🔧 K900 - Serpentine Belt Replacement

The serpentine belt drives your A/C compressor, alternator, and other accessories. Replacing it restores proper charging and cooling performance and prevents a sudden breakdown if the belt cracks or snaps.

Difficulty Level: Intermediate | Estimated Time: 0.8-1.5 hours

Assumption: factory accessory drive with an automatic spring tensioner.

---

⚠️ Safety & Precautions

• ⚠️ Work on a cool engine; keep hands away from fans and pulleys.
• ⚠️ Keep fingers clear of the tensioner while releasing tension (it snaps back hard).
• ⚠️ Support the car securely if you raise it; never rely on a jack alone.
• ⚠️ Battery disconnect is not required, but remove the key and keep the car OFF.

---

🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Mechanic gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• 10mm socket
• 12mm socket
• 14mm socket
• 17mm socket
• 3/8" drive ratchet
• 3/8" drive breaker bar
• Torque wrench (10-150 ft-lbs)
• Flat trim clip tool
• Flashlight

---

🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Serpentine belt - Qty: 1
• Underbody splash shield clips - Qty: 1 set
• Belt tensioner assembly - Qty: 1 (optional, if noisy/weak)
• Idler pulley - Qty: 1 (optional, if noisy/rough)

---

📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Chock the rear wheels using wheel chocks.
• Open the hood and remove the plastic engine cover (usually retained by push-in grommets; pull straight up by hand).
• Find the belt routing diagram (often on a sticker in the engine bay). If it’s missing, take a clear photo of the current routing before removal.

---

🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Get access to the front of the engine

• Use a flashlight to locate the serpentine belt and all pulleys at the front of the engine.
• If access is tight from above, raise the front of the car with a floor jack (rated 3-ton minimum) and support it with jack stands (rated 3-ton minimum).
• Remove the lower splash shield (if equipped): use a flat trim clip tool for plastic clips and a 10mm socket for small bolts.

Step 2: Identify the belt tensioner

• Locate the automatic belt tensioner (a spring-loaded arm with a pulley).
• Look for the hex boss/bolt head used to rotate it (commonly fits a 14mm socket or 17mm socket).
• The tensioner is the “spring arm” that moves.

Step 3: Release belt tension

• Install a 14mm socket (or 17mm socket if that fits) on the tensioner hex, then attach a 3/8" drive breaker bar.
• Rotate the tensioner slowly to relieve tension (you’ll feel the spring load).
• While holding the tensioner rotated, slide the belt off the nearest easy pulley (usually the smooth idler pulley) by hand.
• Carefully let the tensioner return to its resting position—do not let it snap back.

Step 4: Remove the old belt

• Pull the belt out from around the remaining pulleys and remove it from the engine bay.
• Compare the old and new belts side-by-side (same length and rib count).

Step 5: Inspect pulleys and tensioner (quick check)

• Spin each pulley by hand. It should rotate smoothly and quietly (no grinding, wobble, or looseness).
• Check the tensioner pulley for roughness and the tensioner arm for weak/jerky movement.
• If a pulley is noisy, replace it now.

Step 6: Route the new belt

• Route the new belt following the under-hood routing diagram (or your photo).
• Make sure ribbed belt sections sit on ribbed pulleys, and the smooth belt back rides on smooth pulleys.
• Leave the belt off one easy-to-reach pulley for last (commonly a smooth idler pulley).

Step 7: Re-apply tension and seat the belt

• Use the 3/8" drive breaker bar with the correct 14mm socket or 17mm socket to rotate the tensioner again.
• Slip the belt onto the last pulley, then slowly release the tensioner back into place.
• Use a flashlight to confirm the belt ribs are fully seated in every grooved pulley.

Step 8: Reinstall covers and shields

• Reinstall the splash shield using a 10mm socket and a flat trim clip tool for clips.
• Lower the car from the jack stands (rated 3-ton minimum) using the floor jack (rated 3-ton minimum).
• Reinstall the engine cover by pressing it back onto its grommets.

---

✅ After Repair

• Start the engine and watch the belt for 20–30 seconds. It should run straight with no wobble.
• Listen for squealing or chirping. If you hear noise, shut the engine off and re-check belt routing and seating.
• Turn A/C on and headlights on to load the belt system; confirm no slipping noises.
• Recheck the splash shield fasteners after your first short drive.

---

💰 DIY vs Shop Cost

Shop Cost: $180-$350 (parts + labor)

DIY Cost: $35-$90 (parts only)

You Save: $145-$260 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.5 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.