How to Replace the Alternator on Chevrolet Cars

by Contributing Writer

Replacing the alternator in your Chevrolet car is a great do it yourself project that will save you money. The alternator on your Chevrolet car is responsible for charging the battery as well as generating electricity for the ignition system and other accessories in the car. If you are experiencing a weak battery on a regular basis, the alternator may be failing. Removing the alternator from the car will allow you to have it tested or replace it. You can buy a new or remanufactured alternator at most auto parts stores and most of them will bench test your old starter free if you bring it to the store.

Under The Hood:

 How to Replace the Alternator on a Chevy S10

Disconnect the negative battery terminal, and then isolate it so it does not come back into contact with the battery post during the alternator replacement.

Remove the air inlet duct, if applicable to your S-10.

Place the 3/8-inch square drive adapter into the serpentine belt tool, and insert it into the square drive on the tensioner pulley. Then pivot the tensioner to relieve the tension on the belt. Holding the tool with one hand, use your other hand to remove the belt from the alternator pulley. Do not remove the belt unless you're replacing it as well. Allow the tensioner to gently rest back into its applied position, and then remove the serpentine belt tool.

Remove the heater hose brace, if applicable to your S-10.

Locate the black- or red-colored cap cover on the back of the alternator, and pull it off with your fingers to expose the terminal retaining nut. Hold the inside nut stable with a wrench, then pull out the outer retaining nut with a ratchet and socket. Remove the terminal wire.

Pull out the two front alternator mounting bolts, then remove the rear alternator bracket bolt. Using a small pry bar, pry the alternator upward. Disconnect the remaining wire connections to the alternator, and lift it from the S-10. Use a small hammer to tap forward the spacer bushing at the front of the alternator mount, so that you can easily fit the replacement alternator into the mount.

Install the new alternator by reversing the procedure. Test-start the alternator when you have replaced the negative battery terminal. Be sure to charge the battery with a battery charger.

Items you will need

  • Ratchet and socket set

  • Hand wrench set

  • Serpentine belt tool with 3/8-inch square drive adapter

  • Small hammer

  • Small pry bar

  • Replacement alternator

  • Battery charger

 How to Replace the Alternator on a Chevrolet Lumina

Attach the serpentine belt tool to the tensioner of the belt. The tensioner is the pulley located on the front of the engine just below the power steering pump. Use the 3/8-inch square attachment or a regular 3/8-inch ratchet.

Push the tensioner towards the rear of the car to loosen the belt. When loose, remove the belt from the alternator. Do not remove the belt tool from the tensioner. Allow the tensioner to move back forward slowly. Releasing the tensioner will cause it to break.

Loosen the two bolts holding the alternator to the engine. One bolt is located at the back bottom of the alternator. The other is located at the top front of the alternator. Both of these bolts are 9/16-inch bolts and require the adjustable wrench to remove along with the socket and ratchet.

Unplug the black plug from the top back of the alternator. Remove the red wire from the back of the old alternator.

Install the red wire to the back of the new alternator and plug the black wire into the new alternator.

Position the new alternator and reinstall both retaining bolts. Make sure to tighten both bolts.

Push the belt tool back towards the back of the vehicle and loop the belt back around the new alternator. Check the belt to make sure it is properly routed around the rest of the pulleys. Gradually release the tensioner and remove the belt tool or ratchet.

Start the vehicle and make sure the battery light goes out. The car may need a jump start if the battery is dead. The car may have to run for 30 minutes before the battery light goes out.

Items you will need

  • 9/16-inch socket

  • Ratchet

  • 9/16-inch wrench

  • Serpentine belt tool

  • Adjustable wrench

 How to Replace an Alternator on a Chevy Malibu

Removing the Old Alternator

Disconnect the negative battery cable using a wrench.

Remove the coolant reservoir for better access, if necessary, using a ratchet and socket. The reservoir is the plastic container located at the front and to the right (passenger side) of the engine compartment.

