An alternator is an old term for electric generator that converts mechanical energy to electrical energy producing alternating current. Alternators are mainly used for recharging batteries and to power electrical loads of vehicles.

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Nissan Frontier
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How do you replace the alternator?

2000 Honda Accord V6 Here is how I went about replacing the alternator for this model. 1. Take out your car battery and have it charging while you work. 2. Loosen up your power steering container. The hoses can stay connected. Just loosen the bolt. 3. Undo all of the electrical clips that are on the fan so that you can remove the entire fan. There are two bolts on the top and one bolt on the bottom. I reached down with a 10mm socket and took it off (If you have trouble try putting the socket on the bolt and then the wrench into the socket for an easier fit. The fan should lift completely out. The hardest electrical clip will be on your lower left. That one is actually just clipped to the fan so unlike the others, you're taking it off the fan and not separating the wire plugs. Raise your fan out. 4. Take out the green plug off the alternator. 5. On the right side of the alternator is wire going in that is covered by a rubber plug. Pull off the rubber plug and use your 10mm socket to remove that bolt. 6. Loosen the pulley for the alternator. The bolt you're looking to loosen is NOT the large bolt of the pulley attached to the alternator but rather the next one back (back as in towards the back of the car). Just loosen the bolt (14mm I believe) in order to take the belt off the pulley of the alternator. 7. My next advice is to loosen the clamp that you'll see on top of the alternator (your green plug wire runs through this. Loosening this up will make taking the alternator out a breeze and is a cinch to loosen up. 8. Take out your two primary bolts holding the alternator in. 12mm socket should do this for you. 9. You should be able to pull the alternator out with ease especially if you followed step 7.

When checking the price of your replacement alternator be sure to know what the cost of your alternator will actually be. You'll see the price plus the core cost. By this they usually mean $145.99 Core $50. This means you'll pay $195.99 if you don't bring your old alternator (IE your Core) in first. If you do, you'd pay $145.99 plus sales tax.

Tools: Have a set of wrenches, sockets (14, 12, and 10mm), and a pointer magnet is highly recommended.

The whole process is rather easy if you know what you are doing. I didn't but now I do. I've tried to include the basic information I didn't know. Good luck! You can do it.


Well first off if you have the shield under your car then you will have to remove that, 2 screws under the car, 2 screws and 1 popout clip in the front passenger side wheel well(you have to remove the wheel to get to it). Once you have that off you will be able to see the alternator from under the car. Start at the top under the hood, remove your plastic piece that covers the front of your engine bay, once that is off unplug the connectors to the alternator(one is visible and the other is under a black cap you have to pop off and unscrew), there is also a clip holding the wire to the alternator on the shield piece of it(pointing toward the engine, you will see it, it pops out with a bit of force). Once all connections have been removed you will have to slip your alternator belt off the alternator(if replacing belt as well, which I do recomment you just loosen the tensioner and pull it off of all the pullies) then there is 1 bolt holding the alternator in at the top (tough to get to but what I did was stick my arm down the side with a 10mm and wrap it around in front of the alternator and take it off. Once that is removed go back under the car and there is 1 bolt holding it in that you have to remove before it comes out freely. After that your home free :)

Manuallook into getting a Hayes repair manual or similar book for your cars make, model and year. It should tell you how to install the alternator. Your local library may also have a general auto repair manual to give you a general idea. Hope this helps :) also if you have a friend or a friend of a friend that is a mechanic, maybe they can help GeneralI can give you general information on changing an alternator because I've done it twice on my 1991 Chevy Cavalier. Before you get dirty and take your car apart, test it to make sure the alternator is really bad. If you have a voltmeter, measure the voltage at the battery with the engine off. For a fully charged battery, it should be 12.6 volts or higher. Start the engine and check voltage again, now it should be 13.5 to 14.5 volts, indicating that the alternator is charging. Auto parts stores can also test the battery and alternator both on and off the car. First of all, to avoid any short circuits, disconnect the negative battery cable before working on any part of the electrical system. I once forgot to do this while working on my car. The alternator wire brushed against the mounting bracket and made some pretty good fireworks under the hood. SAFETY FIRST!!! Once the electricity is off, take off the drive belt. If your car uses regular V-belts, there will be a curved metal arm above the alternator. Loosen this bolt so you can move the alternator to take the tension off. Note: You might as well replace the belt too if it's in bad shape. If your car has a serpentine belt (one belt drives everything) there is a spring-loaded tensioner wheel. Most auto parts places sell a special tool for releasing the tension. If there is enough room, vise grips will work as well for serpentine belts. Once the belt is off, disconnect the electrical wiring from the back of the alternator. There will usually be a connector plug that snaps in as well as the "battery" wire, a red wire secured to a post on the back marked "B+". Once the wiring is disconnected, remove the mounting bolts that hold the alternator on (usually two or three bolts), and remove the alternator from the mounting bracket (Don't lose the bolts!!!). Save the old alternator, odds are you will need it to return as a core to get your core fee back when you buy the new alternator. When you buy the new alternator, you will need to tell the parts guy what make, year, model, and motor size when you buy the replacement unit. Installation is simply a reverse of removal. 80's Hondaon some late 80's Honda's you have to remove the splash pan and the left side cv axle to get it out. Me firstRead Me First!!!! I have just completed the changind of an alternator on a 1987 Honda Accord. I did NOT remove the front left axel! That is the good news. The bad news is i did some grinding around one of the engine mounts(harmless, I assure you) The car was designed where is you have to remove the axil, but let me tell you, i explored that possibility and from what i read, i tried my way and it actually did work. If you have gotten to this point 1) Car is jacked up and you have located and loosened the alternator (if you are this far, you see what i mean) Its not coming out nomatter how you turn it, pull it.. i tried it all...believe me, its not happening.... If your this far...go get you a grinder and grind on the mount for a while. It will come out and it beats removing the axil and whatever goes along with that ie..grease spillage or ? If you know what you are doing than go ahead, odds are you are not reading this page anyway, but if your like me than take my advice..GRIND IT! ,,,It works

