🔧 Altima - Serpentine Belt Replacement

This is an intermediate job, mainly because access is tight. The belt is released with the automatic tensioner, then removed through the lower passenger-side area. Nissan identifies the drive-belt location on the passenger side of the KR20DDET engine. nissanusa.com

Difficulty Level: Intermediate | Estimated Time: 1-2 hours

Assumption: These steps cover belt replacement only, with the original tensioner and pulleys remaining installed.

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⚠️ Safety & Precautions

• ⚠️ Work only with the engine completely cold.
• ⚠️ Keep your fingers out of the belt path while moving the spring-loaded tensioner.
• ⚠️ Never allow the tensioner to snap back. Release it slowly.
• ⚠️ Support the Altima with jack stands. Never work beneath a vehicle supported only by a jack.
• ⚠️ Disconnect the negative battery terminal so the engine cannot be started accidentally.
• ⚠️ Do not put belt dressing, oil, grease, or coolant on the new belt.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 3/8-inch drive ratchet
• 3/8-inch drive serpentine belt tool (specialty)
• Plastic trim-clip removal tool
• Low-profile floor jack rated 2 tons minimum
• Jack stands rated 2 tons minimum
• Wheel chocks
• LED work light
• Mechanic gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Six-rib serpentine belt - Qty: 1
• Lower splash-shield clips - Qty: As needed

The matching belt aisle is open beside this guide. Two compatible belt choices are currently listed from approximately $17-$26.

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📋 Before You Begin

• Park on firm, level ground and select Park.
• Apply the parking brake and place wheel chocks behind both rear tires.
• Open the hood and let the engine cool fully.
• Take a clear picture of the existing belt routing before touching the tensioner.
• Compare the new belt with the old one. The rib count and overall length should match closely.
• No infotainment service mode or scan tool is required for this repair.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Disconnect the battery

• Use the 10mm socket and 3/8-inch drive ratchet to loosen the negative battery-terminal nut.
• Lift the negative terminal from the battery and position it where it cannot spring back onto the post.

Step 2: Raise and support the passenger side

• Use the low-profile floor jack at the approved front lifting point.
• Place a jack stand beneath the reinforced support point and lower the vehicle onto it.
• Give the vehicle a gentle push before getting underneath. It must remain completely stable.

Step 3: Remove the lower splash shield

• Use the 10mm socket and 3/8-inch drive ratchet to remove the shield bolts.
• Use the plastic trim-clip removal tool to lift the center pins, then remove the plastic clips.
• Lower the shield carefully and organize the fasteners by location.
• Plastic clips prefer patience over horsepower.

Step 4: Record the belt routing

• Use the LED work light to identify every pulley and the automatic tensioner.
• Confirm your routing picture clearly shows which pulleys use the ribbed side and which use the smooth back of the belt.
• If the old belt has already broken, follow the routing diagram provided with the matched belt listing rather than guessing.

Step 5: Release the automatic tensioner

• Fit the 3/8-inch drive serpentine belt tool securely into the tensioner drive point.
• Rotate the tool slowly against spring pressure until the belt becomes loose.
• Keep the tool square to the tensioner. Stop if it slips or begins rounding the engagement point.

Step 6: Remove the old belt

• While holding the tensioner released with the serpentine belt tool, slide the belt from the easiest accessible smooth pulley.
• Slowly return the tensioner to its resting position.
• Remove the belt from the remaining pulleys and guide it out through the lower opening.

Step 7: Inspect the tensioner and pulleys

• Use your gloved hand to rotate each accessible idler pulley.
• Replace any pulley that feels rough, binds, wobbles, or makes a dry grinding noise.
• Inspect the tensioner for leakage, looseness, or sideways pulley movement.
• Check for oil or coolant contamination. Repair the leak before installing the new belt.

Step 8: Route the new belt

• Route the new belt around every pulley except the easiest accessible smooth pulley.
• Keep the ribbed side seated in the grooves of each grooved pulley.
• Keep the smooth back of the belt against smooth pulleys.
• Leave a little slack near the final pulley, but do not twist the belt.

Step 9: Install the belt over the final pulley

• Use the 3/8-inch drive serpentine belt tool to rotate the tensioner fully.
• Slide the belt over the final smooth pulley.
• Slowly release the tensioner until it loads the belt.
• Remove the tool only after the tensioner has stopped moving.

Step 10: Verify every pulley

• Use the LED work light to inspect the entire visible belt path.
• Confirm every rib is inside its matching pulley groove.
• Make sure the belt is centered on every smooth pulley and is not riding over an edge.
• Correct any misalignment before starting the engine. One rib hanging off is enough to shred the belt.

Step 11: Reinstall the splash shield

• Position the shield and install its clips using your hands.
• Install the bolts with the 10mm socket and 3/8-inch drive ratchet.
• Tighten the small shield bolts until snug. Do not crush the plastic or strip the retainers.

Step 12: Lower the vehicle and reconnect the battery

• Use the floor jack to raise the vehicle slightly and remove the jack stand.
• Lower the Altima completely and remove the wheel chocks.
• Reconnect the negative battery terminal using the 10mm socket and 3/8-inch drive ratchet.
• Tighten the terminal until it cannot rotate by hand. Do not overtighten it.

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✅ After Repair

• Check that all tools are clear of the engine compartment.
• Start the engine and watch the belt from a safe distance for approximately 30 seconds.
• Turn the air conditioning on and listen for chirping, slapping, or squealing.
• Shut the engine off immediately if the belt walks sideways or rides over a pulley edge.
• After the engine stops, perform one final visual check of every accessible pulley.
• If the battery disconnect resets automatic window operation, fully lower and then fully raise each affected window while holding its switch.

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💰 DIY vs Shop Cost

Shop Cost: $140-$260 (parts + labor)

DIY Cost: $17-$26 for the belt, or approximately $25-$90 if you also need a belt tool

You Save: Approximately $100-$200 by doing it yourself!

Local labor pricing varies. This repair typically takes a shop approximately 0.7-1.2 hours.

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🎯 Ready to get started?

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