Detach the belt guard from the top of the belt. if your particular Malibu model is equipped with it, using a ratchet and socket. The belt guard is located between the water pump and the power steering pump.

Rotate the belt tensioner pulley to release the belt tension. Use a long 13 mm box wrench or 3/8-inch drive breaker bar, depending on your particular model.

Slip the belt off the alternator pulley.

Remove the two top alternator mounting bolts and the front bolt if you have a 2.4L engine model. Remove the top and front mounting bolts from the alternator if you have a 3.1L engine model. Use a ratchet and socket for both model types.

Unscrew the mounting nut from the rear of the alternator if you have a 3.1L engine model. Use a ratchet with a ratchet extension, universal joint and deep well socket to reach the mounting nut.

Unplug the electrical connector from the alternator. Then detach the wire from the back of the alternator using a wrench.

Unscrew the power steering line clip using a ratchet and socket, if you have a 3.1L engine model, so that you can work the alternator out of the engine compartment.

Remove the alternator from the vehicle.

Installing the New Alternator

Set the new alternator in its mounting position in the engine compartment.

Install the power steering line clip, if you have a 3.1L engine model, using the ratchet and socket.

Plug the electrical wire harness and the single wire with the retaining nut into the back of the alternator using the wrench.

Install the mounting nut to the rear of the alternator, if you have a 3.1L engine model. Use the ratchet with the ratchet extension, universal joint and deep well socket to tighten the mounting nut.

Install the two top alternator mounting bolts and the front bolt if you have a 2.4L engine model. Install the top and front mounting bolts to the alternator if you have a 3.1L engine model. For both models, use a ratchet and socket.

Rotate the belt tensioner pulley using the long 13 mm box wrench or 3/8-inch drive breaker bar, depending on your particular model.

Slip the belt onto the alternator pulley.

Attach the belt guard to the top of the belt, if your particular Malibu model is equipped with it, using the ratchet and socket.

Install the coolant reservoir, if you had to remove it, using a ratchet and socket.

Connect the negative battery cable using the wrench.

Items you will need

  • Wrench set

  • Ratchet

  • Socket set

  • 13 mm box wrench or 3/8-inch drive breaker bar

  • Ratchet extension (optional)

  • Universal joint (optional)

  • Deep well socket (optional)

 How to Replace an Alternator in a Suburban

Disconnect the battery by unfastening the positive cable. Secure the cable away from the battery.

Disconnect the alternator's primary power output wire by turning the nut counterclockwise and pulling the wire off.

On single-belt systems, remove the belt by loosening the alternator's mount and adjustment bolts. With the adjustment bolt loose, the unit will slide in the mount's groove and release the belt tension. Remove the belt and set it aside for reuse. Slide the bolts out of the mount to free the alternator.

On serpentine systems, press the tension pulley arm firmly to loosen the belt, then slide the belt out from underneath the idle pulley wheel. Release the tension pulley arm and the belt will now have enough slack to be removed from the alternator pulley. Loosen all of the alternator's mount bolts by turning them counterclockwise, then slide the bolts out and remove the alternator.

Replace the alternator with a new unit by positioning it into the mount and sliding the mount bolts through. Finger tighten the stationary bolts. On the single belt system, wrap the belt around the alternator's pulley and pull the alternator to tighten it. Fully tighten all mount bolts, including the adjustment bolt, until they are very snug. On serpentine systems, tighten all mount bolts completely, then wrap the belt around the pulley, press the tension arm, and slide the belt underneath the idle pulley wheel. Release the tension arm and the belt will tighten.

Reattach the power output terminal to the rear of the alternator by turning the nut clockwise. Replace any black rubber insulation cap that may be present. Reconnect the battery by repositioning the cable on the terminal and turning the positive terminal bolt in a clockwise direction.