Check out Autozones website. They have the Chifton manuels for most cars on the site. It will point you in the right direction.

Try thisbefore you remove your alternator, try this; turn your car on, open the hood, disconnect a battery terminal; if the alternator is working fine, the car should keep on running, if the car turns off, then you know you should change the alternator, I tell you this because I changed the alternator twice before I found the problem on my car. << - (Don't try that because unhooking the battery while the car's running can fry the electrical system. ManualThis is a very involved procedure, that is too complex to post here. Go to any auto parts store and purchase a repair manual for you ride. There you will find detailed instructions. Cost around $12 SimpleDisconnect the negative terminal from the battery. Disconnect the alternator's feed and secure it as to not make contact with anything. Unbolt the alt. and replace it (belt may be difficult to put back on...don't use a screwdriver though...could cause damage to the belt). Check the belt tension as per recommended tension. Reconnect alt's. feed and, then, the battery's negative.
  • Note:

Chilton's Guide is always a helpful knowledge base for auto repairs. =uD

AnswerYou should only have to take out 2 bolts and take off a belt. When replacing an alternator you usually want to replace the belt to. AnswerIt depends in large part on what kind of car you have.

On most American cars, the alternator's on top--you unhook the battery, remove two bolts and the belt, disconnect the wires, take out the old alternator and put in a new one, then reconnect everything you disconnected. The other end of the spectrum is the four-cylinder Honda engine, where the alternator is behind the engine and you need to be a contortionist to get it out.


This works for any rear-wheel-drive car, SAAB 900s, or any front-wheel-drive with the alternator in front of the engine. Basically, anything but an aircooled Volkswagen or a four-cylinder Honda (This works on six-cylinder Hondas too.)

Prop up the hood. Unhook the battery.

There are two bolts holding it in: the pivot bolt underneath, and the adjuster bolt on top. The adjuster bolt's the one sliding in the channel. There is also at least one electrical connection. Unhook all four of those. Remove the alternator belt from the car and take both to the auto parts store with the year and make of your car. Buy a new one of each. (Alternators come with a "core charge"--they rebuild them, and the core charge is to ensure you bring the old one back. But if you bring the old one in with you, there isn't a core charge.)

Go home with the new ones. Put it in its proper place in the car and install the two bolts, electrical connections and the belt. Get a big prybar and use that to pull on the alternator so it tightens the belt (when the belt is tight, you should be able to push it down no more than a quarter-inch in the middle with gentle pressure from your thumb) before tightening the adjuster bolt.

Hook up the battery and you're done.

If you carry enough tools with you, you can usually replace one of these in the auto parts store's parking lot. It takes about ten minutes.

Ford Windstar
Ford Windstar SE

How do you replace the alternator on a Ford Windstar?

Where is it, and what does it look like?

It will be usually near the top of the serpentine belt routing. It will be connected to a pulley that belt goes around this pulley. It will have a ground wire along with a connector. It will have several bolts mounting it to the mount that it is on. It will also have on it vent looking openings. If you look in them you will see copper wire coilings. It is sort of cylinder shaped, but lying long ways. I hope I explained this good.

Testing An Alternator

Many auto parts stores will offer free alternator testing, either on the car, or off.

Testing method:

  • Start the engine and allow it to reach operating temperature
  • Connect a voltmeter between the positive and negative terminals of the battery
  • Voltage should be 14.1-14.7 volts
  • If voltage is higher or lower than specification, connect a voltmeter between the battery positive (B+) voltage output terminal of the alternator and a good engine ground
  • Voltage should be 14.1-14.7 volts
  • If voltage is still out of specification, a problem exists in the alternator or voltage regulator
  • If voltage is now within specification, a problem exists in the wiring to the battery or in the battery itself.
Serpentine Belt

Before starting, make sure you have the belt routing diagram - likely inside the engine compartment somewhere, draw your own, or download one.

The belt tension is not adjustable - the belt tensioner takes care of that. If the belt is loose, the tensioner will have to be replaced.

See "Related Questions" below for more about the serpentine belt.

