First time 3 hours second time 30min

Hi Rogerkiu, hope you get to see this thread; just wondering if you could guide me on how to remove the electrical fan. What should I pay attention to so I do't break anything, etc. I need to replace the alternator, but having difficulty removing the electrical fan. It seems like stuck at the bottom. Can it be done from underneath without removing the fan?

Thanks,

Excellent DIY overview, but as one who is always analyzing short cuts, I did it my way, and it took less than an hour. I removed none of the items other than fan, shroud and idler pulley, not the whole unit, just the one idler to get belt off. It is a tight fit, so put a protective sheet of card board, or in my case, an old plastic sign which worked great. Since it is a tight fit to remove, you have to protect radiator fins and outside of water connection to alternator, and obviously the connectors, that is it. Also, rather than go through hassle of battery disconnection, just disconnect at engine connection which kills power to engine bay. Took me just about an hour, putting belt back on was the biggest hassle and took a few tries by just replacing idler pulley and leaving it for last and once belt was positioned, put a little leverage on it to align bolt to engine.

Good luck,

This is a great pictorial DIY:thumb up:. Props to the OP (yes, he missed the ground cable first removal, but IMHO, a minor transgression ;)).

My OE alternator failed in the most incredible way possible. It SEIZED completely :wtf:! In my entire lifetime of driving I have never experienced a completely seized alternator. Especially not one that gave any hint of shaft bearing issue noises.

My 2003/4.4 had about 92K miles on it.

After a short drive up to my local shopping center, I shut down and went in to shop. When I came out to try to start it, it would crank a very little and then dead stop. I thought that since my battery was an 7 year old factory battery, that I had a battery problem, so I walked to the nearby Walmart and bought a booster.

I attached the booster and then began to crank. It cranked and started then a moment later, smoke began coming from under the hood. I immediately shut down and wished that I had mounted a fire extinguisher in the vehicle (like I had in my other Bimmers), but no joy. I then looked inside the engine bay expecting there to be some sort of electrical fire going and my X going to be a char ball. When the smoke cleared I was able to see that the main serpentine belt had completely shredded and wrapped itself all over everything.

After unravelling the belt I attempted another start and the engine started normally and I was able to muscle the X the 6 miles home without P/S and get it into the garage with just a smudge over half on the temp gauge.

This is where I discovered that the alternator shaft was completely seized and seized so well that the serpentine belt tension was able to prevent the starter from cranking over the engine.

I took the alternator replacement as an opportunity to change ALL the original cooling system hoses all the way to the firewall as well as the heater control valve, water pump, thermostat, belt tensioners and belts.

If you have the budget available, this is a great time to tackle those other items as well. :dunno: :dunno:

I was thankful this failure happened near home and not on a far away road trip.

Next on my high mileage components list is the battery, fuel pump and plug coils.

PS: I have used a trickle charging battery maintainer on this X for the nearly 3 years that I have owned it and the 7 year old BMW OE battery continues to do well.

Be careful out there with high mileage components.

Mike

ALTERNATOR BEARING FREEZE
 

Interesting, like you, I never heard of bearing freeze unless it was noisy prior to, so I am shocked, just rebuilt my alternator and checked bearings for any hint of noise or excess friction, spun easily and quietly and I was debating whether to replace bearings or not since I had it split apart where a diode corroded lead was issue. Wish I had known about bearing freeze issue sooner, oh well, will keep an ear out for any signs of freeze. Thanks for posting this, news to me and I thought I heard of every problem with bimmers. Learn something new every day. As to battery note, yes, I have had several bimmers and batteries all lasted on average 7 years, unheard of in any of my other vehicles over the years, and I did not use trickle charge.

When I googled the problem, I think I only came up with two other BMW alternator seizures

http://www.xoutpost.com/bmw-sav-foru...i-driving.html

and

http://www.bimmerforums.com/forum/sh...-pulley-seized

I was disappointed that I was unable to open my seized alternator case (the torx heads stripped) to do a proper post mortem on the failure.

ALTERNATOR ISSUES
 

Thanks, with only two issues with bearings over all the forums, I feel a little better about not replacing my bearings when apart. Yes, I know about those nasty easy to strip out torx, very soft metal, and obviously, on purpose knowing BMW makes all their bucks on service more than selling cars. Use the best torx tool you can find, then use impact wrench pushing down as hard as you can, they come right out whereby it is difficult getting good bite by hand tool in my experience.

Impact wrench?

Are you aware that there are torque specs for almost EVERY fastener on a BMW?

BMW uses plastics/alloys/small fasteners to reduce overall vehicle weight, torque specs are a MUST for DIYers.

Yes, just use to remove, not put on, the locktight on those alternator torx are one shot to get out or they strip easily.