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2003 745i NEED HELP WITH ALTERNATOR REPLACEMENT

28K views 32 replies 14 participants last post by  Rick in Yuma 
#1 ·
Hey Everyone,

Soooo, my alternator seized up over this weekend. I've seen a few write ups about replacing the gasket for the alternator mount, but I haven't seen anything detailed regarding replacement of the actual alternator. I already bought the replacement alternator, and im pretty much ready to do the work but my main concern is removing things that really dont need to be removed. I reached behind the alternator and was able to find the 2 bolts that mount the pulley towards the bottom half of the alternator and it really appears that, that portion may be the only challenging piece.

Now knowing that my repair knowledge when concerning this car is fairly limited, I am very ready for the posibility that I am sadly mistaken lol.

Can anyone give me some advice on this repair?

What are the tools I'm going to need (for the bolts on the back of the alternator)?

Socket wrench? extension pieces? wrench? mm's?
Any special instructions?

What am I going to need to remove?(heard stablizer bar needs to be dropped and suported)

How long is this going to take?

Any write ups that may have some photos?

Anyone who can help or provide any type of insight will be greatly appreciated. Sad moment in my life right now lol. basically been riding my bike everyday to work and being on a cold freeway at 7am in a collared shirt slapping against your neck is no fun lol.
 
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#5 ·
:rofl: I saw that also. Sorry I don't think you really have to remove it :eek::dunno::)
 
#6 ·
Yeah Expo, seems like its a do-able job. Good luck on your repair! Figured I can take a weekend to do a job that would ordinarily cost 1300 bucks.
Thanks for the link Rookie!! I really appreciate it. Hopefully the bolts behind the alternator won't be real difficult to get to. Gonna be taking a lot of pictures so hopefully I'll have a decent write up for this site!!
 
#12 ·
Hey everyone,

Alright so this is where i'm at, at this point. Alternator is out and the replacement I bought was an aircooled alternator as per my cars factory specs (that's what BMW said after looking up my VIN & ReaOEM). I pull out the alternator and it's a water cooled alternator!!?? Now, I'm really concerned. Are the parts interchangable like that? Does this mean I'm going to need to remove more things?? looks like the mounting points are completely off on the aircooled... Is this normal? Any help is much appreciated. Thanks again
 
#14 ·
I'm sure since i've gotten this far, I can get the rest done. I really appreciate the offer though. I'm just confused as to why everybody says that my cars alternator should be air cooled and it turns out that it's water cooled. Could my engine have been swapped, did they completely botch the first replacement and put on the wrong one? The mounts are completely different for what it looks like... I'm in definite need of some clarification as to why the discrepency is there..
 
#16 ·
LOL fantastic:dunno: !! well back to the automotive stores for a replacement then. worst part about it is that I need put everything back together now only to have to remove it all again next week. Thank you for everyones input and help. F@#K!!!!:mad:
 
#20 ·
Well my next step us to repair the one I have. I really don't want to spend 700 bucks on another alternator so I'm basically on the hunt for the appropriate bearings needed as BMW no longer makes it lol (how fitting). So if anyone knows where they have them or can point me in the right direction, I would greatly appreciate it. I do have another vehicle but it's a motorcycle and luckily it's been warm here in southern California. But I'd really like to be comfortable out on the road and my AC suits me just fine lol
 
#21 ·
Honestly brotha all alternators for our cars are rebuilds no matter where you go! Here was my logic on buying mine when i needed to replace mine! 1. dealer sold them but it is a rebuild for $1,000-$1,200 with 2 year warranty 2. Autozone sold them as well rebuilds with lifetime warranty for $500 & change with core! If you weigh out options your better off with autozones! in my opinion anyways & if your doing job yourself!!!:thumbup::thumbup::thumbup:
 
#22 ·
i was going to get one from autozone my self but after reading few threads about it not being bosh but duralast brand i changed my mind....one guy had to change the alternator 3 times until he got a good one from autozone...other guy mentioned the ones from autozone have parts from china and since they are rebuilt they dont get rebuilt like bosh oem bmw ones....i think lifetime warranty is there because of lower quality components used in the rebuilt and they don't replace every component like lets say if you buy a bosh one....
only good thing is i only had to pay 700 for brand new oem bosh from bmw dealer instead of 1130+tax because the guy ordered air cooled one and my girlfriend picked it up brought it home and i was like what the hell is this???? air cooled one go for 680 from dealer...installed it last week and car runs like champ... i got the 180amp one but i still don't get why are they so expensive since they changed to air cooled ones in 2004 if iam correct??
 