Replacement Procedures - 3.0l Engine
  1. Disconnect the negative battery cable
  2. Disconnect the wire from the terminal - 5/16ths (?)
  3. Disconnect remaining wiring connector(s)
  4. Detach the serpentine drive belt- if all you're doing is the alternator, you might try putting a piece of tape on the belt as it crossed the various pulleys to hold it in place.
  5. Loosen the large, horizontal oriented pivot bolt - goes through the top of the power steering bracket
  6. Remove the alternator bracket / brace - 2 bolts & one at the back of the alternator - set it aside for now
  7. Now you can remove the pivot bolt
  8. Remove the alternator- may have to pry it / weasel it out of the mounting

To install:

  1. Position the alternator on the engine
  2. Install the alternator pivot bolt and bracket / brace
  3. Tighten the:

    * alternator brace to 15-22 ft lbs

    * pivot bolt to 30-41 ft lbs

  4. Install the serpentine belt
  5. Re-connect the 2 wiring harnesses, and the wire held on with the nut
  6. Connect the negative battery cable
Replacement Procedures - 3.8l engine

Changing the alternator on the 3.8 is very easy. There are only 3 bolts holding it on. There is 1 wiring plug and 1 battery / hot wire connected to it.

  1. Disconnect the positive cable from the battery as to avoid any electrical shorting,this will clear any codes and the check engine light if it was on.
  2. Remove the nut from the single wire on top of the alternator. Screw the nut back on so you don't loose it.
  3. For the wiring plug, just push in on the drivers side of it and pull up and it will come off.
  4. Remove the belt - grab the backside of the belt the runs from the top of the alternator towards the back of the van, pull real hard on it towards the front of the van, (be careful not to pinch your fingers between the belt and the pulley) and the tensioner will give allowing you enough room to slide the belt off of the alternator.

    See "Related Questions" below for more about the serpentine belt

  5. Then remove the 3 mounting bolts and voila - it's off!
  1. Start with remounting the alternator with the 3 bolts
  2. Hook up your wire - using that nut you did not loose - and wiring plug
  3. Re-install serpentine belt - make sure the belt is around all of the pulleys and lined up correctly and pull again towards the front of the van to slide it back on - careful not to pinch your fingers between the belt and the pulley!
  4. Hook the positive wire back up to the battery and then have an assistant to just bump "NOT START" the engine as to get the belts properly aligned.
  5. Take a visual inspection and make sure the belts are positioned correctly on the pulleys and then go ahead and start the van.

Good luck!

To remove the alternator on a 1998 ford Windstar if it is a 3.8L engine: FIRST - Remember to disconnect the battery!! Then, remove the tension on the belt. There is a tensioner towards the rear of the engine. Use a good box wrench and pull as much as you can because the tension is hard on those engines. Once you have that off, remove the 3 bolts and they just have to be taken off after that you have to remove the ground. Make sure that it is clean. When reinstalling, put some die electric grease on it. There is 1 electrical connector; unplug it. Also put on reassembly die electric grease in there for better conductivity. You should have the alternator off...just do the reverse to put in the new one.

If the 96 is like the 98, loosen the mounting bracket bolts, make sure you remember which way the serpentine belt goes on, pull off the belt, remove alternator, replace with new one, put belt on, use a pry bar to re-tighten the alternator and tighten bolts.

It was about the easiest thing I have done on my '96 with a 3.8L engine. First always disconnect the battery when removing charging system components for safety. Rather than loosen the tensioner, I was able to grab the serpentine belt past the alternator with my hand and pull against the tensioner to gain enough slack to slip the belt from the alternator pulley with my other hand (careful don't get pinched) . Next remove the cables and electrical connectors. Now you can remove the mounting bolts and remove the alternator. Compare the replacement alternator to the one you removed to insure they are similar enough to install the new alternator. Reverse the process above... Install mounting bolts and torque appropriately, connect cables and connectors, route the serpentine belt, pull slack on the belt and slip it over the alternator pulley, reconnect the battery and check for proper operation. Even with the trip to the parts store, it probably took me less than an hour.

It is not hard to do...the alternator is right on top. Just take the serpentine belt off, remove the bolts and plugs, and bolt the new one in. be careful not to torque the top screw too much or it will break off.

Disconnect the batter cables so you, and car don't get a shock. remove the 2 wire connected to the alternator. One is a Plug, push in on the l/s of the clip and lift up. The other one is held on my a small nut on a stud, Once this is done take a picture of write down the routing of the Serpentine belt, so you know that will be correct when your finished. There are just 3 bolts, loosen them all together. Before you remove the bolts even though they are loose, pull towards you really hard on the belt and pull it off the pulley. Remove the 3 bolts, remove the alternator, replace alternator, tighten 3 bolts, then pull on the belt again and put back on in same orientation, reconnect wire to alternator, reconnect battery, start engine

I just did it. It took about an hour. The instructions to replace a 2000 Windstar's alternator work for the 2002. See: How do you replace the alternator on a 2000 Ford Windstar.

I found that wearing an old work glove made it much easier to pull the belt against the tensioner. Also, when you replace the belt, make certain that the belt is inside the grooves of each of the pulleys. It was off the first time I replaced it. Don't bother trying to push it back; take it off the alternator again and re-thread it.

Once I finished, I started the engine and noticed some whining from the belt. I also noticed that it rode a bit outside of the polished spot on the pulley immediately below which rides on the outside of the belt. I double-checked all the pulleys again, and they were all on. After driving the van the couple of miles to the auto parts store to return the core, it quieted down.

First you disconnect the battery. then you need to take the belt off by the back pulley. But you don't need to take it all the way off. Just so you get the alternator belt off. I just replaced the one on my 1997 . then you have three bolts, and one small nut to remove . Then put all back together the way you took them off. Jon

you have to remove belt and disconect neg battery cable 3 15 mm bolts hold alt on,1 plug then pos.