Items you will need

  • Socket set

 How to Replace the Alternator in a Geo Metro

Determine which alternator your Geo Metro will need. You'll want to be sure the new alternator is compatible with your Metro's engine. The Geo Metro has 1.0 L, 1.0 L turbocharged and 1.3 L engines.

Disconnect the negative battery cable with a socket wrench so you do not short out the alternator when you remove it. Take off the rubber cover for the B+ terminal and loosen its retaining nut with a socket wrench. Unplug the electrical connector from the alternator.

Remove the alternator drive belt and detach the adjustor bolt. Loosen the pivot bolt and hold the alternator as you remove the pivot bolt. Remove the alternator from the vehicle.

Install the new alternator and put on the pivot bolt and drive belt loosely. Install the drive belt and tighten the adjustor and pivot bolts for the drive belt to 17 foot pounds with a torque wrench.

Attach the electrical connector to the alternator and use a torque wrench to tighten the B+ terminal nut to 71 inch pounds Replace the rubber cover for the terminal. Connect the negative battery cable with a socket wrench.

Start the engine and check the operation of the charging system.

Items you will need

  • New alternator

  • Socket wrench set

  • Torque wrench

 How to Replace the Alternator in a Geo Tracker

Determine which alternator your Geo Tracker will need. You'll want to be sure the new alternator is compatible with your Tracker's engine. Models made from 1989 to 1998 have a 1.6 L engine and a 2.0 L engine was added for models made after 1998.

Disconnect the negative battery cable with a socket wrench. Label and disconnect the electrical connections to the alternator. Detach the evaporative charcoal canister and its mounting bracket with a socket wrench.

Loosen the mounting bolts with a socket wrench so that you can take the alternator drive belt off of the pulley. Hold the alternator while you remove the mounting bolts completely and take the alternator off the vehicle.

Install the new alternator assembly and tighten the mounting bolts with your fingers. Place the drive belt on the pulley and adjust the tension. Use a torque wrench to tighten the mounting bolts to 17 foot pounds.

Connect the electrical wiring to the alternator using the labels you applied earlier for guidance. Install the evaporative charcoal canister and its mounting bracket, and reconnect the negative battery cable with a socket wrench.

Items you will need

  • New alternator

  • Socket wrench set

  • Torque wrench

 How to Change an Alternator in a 2003 Chevy Malibu

Locate the negative battery cable on the negative terminal on the battery. Use a wrench to remove the retaining bolt and then remove the battery cable end from the negative terminal.

Locate the automatic belt tensioner on the front of the engine just below the alternator. Insert a 3/8-inch drive ratchet into the hole on the front of the tensioner and rotate it counterclockwise, allowing the belt to slack. Remove the belt from the alternator pulley.

Locate the three mounting bolts that secure the alternator to the mounting bracket on the engine. Remove the bolts with a socket and ratchet, then lift the alternator off the engine far enough to access the wires on the back of the alternator.

Disconnect the plug-in connector from the top of the alternator, pushing in the locking tab and then pulling the connector loose. Loosen the nut on the second connector with a wrench, then remove the nut and wire from the alternator. Remove the alternator from the engine compartment.

Position the new alternator in the engine compartment so it is sitting on the mounting bracket. Install the plug-in connector on the top of the alternator, pushing it in until it locks onto the connector. Install the large wire onto the stud terminal or “b” terminal, followed by the retaining nut. Tighten the nut with a wrench.

Install the three mounting bolts through the alternator and thread them into the mounting bracket. Tighten the bolts with a socket and ratchet, then torque the bolts to 37 pounds-feet with a torque wrench.

Slide the serpentine belt onto the alternator pulley while holding the belt tensioner off the belt. Rotate the tensioner clockwise with a 3/8-inch drive ratchet, allowing it to tighten the belt.

Install the negative battery cable on to the negative battery terminal and tighten the retaining bolt with a wrench.

