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How to Replace Alternator 01-06 BMW 325Xi

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How to Replace Alternator 01-06 BMW 325Xi

Created on: 2019-08-14

Watch this video to learn how to replace the alternator in your 01-06 BMW 325Xi and similar E46 3 series vehicles. 1A Auto shows you how, step by step!

  1. step 1 :Removing the Radiator Fan and Shroud
    • Disconnect the negative battery cable by loosening the 10mm nut
    • Remove the air collector push pin retainers
    • Remove the air collector
    • Disconnect the two electrical connectors on the passenger side of the fan shroud
    • Remove the T25 screw from the passenger side corner of the fan shroud
    • Remove the push pin retainer from the driver side corner of the fan shroud
    • Loosen the radiator fan clutch using a fan clutch tool
    • The fan clutch is reverse threaded
    • Remove the fan and fan shroud
  2. step 2 :Removing the Air Filter Box
    • Disconnect the MAF electrical connector
    • Loosen the air filter box hose clamp
    • Disconnect the air tube from the air filter box
    • Release the air filter box lever latches
    • Remove the air filter box lid
    • Remove the air filter
    • Remove the two 10 mm bolts securing the air filter box
    • Disconnect the wire from the retaining tab
    • Remove the air filter box
  3. step 3 :Removing the Alternator
    • Turn the AC belt tensioner clockwise with a 16 mm socket
    • Remove the AC belt
    • Release the AC belt tensioner
    • Loosen the serpentine belt tensioner with a 16 mm socket
    • Insert a pin through the tensioner hold holes
    • Remove the serpentine belt
    • Remove the 16 mm idler pulley bolt to remove the idler pulley
    • Loosen the lower 16 mm alternator bolt
    • Tap the lower alternator bolt to loosen the mount bushing
    • Remove the 16 mm lower alternator bolt
    • Pull the alternator loose
    • Disconnect the alternator electrical connector
    • Remove the 17 mm battery cable nut and disconnect the battery cable
    • Pull the alternator from the air tube
    • Remove the alternator
  4. step 4 :Installing the Alternator
    • Remove the alternator intake cap
    • Remove the battery cable nut
    • Set the alternator in position
    • Reconnect the battery cable and tighten the 17 mm nut
    • Reconnect the electrical connector
    • Push the intake into the air tube
    • Align the mount holes
    • Install the lower alternator bolt by hand
    • Install the upper alternator bolt with the idler pulley. The pulley has an alignment tab that fits in the slot of the alternator mount
    • Torque both 16 mm bolts to 30 ft-lb
    • Slide the serpentine belt over the crank pulley, to the right around the power steering pulley, loop the belt around the tensioner pulley, and back over to the water pump pulley, bring the belt over the alternator pulley, then under the idler pulley
    • Loosen the tensioner with a 16 mm socket to get the belt under the idler pulley, then remove the pin and then release the tensioner
    • Loosen the AC tensioner with a 16 mm socket
    • Install the AC belt around the crank pulley and the AC pulley, and over the tensioner pulley
    • Release the AC tensioner
  5. step 5 :Installing the Radiator Fan and Shroud
    • Lower the radiator fan and fan shroud together
    • Tighten the fan clutch onto the water pump pulley by turning it clockwise
    • Torque the fan clutch nut to 22-29 ft-lb if able
    • Install the fan shroud push pin retainer on the driver side
    • Install the fan shroud T25 screw on the passenger side
    • Reconnect the two electrical connectors on the passenger side of the fan shroud
  6. step 6 :Installing the Air Filter Box
    • Lower the air filter box into position
    • Install the two 10 mm air filter box bolts
    • Install the air filter
    • Slide the air filter cover onto the air tube
    • Secure the air filter cover with the lever latches
    • Reconnect the MAF electrical connector
    • Tighten the air filter cover hose clamp
    • Insert the air collector into the air filter box
    • Secure the air collector with the push pin retainers
    • Reconnect the negative battery cable and tighten the 10 mm nut

Tools needed for replacement

  • General Tools

    Hammer

  • Hex Wrenches

    5mm Hex Wrench

  • Pliers, Cutters & misc Wrenches

    Side Cutters

  • Ratchets & Related

    Socket Extensions

    Torque Wrench

    Ratchet

  • Screwdrivers & Related

    Flat Blade Screwdriver

  • Sockets - Metric

    16mm Socket

    17mm Socket

    10mm Socket

  • Specialty Tools

    Trim Tool Set

    Fan Clutch Wrench

  • Star Drivers & Sockets

    T25 Socket

    T20 Socket

  • Wrenches - Metric

    17mm Wrench

Installation Video
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What's up, guys. I'm Andy from 1A Auto. In this video, I'm going to show you how to replace the alternator in this 2001 BMW 325XI. If you need this part or other parts for your vehicle, click the link in the description, head over to 1AAuto.com.

With the trunk open, we're on the right side or the passenger side, there should be a cover that goes right here. This vehicle doesn't have one, but you're going to want to remove that cover. Battery is located right here. First thing I'm going to do is take a 10 millimeter socket and ratchet, loosen up this nut for the negative terminal. And that's loose, slide off the cable, slide it out of the way. I'm going to take these push pins out right here. I'm just going to use some side cutters, get this center pin, pull that up, and then slide it out. Be careful not to cut the ... Get those out. Just grab this piece, slide it out.