You must have the car well off the ground because the best way to get to it is from the back of the engine. There's a nut back there that's hidden. Might as well change the rear spark plugs while your there. To change the number 6 you have to remove the alt. bracket anyway.

Removing the belt and alternator and replacing the new one is just as stated above, but putting the belt back on isn't such an easy task on my 2000 windstar. It is very difficult to pull back on the belt to replace it back on the pulley. It takes a fair amount of pulling and when you pull on the belt all the pulleys move so you can't easily place it over the alternator pulley. To remedy this jack the car up on the front passenger side and remove the front passenger side wheel. Then securely place jackstands under the van so that you can easily slide under the car. Locate the belt tensioner which is the small pulley closest to the rear of the van. Call a buddy to help at this point. Have the buddy stand by at the topside of the the van. Place a 13 MM boxend wrench on the retaining bolt for the Belt Tensioner Pulley. Push the wrench toward the front of the van as if trying to remove the bolt (counter-clockwise motion) Push it as far as you can. While you are holding the tensioner have your buddy slip the belt back over the alternator pulley. Once this is done slowly release the tension on the tensioner. Replace the wheel, lower the car and give your buddy a cold drink!

Perfect tool to release the ford windstar 2003 belt tensioner:

socket wrench breaker bar, 1/2", remove the head (don't know the

name), Normally you can get those socket wrench breaker bar from 15 to

18 inches, I guess. If the bar is too long, you may remove air

conditioner part (don't know how to say the name, you will know what I

am taking about when you get there, )

Car Electronics and Lights
Car Batteries

How do you test a voltage regulator?

You just need an accurate voltage meter.

Connect the meter to the poles of the battery. Start the engine and avoid spinning her up, even not for a short moment. The reading of the meter now can be anything; a reading lower than 12.6 volt indicates a weak battery.

Slowly increase the engine speed. The meter reading should increase too, but will get "catched" at an engine speed somewhere at 1000 rpm. (8001200) From then on the reading will stay "locked". It should be 13.8V; 0.5V higher or lower is the limit of what is acceptable. A voltage too high is NOT good: it will ruin your battery and wear out bulbs and other equipment!

A voltage regulator is good when the reading hardly reacts to change of engine speed or to adding power consumers like electric window heaters or main headlights.

Ans 2: sometims the voltage regulator is faulty when the remainder of the alternator is OK so it's worth considering replacing the regulator first because it is less expensive and sometimes it can be removed and replaced without taking the alternator off the car.

Car Batteries

Will a bad battery ruin a new alternator?

Yes, it can. A completely dead battery can blow the alternator diodes, at least in older systems - I am not so certain about newer systems, whether or not they are protected against this annoyance. In any case, the alternator is not generally designed to charge a battery from scratch, but just to keep it charged during normal use. The alternator will not be completely ruined, but it will not function until the diodes are replaced.


How do you tighten alternator belt for 1996 accord?

There is a tensioner bolt that is connected to the alternator. You have to screw in the bolt, which will pull the alternator out and tighten the belt.

Car Fuses and Wiring

Is there a fuse on an alternator?

no there is not a fuse built into any alternator that i have seen to date (been a mechanic for 10 yrs) HOWEVER most vehicles have a charging fuse located either in-line or at the fuse panel so that if the rectifier or voltage regulator goes out the battery does not receive too much voltage or the wrong type of voltage ac versus dc

in short no the alternator doesn't but the vehicle should have one in the alternator circuit

Car Batteries

Can you drive if my battery light stays on?

yes but you shouldn't if alternator is not charging battery is bound to go dead and you will get stranded somewhere.

Electrical Engineering

What happens when the direction of rotation of alternator is reversed?

Nothing. It will work in either direction.

Ford Contour

How do you replace the alternator on a 1999 Ford Contour?

1. Put the front of the car on jackstands and dis-connect the negative battery cable.

2. Remove passenger side wheel and lower splash guards. Using low profile 3/8" socket wrench or breaker bar, remove the serpentine belt from the alternator pulley.

3. Dis-connect the passenger side tie rod from the knuckle.

4. remove the driver side wheel.

5. Get 3 or 4 feet of extensions for your 3/8 socket wrench and feed them through the driver side wheel well to the upper bolt of the alternator. Yo may need to secure the socket & extensions on the bolt from up top then get back down to the driver wheel well, but it's worth the few seconds. Remove the upper bolt.

6. From below the car, loosen the lower bolt, but do not remove.

7. There is a small bracket on the alternator between mounting bolts. Remove the 10mm bolt that secures the bracket to the block.

8. From above, pry the upper tab from the mounting bracket.

9. Below the car, hold the alternator while removing the lower bolt.

10. Dis-connect the electrical to the Alternator.

11. Maneuver the alternator out through the passenger side wheel well. Takes a little thinking, but it'll come out.

12. Transfer the small bracket to the new alternator.

13. Feed the alternator in through the passenger side and make electrical connections.

14. Secure the lower alternator tab and hand tighten the lower bolt.

15. Pivot the alternator up. The upper tab may not easily fit into place. Tighten the 10mm bolt in the center bracket to the block. This will press the upper tab into place.

16. Install the upper bolt and hand tighten. Fully tighten the lower bolt now.

17. Use extensions from the driver wheel well to tighten the upper bolt.

Remainder of this project is simple re-assembly. An experienced shade tree mechanic can do this alternator R&R in under an hour after his tools are set out.

