🔧 Altima - Alternator Replacement

The alternator charges your battery and powers the electrical system while the engine runs. On your Altima, replacement is mostly unbolt/bolt-on, but access is tight and you must remove the drive belt first.

Difficulty Level: Intermediate | Estimated Time: 2-4 hours

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⚠️ Safety & Precautions

• ⚠️ Disconnect the negative battery terminal first to prevent a short.
• ⚠️ Keep fingers/clothes away from the belt path and pulleys.
• ⚠️ Work on a cool engine; the exhaust area can burn you.
• ⚠️ If you raise the car, support it with jack stands—never rely on a jack.

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🔧 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
• 3/8" drive ratchet
• 3/8" drive torque wrench
• 6" extension (3/8" drive)
• 12" extension (3/8" drive)
• Serpentine belt tool (specialty)
• Flat trim tool
• Small pick tool
• Flashlight
• Digital multimeter

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Alternator - Qty: 1
• Serpentine drive belt - Qty: 1
• Battery terminal anti-corrosion washers - Qty: 1 set
• Dielectric grease - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and remove the engine cover if equipped (pull up firmly by hand).
• Disconnect the battery: use a 10mm socket to remove the negative (–) terminal first, then move it aside so it can’t spring back.
• Take a photo of the belt routing.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Remove the air intake ducting (for access)

• Use a flat trim tool to release any plastic clips holding the snorkel/duct.
• Use a 10mm socket to loosen the intake hose clamps as needed.
• Lift the ducting out and set it aside.

Step 2: Relieve belt tension and remove the serpentine belt

• Locate the belt tensioner (it’s the spring-loaded pulley that keeps the belt tight).
• Use a serpentine belt tool (specialty) (a long handled lever made for belt tensioners) on the tensioner hex and rotate to relieve tension.
• Slide the belt off the alternator pulley first, then remove it from the other pulleys.
• If you’re reusing the belt, keep it clean and note its direction of rotation.

Step 3: Unplug alternator electrical connectors

• Find the alternator’s small plug connector and depress the lock tab.
• If the tab is stubborn, use a small pick tool gently to lift the lock while pulling the connector straight off.
• Remove the rubber boot over the main power cable (B+).
• Use a 12mm socket to remove the B+ terminal nut, then move the cable aside.
• Torque on reassembly: Torque to 9.8 Nm (87 in-lbs)

Step 4: Remove the alternator mounting bolts

• Support the alternator with one hand so it doesn’t drop or bind.
• Use a 14mm socket with a 6" extension (3/8" drive) to remove the upper mounting bolt.
• Use a 14mm socket with a 12" extension (3/8" drive) to remove the lower mounting bolt.
• Work the alternator out of the bracket and lift it out of the engine bay.
• Wiggle; don’t force past hoses.

Step 5: Compare parts and transfer anything required

• Compare the old and new alternator: mounting ears, pulley alignment, and electrical connections.
• If your replacement alternator does not include the pulley (some do), do not swap pulleys unless your kit specifically requires it (pulley tools vary).

Step 6: Install the new alternator

• Set the alternator into place and hand-start the mounting bolts to avoid cross-threading.
• Use a 14mm socket to snug both mounting bolts evenly.
• Use a 3/8" drive torque wrench to finish tightening.
• Torque (alternator mounting bolts): Torque to 44 Nm (32 ft-lbs)

Step 7: Reconnect alternator wiring

• Install the B+ cable onto the stud and start the nut by hand.
• Use a 12mm socket to tighten the B+ nut.
• Torque: Torque to 9.8 Nm (87 in-lbs)
• Reinstall the rubber boot fully over the terminal.
• Reconnect the small alternator plug until it clicks.
• Apply a small amount of dielectric grease to the connector seal area only (not on the metal terminals).

Step 8: Reinstall the serpentine belt

• Route the belt according to your photo/belt diagram.
• Use the serpentine belt tool (specialty) to rotate the tensioner and slip the belt over the alternator pulley last.
• Visually confirm the belt ribs are seated in every pulley groove.

Step 9: Reinstall intake ducting and reconnect the battery

• Reinstall the intake ducting and clamps using a 10mm socket.
• Reconnect the battery negative (–) terminal using a 10mm socket.
• Torque (battery terminal clamp): Torque to 5 Nm (44 in-lbs)
• Install battery terminal anti-corrosion washers if you’re using them.

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✅ After Repair

• Start the engine and listen: no squeal, no grinding, no belt slap.
• Use a digital multimeter across the battery terminals: you should typically see about 13.8–14.7V with the engine running.
• Turn on headlights and rear defrost and re-check voltage; it should stay in the charging range.
• Recheck that the belt is centered on all pulleys after a short test drive.

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💰 DIY vs Shop Cost

Shop Cost: $600-$1,050 (parts + labor)

DIY Cost: $220-$520 (parts only)

You Save: $380-$530 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

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🎯 Ready to get started?

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