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How to Replace Coolant Reservoir 01-05 BMW 325Xi

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How to Replace Coolant Reservoir 01-05 BMW 325Xi

Created on: 2019-08-13

Learn how to replace the coolant reservoir on your 01-05 BMW 3 series vehicle. 1A Auto shows you how in this step by step video!

  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 wiring from the retaining tab
    • Remove the air filter box
  3. step 3 :Removing the Coolant Reservoir
    • Remove the coolant reservoir cap
    • Open the radiator drain at the bottom driver side of the radiator to drain the coolant
    • Release the retaining clips to disconnect the upper radiator hose from the coolant reservoir and radiator
    • Remove the T20 radiator screw above the coolant reservoir
    • Remove the T20 coolant reservoir screw
    • Pry up the retaining clip to disconnect the coolant hose from the reservoir. More coolant will drain out, have a drain pan ready
    • Pull the reservoir retaining lever towards the center of the vehicle
    • Lift the reservoir straight up to remove it
    • Disconnect the coolant level sensor electrical connector
  4. step 4 :Installing the Coolant Reservoir
    • Reconnect the coolant level sensor electrical connector
    • Lower the coolant reservoir onto the connections and lock the retainer
    • Reconnect the hose to the reservoir and lock the retainer
    • Install the T20 reservoir screw
    • Install the T20 radiator screw
    • Install the upper radiator hose onto the thermostat housing and lock the retainer
    • Install the upper radiator hose onto the radiator and coolant reservoir and lock the retainers
  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
  7. step 7 :Refilling the Coolant
    • Use coolant specified by the vehicle manual
    • Fill the coolant reservoir
    • Remove the bleeder screw adjacent to the reservoir opening
    • Fill the reservoir until coolant flows out the bleeder opening
    • Reinstall the bleeder screw
    • Adjust the coolant level as necessary
    • Run the engine with the heat on to bleed the system
    • Adjust the coolant level as necessary

Tools needed for replacement

  • General Tools



    Drain Pan

  • Pliers, Cutters & misc Wrenches

    Side Cutters

  • Ratchets & Related

    Socket Extensions


  • Screwdrivers & Related

    Flat Blade Screwdriver

  • Sockets - Metric

    10mm Socket

    22mm Socket

  • Specialty Tools

    Trim Tool Set

    Fan Clutch Wrench

  • Star Drivers & Sockets

    T25 Socket

    T20 Socket

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

With the trunk open, over 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, just going to use some side cutters to get this center pin, pull that up, and then slide it out. Be careful not to cut that. 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 the 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 tool from, take this push clip out, pull that out.

All right, now that is loose. But what 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 with many different sizes. This happens to be the 32 millimeter. That's going to slide on there, and then we slide this on. 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 reverse 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. 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 we can slide this right up, 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. That should be good. Push that snorkel off, right there. And there's 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. You just grab the air box. Pull the air filter out.

I'm going to take these two bolts out. I'm going to use 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'll just grab the air box, just slide it up. This wire is on this little grommet right here, just try to slide that out. Just try to slide this off. All right, take that off. You can just slide this out of the way.

I'm going to pull this fill cap off before we drain the coolant. Make sure the engine is cold. You don't want to take this off while the engine is hot or you're going to get splashed in the face with coolant. Pull that off, and now we can raise the vehicle and drain the coolant.

Underneath the vehicle there may be a cover right here. You're going to have to remove it. There should be some fasteners there, there, and there, and there, and then also back there. This vehicle doesn't have it so we're just going to start right here. I need to loosen up this drain right here. This radiator is not the original radiator so I believe you're going to have a different size socket to use. If you have the OEM radiator for this one it's a 22 millimeter socket. I'm going to use an extension and a ratchet. Loosen this up. Make sure you put a drain bucket underneath.

I'm just going to remove this, and there we go. That coolant looks nasty.

To help the coolant drain out a little faster. I'm going to open this bleeder screw right here. Just use a straight blade screwdriver. Loosen this up.

All right, I'm going to test this coolant. Let's see how it does. What we do is suck up some of this coolant. It's going to test the level of protection you have. So with the tool level this is actually way out of spec. It should be right there around negative 35 degrees Fahrenheit. Negative 32 is ideal. So this is way out of spec, so it's a good thing we're going to drain and fill this coolant.

Now we want to remove this side from the radiator. I'm just going to take a straight blade screwdriver, slide up under this retaining clip right there, and then there's also one right here, just like that. Now I can just grab this hose and just wiggle it a little bit. All right, pry that off. That's good. Now I'll take the screwdriver, just take this hose off completely, and slide the clip out. Just wiggle this back and forth, pull it out.

There's that screw right here. I'm going to use a T20 socket extension and a ratchet. Take that screw out. Now I can move the radiator out a little bit, and we're going to take this screw out. Now if you weren't taking this section of the radiator off, and you were just doing the reservoir, you can loosen up the bolts on the headlight, move the headlight forward, then you might be able to gain access to that screw right there. I'm going to use a T20 on this screw, take this one out. Pull that screw out.

