How to Replace the Alternator on a 2013-2018 Nissan Altima | O'Reilly Auto Parts | O'Reill

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Your Nissan Altima’s alternator helps keep your vehicle running by charging the battery and powering electrical accessories and ignition or engine management system when the engine is on. If the alternator fails, your Nissan’s electrical systems will rely solely on the battery’s reserve capacity until it is depleted, potentially causing the engine to stall and leaving your vehicle inoperable. A damaged alternator can also overcharge, damaging the battery and other electrical components. Though jump-starting your car might help temporarily, replacing a failing alternator promptly will help keep your Altima's electrical systems functioning reliably.

Tools & Materials List

Step-by-Step Instructions

Before You Begin Your Replacement

Removing the Wheel Well Cover

Removing Your Altima’s Old Alternator

Installing Your New Alternator

Reinstalling Your Alternator Pulley Belt

Reinstalling the Wheel Panel and Cover

Final Tutorial Steps

Additional Resources

Your Nissan Altima’s alternator helps keep your vehicle running by charging the battery and powering electrical accessories and ignition or engine management system when the engine is on. If the alternator fails, your Nissan’s electrical systems will rely solely on the battery’s reserve capacity until it is depleted, potentially causing the engine to stall and leaving your vehicle inoperable. A damaged alternator can also overcharge, damaging the battery and other electrical components. Though jump-starting your car might help temporarily, replacing a failing alternator promptly will help keep your Altima's electrical systems functioning reliably.

Signs of a bad alternator include:

Weakened electrical accessories
Dim headlights or lights that become brighter with an increase in engine speed
Squeaking noises coming from the alternator pulley
A battery that won’t stay charged
A battery that smells of sulfur

Learn how to replace your Nissan Altima’s alternator with confidence with the parts, tools, and information you need from O’Reilly Auto Parts.

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Our expert lifts the hood of a parked Nissan Altima and detaches the negative battery cable.

Step 1: Prepare Your Altima

Park on a level surface and open the hood. Use your ratchet and a 10mm socket to loosen and detach the negative battery cable.

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The engine cover bolts are removed using a socket wrench.

Step 2: Remove Your Engine Cover

Use a 5mm hex bit socket, and possibly an extension, to remove the three bolts securing the engine cover.

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The engine cover is lifted off of the engine.

Grip the cover by its outside edges closest to the windshield and pull straight up on it to disengage the tab at the top then remove the cover.

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Our expert moves the boot that covers the positive cable mounting nut and removes the bolt with a socket.

Step 3: Disconnect the Positive Cable

Locate your alternator, which is toward the front of the engine bay on the passenger side, and move aside the boot covering the positive cable mounting nut. Use your ratchet and 12mm socket with extension to remove the nut.

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In two images, the wheel cover is removed and a breaker bar is used to loosen the bolts securing the front passenger wheel to the vehicle.

Step 4: Remove the Wheel Cover

Remove the wheel cover from the front passenger-side wheel by pulling directly out on it. Use a breaker bar and 21mm socket to loosen the lug nuts on that wheel.

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Our expert chocks the Altima’s back wheels and lifts the front end of the vehicle.

Step 5: Lift Your Altima

Chock the rear wheels then lift and support the front passenger side of the car.

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With the front end lifted, our expert can remove the bolts from front passenger wheel by hand.

Step 6: Remove Your Wheel Bolts

Remove the front passenger-side wheel from the vehicle. In the wheel well, you’ll see a panel that’s held in place by plastic push-clips.

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Our expert uses a trim tool to disengage the wheel panel clips.

Use a trim tool or flathead screwdriver to pop out the center of each clip to disengage and remove them. Once the clips are removed, you can also remove the panel and set it aside.

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The wheel panel is removed, allowing a view of the serpentine belt and tensioner.

Step 7: Remove the Wheel Panel

With the panel removed, you’ll have a view of the serpentine belt and tensioner. Use a ratchet and 17mm socket to rotate the tensioner clockwise and slip the belt off the nearest pulley.

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In three images, the the alternator pulley belt is removed and a socket loosens the bolts securing the alternator.

Step 8: Remove Your Old Alternator

Back in the engine bay, slip the belt off the alternator pulley and remove it. Use your ratchet and 13mm socket to loosen the two alternator mounting bolts at the top and bottom. Once they’re loose, remove them the rest of the way by hand.

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The old alternator is lifted out of the Altima’s engine bay.

You can now carefully lift the old alternator up and out of the engine bay.

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The mount bolts are inspected side-by-side. Sandpaper is used to remove some slight corrosion.