Answer- 4 cylinder engine

If you have one of the 4 cylinder models like I do, its a major PITA. You can get the Haynes manual for the car and that helps somewhat. You really just have to remove the air intake assembly (big black thing on top of engine) to get at the alternator from the top and remove the wires going to it, then you have to drain the oil and remove the oil filter to get at the drivebelt from the side (through the wheel well) and loosen it to the point you can get the alternator out. Hope this helps, otherwise get a Haynes repair manual.

Ford Explorer XLS

Why does the alternator make a clicking noise?

What you are hearing is the clutch on the air conditioning pump engaging... the alternator doesn't make any noise unless the bearings are going bad and then a grinding noise will be heard.

Car Batteries

Can a motorbike light be run with no battery?

only if the engine is running and the alternator is in perfect working condition!

Fuel and Engines
Car Batteries

Can over voltage kill a car battery?


Electrical Engineering

How does a bicycle dynamo work?

The movement of another body is transmitted to a rectangular coil of wire that is inside a U-Shaped magnet. The motion of this coil of wire cuts the magnetic flux in the magnet. Faraday once stated that-Whenever there is a change in magnetic flux linked with a circuit there is an induced current and the strength of this induced current is directly proportional to the rate of magnetic flux-. So according to this rule when the magnet is in motion it is constantly cutting the magnetic flux, and as it does this there is a current that is induced (eddy currents). However a dynamo can either be A.C or D.C according to the brushes and number of commutators used (Flemings Right-hand rule). If we refer back to Faraday's rule it says that the strength of this induced current is directly proportional to the rate of magnetic flux. This rule can be seen practically in a bicycle that has a dynamo.

Hope i have helped you lot

Nissan Sentra

How do you replace the alternator on a 1997 Nissan Sentra?

I did it on a 95 (97 should be similar). You start by removing negative battery post, removing radiator fan that's close to the alternator, and move away any little hose(s) and/or wires around it to gain access to the alternator.

Loosen the locknut on the adjuster, then you can turn the adjuster and the alternator belt will come loose. Loosen the alternator mounting bolts (2 of them), alternator will come out. Installation is the reverse.

It's very tight in there doing this way, but you don't need to jack up anything, or removing anything major. Patience, good tools, and little bit of time. New (not rebuilt) alternator will cost around $110 shipped.

1996 Sentra: Just did it. Did not remove radiator fans but removed bracket (1 12mm bolt) that has the cable tie-down and top bolt of alternator. '96 does not

have any adjustments on the alternator, as in for belt tightening. I ended up removing the idler pulley to loosen the belt. There are two (2) bolts on the bottom, one of which is tough to see or access. I removed the overflow reservoir for coolant just so I could see it.

Going back in, I almost needed an assistant to start the top bolt, as I applied force to get the alternator in position. Patience advice is good; try to start before 3:30 PM if you want to finish the same day.

I just did this on a 97 Sentra. It is a big pain. That alternator is really hard to get to. You have to remove the radiator fan...You also need to remove the coolant hose and the bracket that holds your wires in place. The bolts on the bottom are really hard to get to and maneuver around and are tight as hell. It is very tight quarters in there. Hard to loosen anything. Once you get all your bolts out, and remove the belt (which can be done by simply loosening the alternator and rocking it back and forth to release tension) you really need to work that thing back and forth to get it out. And it is very tight trying to get it out of there. Installation is basically the opposite. Getting the belt back on is the hardest part. There is a tension rod on the lower left side (looking at the engine) w/ an 8mm bolt on it. ONce again very hard to get to and work on w/ tools. This needs to be loosened in order to set the tension for re-installing the belt. Took a long time and a lot of muscling to get the belt back on there. Once it's on tighten that adjuster rod and make sure yer belt is tight. Replace everything and you're good to go. All in all, frustrating and poorly designed. Patience and small hands will help you out alot.

I just changed the alternator on a '96 Sentra - day one involved removal of old alternator - passenger side fan and overflow tank had to be removed. I left the rad hose as-is. The used $75 CDN alternator from recycler was not exactly the same. After a few frustrating hours trying to get the "new" one in, I realized that the casting boss near the idler was about half an inch wider, therefore the original 14 mm/M10 bolt was about half an inch too short. I went to a fastener store, bought a 40 mm long M10 bolt and thought I was in business, until realizing that the same thicker boss was also contacting the threads of the tensioner rod. A few minutes of filing off some material off the bottom of the boss provided the clearance required to no longer contact the tensioner bolt. As well, the tensioner was stuck in place, making belt replacement impossible. The alternator had to be removed again, the tensioner pulley 14 mm bolt loosened so that the pulley could be slid in its slot. We put the belt back on, and tightened the 14 mm tensioner pulley bolt, then the 8 mm tensioner rod and then the 14 mm tensioner set screw bolt. Frustrating, yes, but mostly because the replacement alternator wasn't exactly the same, so double check before installing. It will likely still work, but may need some minor modification.

Car Batteries

How can you tell if it's your battery or alternator that's bad?

Battery or AlternatorThe battery provides the juice needed to operate the starter motor. It also provides power to the electrical and electronic devices in your car when the engine isn't running. Every time you start your car or play the radio or operate the power seats or windows while the engine is off, you drain the battery a bit. The alternator -- which is really a generator -- replenishes the battery when the engine is running and provides power to your car's electrical systems when the engine is running.