Items you will need

  • Wrench set

  • 3/8-inch drive ratchet

  • Socket set

  • Torque wrench

 How to Replace the Alternator in a Chevy Impala

Determine which alternator your Chevy Impala will need. You'll want to be sure the new alternator is compatible with your Impala's engine. The first generation of the Impala covers 1958 to 1961 and these models were available with 235 cubic inch (ci), 283 ci, 348 ci and 409 ci engines. Second generation models made from 1962 to 1964 may have a 230 ci, 283 ci, 327 ci or 409 engine.

Look at later generations of the Impala. The third generation was made from 1965 to 1970 and was offered with 250 ci, 283 ci, 307 ci, 350 ci, 396 ci, 409 ci and 427 ci engines. The fourth generation Impala covers 1971 to 1976 and was available with 350 ci, 400 ci and 454 ci engines.

Check the engine sizes for more recent versions of the Impala. The fifth generation was made from 1977 to 1985 and may be equipped with 229 ci, 231 ci, 250 ci, 267 ci, 305 ci, 350 ci or a 350 diesel engine. The sixth generation of the Impala covers 1994 to 1996 and has a 5.7 L engine.

Examine the engine size for the latest models of the Chevy Impala. The seventh generation was made from 2000 to 2005 and is available with 3.4 L and 3.8 L (supercharged and non-supercharged) engines. The latest generation debuted in 2006 and may have a 3.5 L, 3.9 L or 5.3 L engine.

Drain the coolant and disconnect both battery cables and battery tray bolts with a socket wrench so you can remove the battery and its tray. Remove the drive belt, engine cooling fan, thermostat housing and radiator hose using a socket wrench.

Take off the idler pulley bolt with a socket wrench and remove the idler pulley. Loosen the positive battery to the alternator and unplug its electrical connections.

Remove the alternator mounting bolts with a socket wrench and remove the alternator.

Install the new alternator assembly and reverse the alternator removal procedure. Tighten the positive battery terminal on the alternator to 15 ft. lbs. with a torque wrench and torque the idler pulley bolt and alternator mounting bolts to 37 foot pounds. Torque the bolts for the thermostat housing to 80 inch pounds and the battery tray bolt to 44 inch pounds.

Items you will need

  • New alternator

  • Socket wrench set

  • Torque wrench

 How to Replace the Alternator in a Chevy Camaro

Determine which alternator your Chevy Camaro will need. You'll want to be sure the new alternator is compatible with your Camaro's engine. Models made from 1967 to 1969 were available in a variety of engine sizes including 3.8 L, 4.0 L, 4.9 L, 5.4 L, 5.7 L, 6.5 L, 6.6 L and 7.0 L.

Look at engine sizes for additional Camaro models. The second generation Camaro covers the years 1970 to 1981 and was offered with 3.8 L, 4.1 L, 5.7 L, 6.5 L, 6.6 L and 7.4 L engines. The third generation was made from 1982 to 1992 and came with 2.5 L, 2.8 L, 3.1 L, 5.0 L and 5.7 L engines. Models made from 1993 to 2002 had the option of a 3.3 L, 3.8 L or 5.7 L engine.

Position your vehicle over a hoist and raise it. Disconnect both battery cables with a socket wrench and remove the accessory drive belt.

Slide down the boot on the alternator to access the positive terminal stud and remove the nut on the stud with a socket wrench. You will now be able to remove the cable.

Remove the mounting bolts for the rear bracket of the alternator with a socket wrench and disconnect the cooler lines for the transmission oil. Unscrew the mounting bolts of the front of the alternator and take off the oil cooler clip. Remove the alternator from the vehicle.

Install the new alternator assembly by reversing the removal process. Tighten the mounting bolts on the front of the alternator with a torque wrench to 37 foot pounds and torque the mounting bolt on the rear bracket to 18 foot pounds. Torque the nut on the alternator stud to 16 foot pounds.

Items you will need

  • New alternator

  • Socket wrench set

  • Torque wrench

 How to Replace an Alternator on a 2000 Chevy Blazer

Pull the 2000 Chevy Blazer into a safe working area and shut off the engine. Open the hood and locate the battery on the driver side front of the engine.