So I'm going to pull this coolant hose off. Just use a straight blade screwdriver or a pick. Pull up on the retainer clip and then just wiggle it off, there we go. Let that out. A lot more coolant came out. I'm sure you still have your drain bucket underneath there.

Now from underneath the vehicle ... you don't necessarily have to be from underneath the vehicle. I just wanted to show you how this worked. There's a little lever right here that you can actually grab from above the vehicle, and you just pull it towards the center of the vehicle, just like that, and that releases the lock that holds that in.

So now that clip is released. Now we're just going to grab the tank and slide it up. The coolant sensor is still down there. We'll have to disconnect that, but I'm just going to grab the tank and just pry it straight up. Be careful. You don't want to rock it back and forth too much because you could break other plastic. Just pull it up just like that. You're going to have some more coolant come out, just slide it up. You slide it up. I can disconnect the connector right here. Push down the tab, pull it out like that.

Here's the old reservoir. Here's the new reservoir from It's machined the same way, has the same fittings for the coolant pipes, same fittings on the bottom as well, same retainer. Comes with the level sensor on the top. The top part is machined the same way for the coolant cap, and the same fitting. Get yours at and you'll be ready to rock and roll.

Now I'll take the new reservoir and I'll plug this connector in right here for the level sensor, and then slide this in position, and just push it down slightly and lock it in place. All right, that's good. Lock it down.

Take this hose, line this up, and lock it in place just like that.

Take this screw right here. It's just easier to put this on before I put the hose on. Get that started. You take a T25 extension and a socket. Tighten this down. Just snug. It is in plastic, so be careful.

All right, take this pipe, this upper hose, and just line that up right there. Lock it in place. And then over here, line this up over here and just wiggle it a little bit. Lock that in place. Make sure this reservoir is locked in too. That's good.

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 there's a push pin. That's going to go back in here, slide that in position and lock it down. On this side we're going to put this screw right here and I'm going to use a T25 and a electric ratchet. Tighten this down just snug. I'll put 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 makes 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 racket. If you don't have an electric ratchet just use a manual one.

Take the air filter. Reinstall it. I'll 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, or 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, 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. When adding the coolant we're going to use a funnel, and you want to make sure you add the appropriate type of coolant. You can check your owner's manual. There is BMW specific coolant. Generally it's blue coolant, so we're going to fill up the reservoir. We're going to take this bleeder screw out. Just use a straight blade screwdriver or a Phillips head. Just move that funnel.

You could probably just loosen this up a little bit, or you can take it all the way out, just like that. Set it aside. You want to fill this all the way up to the top and have coolant come bubbling out of the bleeder hole. Once it's coming out of there, we're going to reinstall the bleeder screw. It is plastic, so be careful. You don't want to strip this. Get this started again. Then close that bleeder screw, and then you're going to adjust the level in here. Now there is a little dipstick in here. When this is full this is going to be all the way at the top. Now you can check it right here. It shows where the min and the max is, so you want to adjust that accordingly. You can add coolant or take out coolant. You can use like a turkey baster, or some type of fluid pump, to suck the fluid out. Then you want to let it run.

You want to leave the heat on. When you leave the heat on, if you don't have heat, you're going to want to crack this open a little bit and just make sure you get some of the coolant out. It's probably a good idea to shut the engine off, let it cool down, and readjust your coolant.

When you're done, when the fluid level's at the appropriate level, take the cap, put it back on.

Make sure you monitor your temp gauge while you're running the vehicle. If you run the vehicle for about 10 minutes the temp gauge should go right in the middle there. If it starts going to the red, shut the vehicle off and start over. Bleed the system again.

Thanks for watching. Visit for quality auto parts shipped to your door, the place for DIY auto repair. And if you enjoyed this video, please click the subscribe button.

Tools needed for replacement:

    General Tools

  • Funnel
  • Pick
  • Drain Pan

  • Pliers, Cutters & misc Wrenches

  • Side Cutters

  • Ratchets & Related

  • Socket Extensions
  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 10mm Socket
  • 22mm Socket

  • Specialty Tools

  • Trim Tool Set
  • Fan Clutch Wrench

  • Star Drivers & Sockets

  • T25 Socket
  • T20 Socket

1999 - 2000  BMW  328i
2001 - 2006  BMW  X5
2006 - 2008  BMW  X3
2004 - 2005  BMW  X3
2001 - 2005  BMW  330Xi
2001 - 2005  BMW  330i
2001 - 2005  BMW  330Ci
2001 - 2005  BMW  325Xi
2001 - 2005  BMW  325i
2000 - 2000  BMW  328Ci
2000 - 2000  BMW  323Ci
2001 - 2006  BMW  325Ci
1999 - 2000  BMW  323i

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