If your battery is totally drained, the car will fail to start. You may be able to "jump-start" the car using another vehicle. But why is the battery dead? If you left the lights on, even a small dome light inside the car, that could have drained the battery. Jumping the car and then letting it idle for a while can replenish it, but if the battery is old and near the end of its service life, it may not be able to take and hold a charge any longer.

Or the problem could be the alternator. Perhaps it is no longer able to recharge the battery. If that's the case, the battery -- even a brand new one -- will eventually run down, and rather quickly, because your car's electrical system will be running off battery power, instead of from power supplied the alternator. When the battery goes dead, your vehicle will stall, because there is no power to run the electrical systems.

Answerwith the vehicle running(even if you have to jump start it), remove one of the clamps off of the battery. if the vehicle dies immediately, you have a bad alternator. if it runs for a little while before it dies, a bad battery.

This might have worked on a car thirty or more years ago but is actually potentially very harmful for a modern car. The cars now are designed to have a battery as an integral part of the charging system and if it is disconnected can send voltage spikes through the system and burn out your computer. Also the alternator is designed to put out a certain amount of current and this test would only tell if the alternator is putting out enough current to keep the engine running, not if it puts out enough to keep the battery charged, run the lights etc. The only real way to tell if the alternator works is to put a voltmeter on the battery and see if the voltage goes up after the car is started. Then to tell how well it works, put an amp meter in line with the alternator and see how much energy it puts out when the various circuits are turned on.

A bad battery can be hard to detect sometimes. It can work fine then all of a sudden fail to start. Then next time you try it works fine again. The best way to test it is with a load tester at an auto parts store or shop.

Pontiac Grand Am
Grand Am GT
Grand Am SE

How do you install an alternator belt on a '94 Grand AM?

you losten the belt with the tensioner pulley. it is located below and to the rear of the alternator. it will take a 13mm box end wrench and I also use a 17mm box end for leverage. you will pull the wrench toward the rear of the car and slide the belt off of the alternator.

Ford Taurus
Ford Explorer
Ford Focus

How many watts can the stock alternator handle on a Ford Focus?

it is not watts, but amps. If you are just adding a stero you should be fine. But, if you are adding several amps and equipment, check into a higer amp alternator (good luck on a Focus) and dual batteries with an isolator. If you run dual batteries without the isolator it will not work as well.

How does an alternator work?

Community Answer 1

The alternator houses a rotor that is connected to your engine. The engine will spin this rotor depending on how many RPMs youre producing. The alternator also houses a ring that goes around this rotor. Basically, the rotor creates a magnetic fieid as it spins and the ring acts as the catcher and harnesses that energy in the form of AC power. However, your battery uses DC power so before it sends this power out it converts it to DC.

Your alternator should cause about 14V to flow through your battery even when all the electric components in your car are turned on. Anything under 12 might be cause for concern.


Community Answer 2

The alternator consists of a spinning set of electrical windings called a rotor, a stationary set of windings called a stator, a rectifier assembly, a set of brushes to maintain electrical contact with the rotor, and a pulley. All of these parts except the pulley are contained in an aluminum housing. Today?s alternators use compact, electronic voltage regulators that may be housed inside the alternator or the voltage regulator function may be handled by the vehicle?s powertrain control module (PCM).


Community Answer 3

The alternator develops electrical power by converting rotational energy into electrical energy through constantly varying magnetic lines of force that intersect wires. The rotor receives excitation voltage from the battery. There are two slip rings supplying the rotor with power. One is typically grounded, and the other is fed from a regulator that varys the pulse width, and thus the voltage, to the rotor. The rotor spins and induces a rotating magnetic field into the stator. The stator is wound in a three phase delta configuration, and generates alternating current, with frequency dependent on speed. The stator is connected to a full wave bridge rectifier (six diodes) that converts the AC into DC. This output is connected to the battery through a heavy cable. Since the rotor and stator have multiple poles, the AC frequency is relatively high. Since the alternator is three phase, the ripple on the DC output is relatively small.


Community Answer 4

Winding a coil of wire around an iron core can make a magnet. If a magnet is passed near a wire, an induced current will flow in that wire. If many magnets are rapidly passed over a coil of wire, much more induced current will be produced. If many magnets are passed over several coils of wire, even more current will be produced. Although Alternators vary by manufacturer, there are two elements common to all alternators; the stationary stator and the rotating rotor. The stator consists of three sets of individual windings wound around a laminated circular iron stator frame. Each individual winding is made up of seven coils, which in turn are made up of several individual loops all connected in series. Each coil and each loop are connected so as to increase the total voltage output. Each group of windings has only two leads, one for current to flow in, and the other for current to flow out.
a moving magnetic current cuts through wires producing a current in the coil turning rotor driving belt

Ford Expedition
Ford Expedition Eddie Bauer
Ford Expedition XLT

How do you replace the alternator on a 1998 Ford Expedition?

Find the belt tensioner.There is a square hole to insert a breaker bar.Rotate the tensioner to relieve tension and remove the belt.There is a sticker with a picture showing how it goes back on.If you can find it changing it is straight forward. Just remember to disconnect the battery negative terminal.