We're going to disconnect this connector right here, just push down on that, slide that out. There's another connector right here. I'm going to slide the wiring out first, just like that, and then connector will come out. Just slide that to the side like that. I'm going to take a T25 and a ratchet, take this screw out right here. I'm just going to use this trim too from 1AAuto.com to take this push clip out. In there, pull that out. All right, now that is loose. But we need to do is we need to take the fan off, because the fan has to come out with the shroud as one. What we need to do to take the fan off is we need to disconnect the fan clutch from the engine side. This is attached to one of the pulleys right there. So sometimes these are somewhat difficult to get off, so what we're going to do is use this tool. We actually sell this at 1AAuto.com with many different sizes. This happens to be the 32 millimeter. That's going to slide on there, and then we slide this one. And with a pneumatic air hammer we're going to give it a couple bumps and it's going to loosen up that nut, and we should be able to get it off.

All right, so now I'm going to take the tool ... Now, this fan clutch happens to be on there reversed thread. So it's going to seem like you're tightening it, but you're actually loosening it. So we'll go like that. Put our air hammer on there, make sure you wear hearing protection and eye protection. All right, so that's loose. It took a little bit of effort, but I got it. Now, you can slide the tool off. I'll just move it a little bit. There we go. You should be able to just spin it off like that. You might need the tool once in a while, or you could use a wrench that fits, 32 millimeter wrench. All right, now I'm just going to keep loosening this up. Be careful, you don't want the fan to fall. You don't want it to smash into the radiator, especially if you're going to reuse the radiator. If you're replacing it, it's not a big deal. As I get closer to the end, I'll just move the fan and just grab the blade. And there we go, now I can slide this right out just like that.

I'm just going to disconnect this connector to the mass airflow sensor. Push down on this tab, wiggle it out. Take a straight blade screwdriver, loosen up this clamp right here. It should be good. You can push that snorkel off right there. It has all these clips holding the top of the air box off. I'm just going to take the top off. And this last one over here, it's kind of tricky to get to. Pull the dipstick out of the way. And then just grab the air box, pull the air filter out. I'm going to take these two bolts out. What you need is a 10 millimeter socket, extension, and an electric ratchet. You can use a regular ratchet if you don't have an electric one or an air powered one. Loosen them up, take them out. Now I just grab the air box, slide it up. This wire is on this little grummet right here, just try to slide that out. Just try to slide this off. All right, take that off and you can just slide this out of the way.

For this job that we're doing, you don't necessarily have to have the coolant drained or the coolant hoses off, but it's easier to see with the camera so we're going to leave that stuff off. Just keep in mind, you don't have to do all that to get to this position.

I'm going to take a 16 millimeter socket and a ratchet, and I want it on tightening. I'm going to go down here and get on the tensioner right there. You could use a serpentine belt tool as well. And then I can loosen up the belt, just like that. That's how it looks from underneath. With that loosened up, I can grab the belt and slide it off the crank, and then slide it off the AC compressor.

I'm going to take this serpentine belt off. What I'm going to need is a hex key. This happens to be a five millimeter hex key, and I'm going to use this 16 millimeter socket and a ratchet. Put the ratchet on tighten, and then right here on the tensioner is a little area you can put the socket, and then you're going to tighten it like you're tightening a bolt. That's going to loosen up the tension on the belt. We can take this hex key and slide it in that position. That's going to lock the tensioner. Let that go, then you can grab the belt, slide it off the idler, slide it off the alternator right there. We can pull our socket away, pull it off the water pump, off the tensioner, off the crank and off the power steering pump, just like that.

I'm going to take a 16 millimeter socket and a ratchet, and we'll take this bolt out right here. Loosen it up. Loosen that up, slide that bolt out. I'm going to loosen up on this bolt right at the base of the alternator. I'm going to use a 16 millimeter socket, extension and a ratchet. If the tensioner is in your way, make sure you put the pin through right there just to hold the tensioner. Loosen up. Loosen this up. So I'm not going to take this bolt out completely yet, I'm going to give it a couple threads and I'm actually going to take a hammer and give it a couple taps on the bolt. There is a bushing that threaded on the back side of the alternator that slides in. So right now, the alternator's kind of hard to wiggle out. You can try to wiggle it out, but if you give it a couple taps it'll be easier.

Just watch the radiator, you don't want to damage the radiator. It loosened it up a little bit. Pull this bolt out. Right now, just try to slide the alternator out. Just wiggle it back and forth a little bit. All right, that came loose. Now on the back side, I have to disconnect the connector. There's a connector right here. Disconnect that connector. And then this positive terminal right here, disconnect that. I'm just going to use a 17 millimeter wrench, loosen this up. Definitely want to make sure you have the battery disconnected when you're doing this, otherwise you're going to arc out. Pull that off, set it aside. Set the wire aside. Then there's a little snorkel right here attached to the alternator, we got to disconnect that, just slide up just like that. And then you can grab it, slide it out.