Remove the negative battery cable from the battery with the adjustable wrench. Turn the negative battery cable bolt counterclockwise to loosen and remove the cable.

Locate the serpentine belt tensioner directly below the alternator. The tensioner has a pulley on one end that releases the tension from the serpentine belt so that you can remove the belt from the alternator pulley.

Release the tension from the serpentine belt tensioner by turning the bolt head in the center of the tensioner counterclockwise with the 3/8 inch drive ratchet and a socket.

Remove the belt from the alternator pulley with your other hand while you release the tension off of the belt.

Unplug the electrical wiring harness that plugged in to the rear of the alternator. Unscrew the positive battery connection on the rear of the alternator with the 3/8 inch drive ratchet and a socket.

Locate the three bolts connecting the alternator to the alternator bracket. There are two bolts on the front of the alternator and one bolt in the rear of the alternator. Use the 3/8 inch drive ratchet and a socket to turn these three bolts counterclockwise to loosen and remove the bolts.

Slide the pry bar between the alternator and the bottom of the alternator bracket. Pry the alternator upward until the alternator comes out of the bracket. Remove the alternator from the engine compartment.

Slide the new alternator into the bracket and match the three bolt holes up. Screw the two front bolts and the rear bolt back into the alternator. Tighten the bolts down tight with the 3/8 inch drive ratchet and socket.

Slide the positive battery connection back on the rear of the alternator. Screw the nut over the connection and tighten the positive battery connection with the 3/8 inch drive ratchet and socket.

Plug the electrical wiring connector back into the rear of the alternator by pushing the connector into the socket on the back of the alternator.

Turn the belt tensioner counterclockwise again and slide the belt back over the alternator pulley. Release the tensioner so that the belt will tighten onto the alternator pulley.

Screw the negative battery cable back on the battery and tighten down with the adjustable wrench.

Crank the engine and let the engine run for about five minutes so that the new alternator can completely charge the system. Turn the engine off.

Items you will need

  • Adjustable wrench

  • 3/8 inch ratchet

  • 3/8 inch drive socket set

  • Pry bar

 How to Replace the Alternator in a Chevy Cobalt

Removal

Install a memory saver unit to the vehicle according to its manufacturer's instructions. Open the trunk. Remove the trunk floor mat and set it aside. Loosen the negative battery cable nut, using a socket and ratchet. Disconnect the negative cable from the battery and place it aside.

Open the hood. Loosen the clamp that secures the air intake tube to the air filter housing and the engine, using a Phillips screwdriver. Slide the tube off the housing and remove it from the engine. Disconnect the wiring harness from the MAF sensor. Remove the two nuts for the air filter housing, then lift the air filter housing out of the engine bay.

Make a sketch of the belt routing, using a pen and paper. Locate the square hole in the belt tensioner arm, and slide the head of a 3/8-inch-drive ratchet into the hole. Rotate the tensioner arm counterclockwise. Remove the belt from the pulleys, then slowly release the tensioner arm.

Disconnect the wiring harness from the alternator. Remove the terminal nut, then remove the battery cable from the alternator. Support the alternator by hand, then remove the three alternator bolts. Remove the alternator from the engine bay.

Installation

Hold a new alternator in position and install the mounting bolts. Tighten the bolts to 16 foot-pounds, using a torque wrench. Install the battery cable to the alternator terminal, then tighten the nut to 15 foot-pounds. Plug the wiring harness into the alternator.

Turn the tensioner pulley and air-conditioning compressor pulley by hand. Replace either one if there is any resistance or play in the pulleys. Inspect the serpentine belt. Replace the belt if there is any lengthwise cracking, fraying or glazing of the present.

