How to Replace the Serpentine Belt on a 2018 GMC Sierra 1500 (Step-by-Step Guide)
Tools, belt routing tips, tensioner steps, safety checks, and post-install inspection to prevent squeal for 2014, 2015, 2016, 2017, 2018
How to Replace the Serpentine Belt on a 2018 GMC Sierra 1500 (Step-by-Step Guide)
Tools, belt routing tips, tensioner steps, safety checks, and post-install inspection to prevent squeal for 2014, 2015, 2016, 2017, 2018
🔧 Sierra 1500 - Serpentine Belt Replacement
The serpentine belt drives key accessories like the alternator, A/C compressor, and water pump. Replacing it is mostly about safely relieving the belt tensioner, slipping the old belt off, and routing the new belt correctly.
Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours
⚠️ Safety & Precautions
- 🧤 Work on a cool engine; hot pulleys and the fan area can burn you.
- 🛑 Keep fingers/clothing clear of pulleys at all times.
- 🔌 Do not start the engine until all tools are removed from the belt area.
- 🔋 Battery disconnect is not required, but keep the key away from the truck so no one can crank it.
🔧 Required Tools
You'll need the following tools for this repair:
- 3/8" drive breaker bar
- 3/8" drive ratchet
- 15mm socket
- Flashlight
- Trim clip tool
- Nitrile gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Serpentine belt - Qty: 1
📋 Before You Begin
- Park your Sierra 1500 on level ground and shift to Park.
- Open the hood and use a flashlight to find the belt routing diagram (usually on the fan shroud or underhood label).
- If the routing label is missing, take a clear photo of the current belt path before removal.
- Tip: Draw a quick sketch as backup.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Make room (if needed)
- If an air intake snorkel/cover blocks access, release any push-clips using a trim clip tool.
- Loosen any hose clamp (if equipped) using a 3/8" drive ratchet with the correct socket/bit on the clamp, then move the snorkel aside.
Step 2: Locate the belt tensioner
- Use a flashlight to find the belt tensioner (the spring-loaded arm with a pulley). The “tensioner” is the part that keeps the belt tight automatically.
- Identify the tensioner’s tool points:
- Use a 15mm socket on the tensioner bolt head, or use the 3/8" drive breaker bar in the square drive hole (if your tensioner has it).
Step 3: Relieve tension and remove the old belt
- Install the 15mm socket on a 3/8" drive breaker bar (or use the 3/8" drive breaker bar directly in the square hole).
- Rotate the tensioner to relieve belt tension, then slide the belt off the nearest easy-to-reach smooth pulley.
- Slowly let the tensioner return to rest. Do not let it snap back.
- Remove the belt from the remaining pulleys by hand.
Step 4: Inspect pulleys before installing the new belt
- Spin each pulley by hand and feel for roughness or wobble.
- Check the tensioner pulley and idler pulley surfaces for cracks or missing chunks.
- Tip: A noisy pulley can ruin a new belt.
Step 5: Route the new belt
- Match the new belt to the old belt length and rib count before installation.
- Route the belt exactly like the underhood routing diagram.
- Make sure the ribbed side of the belt sits fully in the grooves of every ribbed pulley.
- Leave the easiest pulley for last (often an upper smooth idler pulley).
Step 6: Apply tension and seat the belt
- Use the 15mm socket and 3/8" drive breaker bar to rotate the tensioner again.
- Slip the belt over the last pulley, then slowly release the tensioner.
- Use a flashlight to check every pulley: the belt must be centered and fully seated.
Step 7: Reinstall anything you removed
- Reinstall any snorkel/cover and clips using a trim clip tool.
- Re-tighten any loosened clamp using a 3/8" drive ratchet.
✅ After Repair
- Start your Sierra 1500 and let it idle while you watch the belt for 30-60 seconds.
- Listen for chirping/squealing; if you hear it, shut off and re-check belt seating on every pulley.
- Turn A/C on and headlights on briefly to load the belt system, then re-check for noise.
- After a short test drive, do a final quick visual check with a flashlight.
💰 DIY vs Shop Cost
Shop Cost: ₹4,500-₹9,000 (parts + labor)
DIY Cost: ₹1,500-₹3,500 (parts only)
You Save: ₹3,000-₹5,500 by doing it yourself!
Shop labor rates vary but typically run ₹1,500-₹3,000/hour. This repair takes a shop approximately 0.5-1.0 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.


