Here's the old part. Here's the new alternator from 1AAuto.com. It's got the same configuration, same mounting points, same pulley design. On the back side, it's got the same terminal connector. Same terminal. It has this same snorkel intake. You can just take this part off, throw it away. Get yours at 1AAuto.com and you can do it yourself.

So make sure you take that cap off right there. That's where the airflow comes in. If you don't have that, then you can leave that cap on. The alternator comes with a nut right here. I am going to remove that. I'm going to reuse the old one because it has this nice plastic extension on it. It makes it a little bit easier to tighten down. Slide the alternator in position.

And first, we're going to connect the positive terminal. Slide that over the terminal. Take the nut, get that started. My 17 millimeter wrench, just snug this up not too tight. You really don't want to over tighten this. All right, just snug. Make sure if you wiggle it, it doesn't come loose. Take the connector, plug the connector back in, just like that. Now, we'll put this snorkel on down here, and that's good just like that. Now, we'll line up the lower alternator bolt. I might have to wiggle this a little bit. Then take the top bolt, go through the pulley. Now, there is a little nub on the pulley that's going to line up with that little slot there. Oops, this has got to get lined up here first. I'll get this started. I'll take my 16 millimeter socket, extension ... I'm using an electric ratchet. You can use a regular ratchet if you don't have one. I'm just going to snug them up first, and then torque them. Now, I'll use a torque wrench and I'm going to torque these bolts to 34 pounds.

We're take the belt, slide it over the crank pulley down below. And then, with this other side, go over the power steering pump pulley over there. And then it's going to come around on the tensioner side, on the tensioner pulley just like that. It'll go over the water pump. It will go over the alternator over here, just like this. And then we want to go below the idler pulley. Now, we're going to have to put the socket and the ratchet on the tensioner and relieve some of the tension to get that all the way on. So I'm going to take the 16 millimeter socket and the ratchet, and then we need to have this on tighten. So we're going to loosen the tension on this, slide the belt underneath there. Make sure that's all lined up. When that's all lined up, then I can pull this pin out of the tensioner and let it go. Double check your belt. Go around all the pulleys, make sure it didn't pop off down near the power steering pump or the alternator. It looks good.

It's going to be a little bit easier to install the belt from underneath, so we're going to do that. Just take the belt, slide it over the AC compressor, and then slide it over the pulley for the tensioner, and then over the crank pulley. Make sure these are all lined up and that's good, just like that. Make sure those are good. Take a 16 millimeter socket and a ratchet, slide it into the tensioner. Relieve the pressure, and then slide this pin out. Or if you used a hex key, pull that hex key out. Double check that. It looks like everything's lined up. We're good to go.

So these have to go on together. Just slide this in position. Once you get this close, I'm going to start to tighten up the fan. Now, these fan blades are ... The fan clutch is reverse thread, so it's almost like you're going to be loosening it. There's really no easy way to do this, just do it carefully. Once you get it started, it's a little bit easier. Make sure the fan shroud is in properly. That's good. All right, if you have the ability to torque this nut for the fan, you're going to torque that between 22 and 29 foot pounds. I don't really have that ability, so I'm just going to put this tool on there and just give it a little tap. That should be good. Right here is the push pin. It's going to go back in here. Slide that in position, and lock it down. And on this side, we're going to put this screw right here. Then I'm going to use a T25 and a electric ratchet, tighten this down, just snug. I'll position this wiring harness right here, and we'll plug the connector in right here. Lock that in place.

Now, we're just going to slide this side of the lower air box in here. Yours may have something that this connects to. This vehicle doesn't. It just slides in position, and then this lower part slides there. And make sure these holes are lined up. Take these two bolts, get these started. Take a 10 millimeter socket and a ratchet and tighten these down. I'm using an electric ratchet. If you don't have an electric ratchet, just use a manual one. Take the air filter, reinstall it. Now, take the top part of the air box and slide it onto the snorkel first, just like that. And then, there's all these clips. Take these clips, lock this part down. Connect the mass airflow sensor and the air flow meter. I'm going to slide this clamp right here, take a straight blade screwdriver and tighten it down. Just snug, not too tight. Give it a shake, make sure it's good. Take this piece, slide this into the air box just like that. And there's retainers right here. Take those, push pins and lock them down.

Then we can take the negative side, connect the negative side. Take the same 10 millimeter socket and ratchet, tighten it up. That's good. At this point, if you had that cover, you're going to want to put the cover back where it goes.

Thanks for watching. If you want the parts to do it yourself, check out 1AAuto.com, the place for DIY auto repair.

Tools needed for replacement:

    General Tools

  • Hammer

  • Hex Wrenches

  • 5mm Hex Wrench

  • Pliers, Cutters & misc Wrenches

  • Side Cutters

  • Ratchets & Related

  • Socket Extensions
  • Torque Wrench
  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 16mm Socket
  • 17mm Socket
  • 10mm Socket

  • Specialty Tools

  • Trim Tool Set
  • Fan Clutch Wrench

  • Star Drivers & Sockets

  • T25 Socket
  • T20 Socket

  • Wrenches - Metric

  • 17mm Wrench

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