How to Replace the Serpentine Belt on a 2018 Toyota Tundra (Accessory Drive Belt)
Step-by-step instructions, required tools/parts, belt routing tips, and safety checks for a smooth install for 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
How to Replace the Serpentine Belt on a 2018 Toyota Tundra (Accessory Drive Belt)
Step-by-step instructions, required tools/parts, belt routing tips, and safety checks for a smooth install for 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021
🔧 Serpentine Belt - Replacement
The serpentine belt on your Tundra drives key accessories like the alternator and A/C. Replacing it is mostly about safely releasing the automatic belt tensioner (a spring-loaded pulley that keeps the belt tight) and routing the new belt correctly.
Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours
⚠️ Safety & Precautions
- ⚠️ Work on a cool engine; keep hands clear of fans and pulleys.
- ⚠️ Key out of the ignition; never work near belts with the engine running.
- ⚠️ Do not pry on pulleys with a screwdriver; it can crack ribs or bend brackets.
- 🧤 Battery disconnect is not required, but remove the key and avoid shorting tools near the battery.
🔧 Required Tools
You'll need the following tools for this repair:
- 14mm socket
- 3/8" drive ratchet
- 3/8" drive breaker bar (18" minimum)
- 3/8" drive extension set (3" and 6")
- Flashlight
- Mechanic gloves
- Safety glasses
🔩 Required Parts
HowToo sells all the parts you need for this repair:
- Serpentine belt (accessory drive belt) - Qty: 1
📋 Before You Begin
- Park on level ground and set the parking brake.
- Open the hood and use a flashlight to find the belt routing diagram (usually on the radiator support/under-hood area).
- If the routing label is missing, take a clear photo of the current belt path before removal.
🔨 Step-by-Step Instructions
Follow these steps in order:
Step 1: Verify belt routing
- Use a flashlight to confirm the belt path matches the routing label.
- Photo now saves frustration later.
Step 2: Release tension from the belt tensioner
- Install a 14mm socket on the belt tensioner arm bolt.
- Use a 3/8" drive breaker bar (18" minimum) to rotate the tensioner to relieve belt tension (it will feel spring-loaded).
- While holding the tensioner released, slide the belt off one easy-to-reach smooth pulley (often the idler pulley) by hand.
- Slowly let the tensioner return to its resting position. Don’t let it snap back.
Step 3: Remove the old belt
- Remove the belt from the remaining pulleys by hand.
- Use a flashlight to inspect each pulley surface for rust, wobble, or damaged edges.
Step 4: Route the new belt
- Match the new belt to the old belt length and rib count before installing.
- Route the new belt around the pulleys following the routing label/photo, leaving one easiest pulley for last.
- Make sure the belt ribs sit fully inside the grooved pulleys (no ribs hanging off the edge).
- Misalignment can shred a new belt fast.
Step 5: Re-apply tension and seat the belt
- Use the 14mm socket and 3/8" drive breaker bar (18" minimum) to rotate the tensioner again.
- Slip the belt onto the last pulley, then slowly release the tensioner.
- Use a flashlight to double-check belt alignment on every pulley.
✅ After Repair
- Start the engine and let it idle for 20-30 seconds while you watch the belt track on the pulleys.
- Turn the A/C on and off and listen for squeal or chirping.
- Shut the engine off and re-check that the belt is still centered on every pulley.
💰 DIY vs Shop Cost
Shop Cost: $150-$300 (parts + labor)
DIY Cost: $25-$70 (parts only)
You Save: $80-$230 by doing it yourself!
Shop labor rates vary but typically run $100-$150/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.

