Route the serpentine belt around all of the pulleys except the alternator pulley -- follow the sketch you made. Rotate the tensioner arm counterclockwise and slip the belt onto the alternator pulley. Slowly release the arm to apply tension to the belt. Make sure the belt sits between the outer walls of each pulley. Adjust the belt by slightly releasing tension, if needed.

Install the air filter housing. Tighten the retaining nuts to 13 inch-pounds. Install the air intake tube to the air filter box and the engine, then tighten the clamp. Connect the wiring harness to the MAF sensor. Shut the hood.

Connect the negative battery cable to the battery. Tighten the battery cable nut to 13 foot-pounds. Install the trunk floor mat. Shut the trunk lid. Disconnect the memory saver device.

Items you will need

  • Memory saver unit

  • 3/8-inch-drive ratchet

  • Socket set

  • Phillips screwdriver

  • Pen

  • Paper

  • Torque wrench

 How to Replace the Alternator in a Chevy Aveo

Remove the negative battery cable from the battery after loosening the retaining bolt with a wrench. Set the cable aside so that it is isolated from the battery terminals.

Locate the electrical connector in the air tube on your car. The air tube runs across the top of the engine from the air box to the throttle body. Unplug the connector and lay the wires off to one side.

Remove the clamps on both ends of the air tube. Remove the air tube from the engine and set it in a safe place. The tube runs over the top of the alternator locations so removal is required to access the alternator.

Locate the wiring harness connector on the rear of the alternator. Remove the nut from the connector with a wrench and lay the wire off to the side.

Loosen the upper and lower mounting bolts for the alternator with a socket and ratchet. Remove the serpentine belt from the pulley after releasing the tension on the belt. The tensioner is on the front of the engine; rotate it counterclockwise with a socket and ratchet to release the tension.

Remove the mounting bolts from the alternator and remove it from the engine compartment. Position the new alternator onto the mounting bracket and install the mounting bolts with a socket and ratchet. Torque the bolts to 18 foot-pounds with a torque wrench.

Install the wiring harness connector on the rear of the alternator and tighten the retaining nut with a socket and ratchet. Torque the nut to 11 foot-pounds with a torque wrench.

Release the tension on the serpentine belt tensioner with your ratchet and socket then install the belt on the alternator. Rotate the tensioner clockwise, allowing it to tighten the belt.

Install the negative battery cable on the negative post of the battery. Tighten the retaining bolt on the cable end with a wrench.

Items you will need

  • Wrench set

  • Socket set

 How to Replace the Alternator for a 1999 Lumina

Remove the negative battery cable from the battery. Loosen the retaining bolt and lift the cable off the battery terminal. Isolate the cable from the battery while you are working.

Locate the serpentine belt tensioner on the front of the engine. Use a socket and ratchet to rotate the tensioner counterclockwise to loosen it then remove the belt from the alternator pulley.

Locate the wiring harness connections on the back of the alternator. There are two, a plug-in connector and a stud with a retaining nut. Depress the locking tab on the plug-in connector and pull it out of the alternator.

Remove the nut on the “B” terminal, the stud on the back of the alternator, with a wrench. Slide the red wire with the ring connector off the stud and lay it aside.

Remove the front and rear mounting bolts from the alternator with a socket and ratchet. Three bolts hold the alternator in the car. Lift the alternator out of the engine compartment.

Position the new alternator on the mounting brackets and install the three mounting bolts. Tighten the bolts with a socket and ratchet.

Push the plug in connector from the wiring harness into the terminal on the alternator until the locking tab engages. Slide the red wire with the ring connector onto the “B” terminal on the back of the alternator followed by the retaining nut. Tighten the nut with a wrench or socket and ratchet.

Rotate the serpentine belt tensioner counterclockwise with a socket and ratchet to loosen it. Slide the serpentine belt onto the alternator pulley, then rotate the tensioner clockwise, applying tension to the belt.

Reinstall the negative battery cable on the negative battery terminal. Tighten the retaining bolt with a wrench.

Items you will need

  • Wrench set

  • Ratchet set