Step 9: Inspect Your Mounting Bolts

Visually inspect the two mounting bolts and the ring at the end of the cable you detached earlier. Use fine-grit sandpaper to remove any corrosion if needed.

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In three images, our expert lowers the new alternator out of the Altima’s engine bay and threads the bolts by hand to make sure it’s secure to the vehicle.

Step 10: Install Your New Alternator

Lower your new alternator into position and thread the top mounting bolt by hand. Thread the bottom bolt by hand then tighten them both with your ratchet and 13mm socket.

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The mounting bolts are tightened using a torque wrench.

Once they’re snug, use a torque wrench to tighten the bolts to 18 foot-pounds.

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The positive cable boot is moved back over the bolt.

Step 11: Reinstall Your Wiring Harness and Cables

Reconnect the wiring harness, pressing it in until you hear its locking tab snap into place. Reinstall the top cable, making sure the ring is flush and thread the nut by hand until it’s snug. Use your socket to tighten the nut and secure the cable, being careful not to overtighten it. Move the boot back into place over the nut.

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The alternator pulley belt is reinstalled onto the vehicle.

Step 12: Re-Route Your Belt

Start in the engine bay and route your belt around the pulleys as best you can from the top leaving the A/C compressor pulley toward the front of the engine bay at the bottom for last.

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Our expert uses a socket to rotate the tensioner.

Back in the wheel well, route the belt around the tensioner and crankshaft pulleys. Use your 17mm socket to rotate the tensioner clockwise and slip the belt onto the A/C pulley.

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The belt is properly seated on both the alternator and A/C compressor pulleys.

Do It Right: Before releasing the tensioner, make sure the belt is routed properly around the pulleys you can see. Slowly release the tensioner then double-check the belt all the way around to make sure it’s properly seated on all the pulleys.

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The wheel panel is reinstalled.

Step 13: Reinstall Your Wheel Panel

Reinstall the panel in the wheel well with the push clips you removed, pushing in their outer edges first then pushing in the middle pin to secure them.

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Our expert replaces the front passenger wheel and tightens the nuts to secure it. The vehicle is still lifted.

Step 14: Replace and Secure Your Wheel

Put your wheel back in place then install and tighten the nuts until the wheel is flush against the hub.

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The front of the Altima is lowered and the wheel chocks are removed. A torque wrench is used to tighten the bolts.

Step 15: Lower Your Vehicle

Lower your front end and remove the wheel chocks. Use your torque wrench to tighten the lug nuts in a star pattern to 83 foot-pounds.

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Snap your wheel cover back into place, making sure the space for the valve stem in lined up and test it to make sure it’s secure.

Step 16: Replace Your Wheel Cover

Snap your wheel cover back into place, making sure the space for the valve stem in lined up and test it to make sure it’s secure.

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The Altima’s engine cover is replaced and the mounting bolts are secured.

Step 17: Replace Your Engine Cover

Back in the engine bay, align the grommet on the bottom of your engine cover with the protruding tab near the valve cover.

Once the engine cover is in place, align the mounting bolt holes and begin to thread those bolts by hand.

Use your ratchet and 5mm hex bit socket to secure the bolts.

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A socket and ratchet is used to tighten and secure the negative battery cable.

Step 18: Reconnect and Secure Your Negative Battery Cable

Reconnect your negative battery cable and use a 10mm socket and ratchet to tighten it.

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Our expert checks the belt to ensure all pulleys are operating as they should.

Step 19: Check Your Work

Start up the car and let it run for 5 to 10 seconds then turn it back off. Double-check the belt to make sure it’s still seated properly on all the pulleys. If everything looks good, close the hood.

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This guide and video walk you through the alternator replacement process for a 2014 Nissan Altima, and are also applicable to most 2013, 2015, 2016, 2017, and 2018 Nissan Altima models with a 2.5L engine. Replacing a worn or failing alternator ensures your vehicle’s electrical system works efficiently, allowing your electrical accessories, headlights, dashboard lights, and battery to perform as they should. If you’ve noticed issues like dimming lights or a battery that struggles to hold a charge, stop by your local O’Reilly Auto Parts for free alternator testing and free battery testing to help you begin your diagnosis and repairs.

The automotive repair work depicted in this series is performed under the direction of the manufacturer of the product featured. Prior to undertaking any of the demonstrated repairs on your vehicle, we suggest you consult with a certified mechanic or another professional who can adequately advise you of the proper repair or remedy required. O’Reilly Automotive Stores, Inc. and its affiliates (“O’Reilly”) disclaims any responsibility for injury or damage resulting from a viewer’s attempt to recreate the repairs shown in this series.