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Old 03-14-2019, 06:32 PM
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Maruzo Maruzo is offline
Join Date: Mar 2017
Location: Los Angeles
Posts: 196
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So I got up the courage and started working on the removal of the water-cooled alternator this week. Took me the better part of yesterday to complete the removal and reinstall.

Tools used:

8mm, 10mm sockets to remove the large plastic underbody dirt shield.

13mm socket to remove the frame that attaches the suspension pump.

10mm socket to remove the negative terminal from the battery.

long nose plier to remove the 4 clips holding the air intake housing.

flat blade screw driver to pop up the clip holding the intake air box, as well as the various radiator hoses.

32mm wrench and clutch holder to remove the clutch fan bolt.

13mm socket to remove the tensioner pulley.

50mm torx bit to remove the 2 pulleys.

10mm socket to remove the 6 bolts holding the alternator to its housing.

17mm socket to remove the negative cable to the alternator.

Fun times. Taking out the airbox and intake was a breeze and took around 10 minutes. Removing the water hoses was pretty straightforward as well. The next step, however, is where I got stuck for 2 hours: removing the 32mm clutch fan bolt.

I used a combination of hammering on the bolt, blasting the joint slit with lubricants, and the bmw fan clutch tool (clutch holder and 32mm wrench). The force required to break the bolt lock is very considerable!

Once the bolt is out (swing the wrench righty loosey and lefty tighty for this bolt), I unclipped 2 wire connectors to the left of the fan shroud, then removed the fan along with the shroud.

The rest of the steps are time consuming but uneventful. Took out the tensioner pulley, 3 x13mm bolts, 2X 50mm torx on the pulley, removed the serpentine belt, and finally access to the alternator!

The steps are very similar to a regular 540i/ 740i with m62, except the design of the radiator are a little different.

I'm not sure if the 4.6is has the exact same water hose and radiator design as a 2001~2003 4.4i. Can anyone confirm?

Anyway, I do have a few questions that I hope the E53 gurus here can answer for me:

1. Should I be concerned that my original coolant fluid is a light orange color? It reminds me of a rust color (please see attached). Very different from your regular neon green/ or bmw light blue.

2. The clutch fan has been on constantly since the alternator replacement. Is this normal? I remember it was hardly ever on before the replacement.

3. My friend with some auto repair experience helped me with installing the tensioner pulley as well as tightning the belt tension (1/2" play when you push on the belt). I see him adjusting the 2 13mm bolts on top of the pulley mechanism and that seemed to do the trick. Can anyone elaborate on the correct procedure to tension the serpentine belt?

4. adding coolant. The blue plastic valve on the bottom right of the plastic radiaor housing pretty much shattered upon impact with a flat blade screw driver when I attempted to remove it to drain the coolant. Half of the valve remain stuck on the housing so it's still sealed, I think. I don't know how to remove the rest without damaging the thread on the radiator, so I tried to seal it better with bunch of silicon gulking and then left it alone. I will probably need to revisit this situation, depending on when I need to drain / flush the coolant or when the rest of the valve decides to give up!

Most of the coolant that drained from the system came out when I pull out the hose that connected to the top of alternator housing. I must have drained at least 6 quarts of that light orange colored fluid.

Do you guys think it's correct to add the fluid into the expansion tank until the red stick floats up?

Do I release the bleeder valve next to the expansion cap half way while I add the fluid? Or do I release the valve and then start the car, and wait for the air bubbles to show up?

The first time I added fluids yesterday, (using bmw light blue coolant), I added slightly more than 1 gallon, then I started the car. Low coolant warning showed up so I switched off and added another 1/2 gallon.

The low coolant warning came up again today, So I added another 1/4 gallons with the bleeder valve open 1/2 way. The red stick floated up again, so I stopped right there.

So far i've added 1 3/4 gallon of bmw coolant. I will continue to monitor the level but right now I don't know if i've added too much or not.

I did not see any coolant leak yesterday nor today, so that's a plus.

Please kindly provide the correct procedure on filling coolant fluids, as well as any bleeding procedure that applies!

5. Charging. I have a cigarette bluetooth adapter that tells battery voltage. The voltage was a dismal 12.2 v or lower before the replacement. The sound system would cut off and all the lights would dim, so on Tuesday while driving to work I turned off all accessories: a/c, radio, daytime running light, etc and crossed my fingered as I navigated the scary last 10 miles on my way to work.

After the replacement, I tested the charge under load today. Turned on the a/c, the radio, and even the dvr that's connected to the cigarette lighter under the glovebox. The voltage was a constant 14.1+V.

Does this mean my new alternator is working correctly? What's the best way to test the functionality of an alternator?

Will attempt to add some work photos later on today.

Much obliged to any comments/ suggestions!

Attached Images
2003 X5 4.6is Estoril Blue, acquired March 2018
2006 330i Sports 6 MT Sparkling Graphite daily driver
2010 535xi 6 MT Barbera Red

Last edited by Maruzo; 03-14-2019 at 07:19 PM.
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