tensioner return to its resting position. Do not let it snap back.
Step 5: Remove the old belt and compare it
- Pull the belt out through the wheel well opening.
- Compare the old and new belts side-by-side (length and rib count should match).
- Use a flashlight to check pulleys for wobble, heavy rust, or damaged grooves.
Step 6: Route the new belt
- Route the new belt following the under-hood belt diagram.
- Make sure the ribbed side of the belt sits in the grooved pulleys, and the smooth side rides on smooth pulleys.
- Leave one upper pulley for last (the easiest “last pulley” to slip on).
- If it won’t slip on, re-check routing.
Step 7: Apply tension and seat the belt
- Use the 15mm socket 3/8" drive with the breaker bar 3/8" drive to rotate the tensioner again.
- Slip the belt fully onto the last pulley, then slowly release the tensioner.
- Verify the belt is fully seated in every pulley groove by sight and touch (carefully).
Step 8: Reinstall the fender liner and wheel
- Reinstall the inner fender liner using the 7mm socket 1/4" drive, 10mm socket 1/4" drive, and trim clip removal tool (to reinstall push clips).
- Reinstall the wheel and snug lug nuts using the lug wrench 19mm.
- Lower the vehicle from the jack stands (rated 3-ton minimum) using the floor jack (rated 3-ton minimum).
- Tighten lug nuts in a star pattern: Torque to 140 Nm (103 ft-lbs) using a lug wrench 19mm (torque wrench recommended if available).
Step 9: Reinstall any intake parts and the engine cover
- Reinstall intake ducting using a 7mm socket 1/4" drive and 10mm socket 1/4" drive as applicable.
- Press the engine cover back onto its grommets by hand.
âś… After Repair
- Start your Terrain and let it idle while you watch the belt for 30-60 seconds (stand clear of moving parts).
- Listen for chirping/squealing; if you hear it, shut the engine off and re-check belt routing and seating.
- Recheck that the inner fender liner is secured and not rubbing the belt area.
đź’° DIY vs Shop Cost
Shop Cost: $160-$320 (parts + labor)
DIY Cost: $35-$85 (parts only)
You Save: $125-$235 by doing it yourself!
Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 hours.
🎯 Ready to get started?
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