Do yourself a favor. When buying a New Alternator have them check it before taking it home? I had a bad incident that I ended up with, 3 bad alternators in one day, 3 different stores. Last store check it before I took it home and everything was good. I ended up changing it 3 times. Make sure they also change the pulley.


Removal & Installation

1. Disconnect the negative battery cable.

2. Rotate the drive belt tensioner away from the drive belt and remove the drive belt from the alternator pulley.

3. Detach the electrical harness connectors at the alternator assembly.

4. Disconnect the positive battery cable and remove the nut and washer.

5. Remove 2 front alternator bolts.

6. Remove the rear alternator support bracket retaining bolts and the support bracket.

7. Remove the alternator from the vehicle.

To install:

8. Place the alternator in position and loosely install 2 front alternator retaining bolts.

9. Install the alternator bracket and 3 alternator bracket bolts. Tighten to 84 inch lbs. (10 Nm)

10. Tighten 2 front alternator retaining bolts to 19 ft. lbs. (26 Nm).

11. Connect 2 electrical hardness connectors to the alternator assembly.

12. Connect the positive battery cable and install the nut and washer. Tighten the nut to 72 inch lbs. (8 Nm).

13. Rotate the drive belt tensioner away from the drive belt and install the drive belt on the alternator pulley.

14. Connect the negative battery cable.

15. Start the engine and check for proper charging system operation.

Ford Taurus
Mercury Sable

How do you replace the alternator on a 1996-1999 Taurus - Sable?

Preliminary Notes
  • See "Related Questions" below for more specific details on the DOHC alternator replacement procedures
  • Many repair shops and auto parts stores offer inexpensive or free alternator & battery testing.

    Be sure to test before replacing!

  • If you have the engine with the dual overhead cam it is not easy, I just did it and it took me 12 hours.

3.0 12 valve, Vulcan engine, the alternator is on the top in the front.

  • Release the serpentine belt tensioner and remove the belt
  • There is one wire bolted to the alternator and one plug in - remove the wires
  • Loosen and remove the bolts (three bolts)

3.0 DOHC (dual overhead cam) 24 valve engine

See "Related Questions" below for more specific details on the DOHC alternator replacement procedures

  • Lift and chock the rear wheels
  • Remove the passenger-side tire
  • They tell you to remove the steering arm, but I have been able to get it out without doing that.
  • Release the belt tensioner and remove the serpentine belt.
  • You must then reach up under and undo the wires (one bolted on and one plug in) and
  • Still working from through the wheel-well, remove the two bolts from the bottom and one from the top.
  • If you twist the alternator around as you drop it you can usually get it out without undoing the steering arm.


There is a mega-fuse on the front of the fuse box under the hood. It has a positive and negative wire bolted to it, remove the bolts, pull the fuse out and shake the little tabs to see if they are loose.

If they are loose it will cost you $4.99 for a new one at Autozone.


Find belt tension idler arm and release belt making sure you draw a picture or check to see that there's a routing diagram of how the belt goes and then you need to locate the upper and lower bolts for the alternator usually one on the top ear and one on the bottom ears, then disconnect harness and ground wires and repeat in reverse order. Hope that works. for you.

first disconnect the battery for safety. unhook all wire connections to the alternator (i think there is two of them). loosen the two bolts on the alternator that secure it to the engine. put a long pry bar on a wrench on the bolt for the alternator belt tensioner, making the belt loose. then remove the alternator (it may be in tight and require some strength). install new one in reverse order.


I own a 1997 Mercury Sable Station Wagon, and did own a 1992. The alternators look to be in about the same position on both cars which have the 3.0L engine with standard overhead valves, right up top and easy to get to.

First, undo the cables on the battery posts. Then "unsnap" the electrical connections on the alternator, and unscrew them.

Now you don't really have to, but I'd advise it because it makes everything so much easier and gives you room to work. Remove the radiator over-fill tank, after the car has sat cooling for a while. First compress the rubber hose clamps with a pair of large pliers and pull the rubber hoses off. Channel Lock pliers work good for that. Those hoses will be fused to the metal fittings by the heat, but, gently twist them back and forth until they come off. A dab of dish soap inside the rubber hose ends will make installing them back on much more easy.

The over-flow tank is the large white plastic tank on the passenger's side of the engine compartment that blocks your sight and access to the belt, pulleys and bolts. Plug all the removed rubber hoses, and white tank nozzles, with compressed paper towels with Saran Wrap rubber-banded around the "open" ends if you don't want anti-freeze and water all over the place.

Relieve the pressure on the fan belt, turning clockwise with the bolt on the automatic adjuster (Tensioner) and remove the belt. I use a 15mm box wrench with the open end "ground down" to fit inside one of my floor jack handle extensions because it a little too tight to get a large socket wrench and socket in there. But a long "breaker" bar with a 15mm socket on it might work too.

There should be a diagram on the underside of the hood as to how it goes back on, plus it will also show you what each part on the belt is.

Remove the three smaller nuts that hold a top upside down "Y" bracket on the intake manifold and alternator then the two long large long bolts holding the alternator in place. Install it back in the same way you took it out.

The two large long bolts should be snug, about 25 foot lbs, or "tight" and then 1/4 of a turn tighter, if you don't have the wrench to check the tightness. The smaller nuts just hold the top "Y" bracket and should just be very snug.

Put everything back together the same way and order you took it off and it should work fine.

