🔧 Wrangler - Serpentine (Accessory Drive) Belt Replacement

Your Wrangler’s 3.8L V6 does not use a timing belt—it uses an internal timing chain. If what you’re trying to replace is the belt you can see at the front of the engine that drives the alternator/power steering/A/C, that’s the serpentine belt.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Work on a cool engine; keep hands clear of the fan and pulleys.
• ⚠️ Remove the key and keep it in your pocket so nobody starts it.
• ⚠️ Don’t put fingers between the belt and pulleys while releasing tension.
• Battery disconnect is not required, but avoid shorting the alternator wiring.

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🔧 Required Tools

You'll need the following tools for this repair:

• 15mm socket
• 3/8" drive ratchet
• 3/8" drive breaker bar (18")
• Flashlight
• Work gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Serpentine belt (accessory drive belt) - Qty: 1

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📋 Before You Begin

• Park on level ground, transmission in neutral, and set the parking brake.
• Open the hood and locate the belt routing diagram (usually on the radiator support/underside of hood). If it’s missing, take a clear photo of the belt path before removal.
• A belt tensioner is a spring-loaded arm that keeps the belt tight automatically.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Locate the belt tensioner

• Use a flashlight to find the tensioner pulley (a smooth pulley on a spring-loaded arm).
• Find the tensioner’s hex boss for a tool—on the 3.8L it’s typically a 15mm.

Step 2: Relieve belt tension

• Install the 15mm socket on a 3/8" ratchet or 3/8" breaker bar.
• Rotate the tensioner to relieve tension (it will feel stiff because it’s spring-loaded).
• Move slowly; keep knuckles clear.

Step 3: Remove the old belt

• While holding the tensioner rotated with the breaker bar, slip the belt off the easiest-to-reach top pulley.
• Slowly release the tensioner back to its resting position.
• Remove the belt from the remaining pulleys by hand.

Step 4: Quick inspection (recommended)

• Spin each pulley by hand (idler, tensioner, alternator). They should spin smoothly and quietly.
• Check the tensioner pulley for wobble. If it wobbles or feels rough, plan to replace the tensioner assembly.

Step 5: Route the new belt

• Compare the new belt to the old belt for length and rib count.
• Route the belt exactly like the diagram, leaving one easy-to-reach pulley for last.
• Make sure the belt ribs sit fully in the grooved pulleys (no ribs hanging off).

Step 6: Re-apply tension and seat the belt

• Rotate the tensioner again using the 15mm socket and breaker bar.
• Slip the belt onto the last pulley, then slowly release the tensioner.
• Double-check every pulley groove with the flashlight.

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✅ After Repair

• Start the engine and watch the belt for 10–15 seconds. It should run centered with no flapping.
• Turn the steering wheel and switch the A/C on to confirm no squeal/slip.
• If you hear chirping/squealing, shut it off and re-check belt routing and seating.

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💰 DIY vs Shop Cost

Shop Cost: $120-$220 (parts + labor)

DIY Cost: $25-$60 (parts only)

You Save: $95-$160 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.

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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.

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Quick question (so I guide you correctly): Did you mean the serpentine/accessory belt (the visible belt), or are you asking about the internal timing chain job?