#23 ·
Yeah I understand where ya coming from as far as reliability ! First one I got crapped out & I knew it would! It looked cheaply ! Took it back & got a Bosch rebuild! & everything is A ok a year & a half installed now! & now a days everything is made in china!!! It may say Bosch oem but more likely it's made in china! Looks at our car BMW's name alone stands beyond most! But look at the problems they come with!!!
 
#25 ·
Alright lol... So I know this is a bit late but I finally finished the alternator replacement for my car. Even though I was pretty broke the last few paychecks I pony'd up and mad a small sacrifice to not have to see my car sitting there collecting dust. Installed the alternator. I was pretty rough in the begining with regards to actually getting to the bolts I needed to get to, and after about 3 hours of searching for enough light, removing bolts in the most odd places, many drops of oil and collant to the face, and 2 trips to pep boys for the right tools, the alternator was out and ready to be rebuilt.

I took it to Valley Alternators in Winnetka, off of Saticoy and Winnetka in the San Fernando Valley. The owner was really curteous and turn a bad situation into somthing awesome. He was able to rebuild my 180AMP Bosch alternator for 300 minus giving me 50 bucks for the alternator that I bought previous (air cooled, and wrong). I spent more on it, but I was happy to get rid of it because I had no use for it.

For anyone who says that the fan shrowd doesn't need to be removed, I have no idea how you would get that alternator out of there without removing it, it was a tight fit even with it off. I didnt completely remove the active stabilizer bar, I just removed the left side and tied it up to one of the other componants just to make sure it didnt go down too far. Just like everyone says, the 2 bolts attached to the bottom of the alterator that hod the pulley place was the absolute worst part of this job. ratchet wrenches helped a lot, for the most part once they were loosened, I did it with my fingers so it was fairly simple (if you got fat fingers there's no way though).

Felt good being able to save like a 1600 off what the dealer quoted me and even 1k less than what the indy shop quoted me. I wont say any names because they've taken care of me in the past and maybe they just don't specialize in that type of repair and quoted me a price that they were comfortable with.

Either way, job done. It was an easy fix now that I look back on it. Thinking I'm ready to tackle some more challenging fixes at this point. maybe once I get a little more money i'll take care of the left side timing cover gasket (have a small seap).

Couldn't have done any of that stuff without all your help. It's awesome that everyone helps eachother on here and lends their expert advice. I am forever thankfull because 1600 dollars is something I didnt have.

Thanks again to everyone.
 
#26 ·
Replaced Mine today also

I replaced mine today also but it was on a 2004 745i and it was air cooled. I found a great deal at BMAParts on a Valeo unit (same brand as my original alternator) for $255.00. I used coupon code specE30 to save 5% plus free shipping. The alternator was brand new and not rebuilt. No core charge either. I also bought new belts. The only problem I had was that I broke the belt tensioner so had to order another one for $40.

Why I have the fan shroud out and everything opened up I am going to replace the water pump and all hoses.:thumbup:
 
#27 ·
Nice!! Yeah, once I took the off the fan and plastics, I noticed that water pump, oil pump and some of the other pesky things that fail over the years are fairly easy to get to on this car. You're probably doing the right thing by getting it out of the way early. Wish I could too, but I'm broker than a joke as of late lol. Good luck with the repairs!!
 
#31 ·
Hello i just bought me a BMW 745 i its a 2004 nd car wont turn on so i bought a new battery for it and now i ran it all day and now it wont turn on again so i think its the Alternarator so i just order one for 92$ hear online but now im reading all this comments how do i kno if i got the wright one can anyone help me plz ??
 
#33 · (Edited)
Put the last seven digits of the Vin number of your car into this site it will tell you exactly what you have. www.realoem.com also if you inspect your current vehicle. Look and see if the alternator currently has slots for air in it. Then it's air cooled. If it's built into a housing then it's watercooled. Unless you bought a used alternator for $92 you probably bought an air cooled. Water cooled alternators are very expensive. Rebuilt good price is around $650. The dealer cost is about 1200.

Here's what watercooled looks like.

http://www.autohausaz.com/search/pn...SKU_Mercedes&gclid=CJbu4s-Nl88CFQx9fgodEJ0MkA

Here's what the air cooled one looks like.

http://www.eeuroparts.com/Parts/63230/Alternator-180a-Rebuilt-12317540992/
 
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