Go to autozone and pay the $16 for a Chiltons repair manual for your car. It gives a play by play with pictures. There are only three bolts, one nut and the cables to disconnect. Just be sure and unhook the negative cable from the battery first.Its mounted on the same mount as the PS pump.


Disconnect the battery, remove the right side wheel, remove the dust covers inside the wheel well, loosen the engine and transmission mounts and with a floor jack place a piece of 2x4 wood on the floor jack to protect the engine's oil pan, and lift up the engine just enough to squeeze the alternator out through the wheel well,

If you're looking for the alternator, and don't know what it is, chances are you probably shouldn't be messing with it. However, it is located on the very top of the engine, on the passenger side. You'll see some vents in it, in which you can see many copper wires woven around inside. Not professional directions, but it'll get you close.

Electronics Engineering

What is the difference between alternators and dynamos?

Alternators produce AC, which is rectified by diodes if DC is needed. Dynamos produce DC by using a commutator.

Dodge Ram
Pontiac Sunfire

How do you replace the alternator on a 1997 Pontiac Sunfire?

get a repair book at a pepboys or other auto store. The book will help you with a lot of questions including your alternator question. the book runs about 15-20 dollars. it's a good investment

Remove the neg. {black} battery cable.

Disconect the two sets of wires from the alternator {one is bolted onto a post, the other is a plug}.

Remove the tension on the belt buy moving the tensioner with a wrench or the special tool. {the tensioner is a pulley on a spring loaded arm bolted to the block, refer to the belt routing sticker under the hood}

Remove the three or four bolts that mount the alternetor and remove it.

The install is the reverse of removal, the belt tension is self adjusting.

Make sure the battery is charged.

Car Starting Problems
Car Batteries

Can an alternator blow if jump starting another car?


Normally speaking, with a typical jumpstart, it SHOULD NOT damage an alternator.

LONG ANSWER (not a typical jumpstart):

The only ways I even remotely see jumpstarting a vehicle damaging one's alternator are:

1. If the alternator is already severely or, in rare circumstances, slightly damaged.

2. The amperage required by the other vehicle's starter severely exceeds the maximum output amperage of the alternator AND the maximum (cold [?*]) cranking amperage of the battery together.

Usually, in most typical jumpstarting cases, the battery in your vehicle will supply any excess amperage required above the altornator's output.

3. If one's vehicle is MUCH smaller than the vehicle it is jumpstarting and one's vehicle does not have a battery with a maximum (cold [?*]) cranking amperage required to start a MUCH larger vehicle --- typically a larger vehicle means a larger motor and therefore a larger starter which will require a (significantly) higher amperage to turn the motor over with the (minimum) troche and speed required to start the vehicle's motor. (Such as in my story below.)


4. If the battery in one's vehicle is extremely low in power --- such as a vehicle that was recently jumpstarted and did not have enough running/charging time pass to get a good charge on the battery before attempting to jumpstart another vehicle --- and cannot produce the amperage required by the other vehicle's starter, the alternator may/will be forced to supply almost all the amperage required by the other vehicle's starter; which can easily exceed the maximum output of one's alternator depending on the maximum amperage rating of one's alternator (with a possible output range of a factory alternator of being anywhere from 50 to 150 amps for a typical car or small truck and 125 to 350+ amps for a truck) and the amperage required by the other vehicle's starter.

REFERENCE: self-experience with many bad alternators (Seven in two and a half years to be exact!) and jumpstarting in my first car ('95 Honda Civic LX)


Only once did my alternator die shortly after jumpstarting a vehicle, a big heavy duty, I cannot even remember the manufacturer anymore, v8 truck (I did not even think to turn off the sound system, but I did turn it down, which was still pulling nearly 20 amps by itself, but thats out of the almost 180 amps it pulled turned up as loud as it would go before the sound started to get distorted) his started required (guessing) around 650 amps (cold start on 40 degrees F night) my alternator rated at 85 amps and my battery being 5 years old and only ratted at 350 amps and 425 max cranking amps. Needless to say that this also melted the insulation of the 2 gage jumper cable I used. (I should have known better than to do that, but I wasn't thinking about it at the time.) Shortly after the cables started smoking I gave up and less than 10 miles down the road my batter light came on, by the time I got home the battery itself was down to 7.14 volts from running the headlights and windshield wipers for the next 25 miles (30-35 minutes.)

After all was said and done I've replaced the alternator and decided to go ahead and replace the battery, just incase it was also damaged. Since then I don't think I ever went more than 7 months without the alternator failing, thankfully Autozone has a 1 year warranty on the alternator and battery so I never had to pay for the part again, all the alternators for the Honda were unfortunately "refurbished" which is probably why they kept failing, the third alternator ruined my battery by pulling 11.5 amps to ground when the motor was off (but when the car was running, it could charge the hell out of the battery.) The forth alternator was producing a crazy 37+ volts when the motor was running. Thankfully; after the second alternator, I put a voltmeter in the 12v auxiliary plug (cigarette lighter); because, that high of voltage could have easily ruined a lot of things like the battery, computer, radio, amplifiers, and many many more items if left unnoticed. All the other alternators just died on me without a (noticed) reason.

Car Computers and Sensors
Chrysler LeBaron

Where is the voltage regulator on 1990 Le baron?

The engine computer is also the voltage regulator.


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