DIY : E92 M3 Alternator Replace

[Route 16]

Originally Posted by JPacy

I've been having some battery issues for a few weeks now. Every now and again I get in the car and it gives me the battery discharge warning. It seems to very with the cold weather which has been an issue since I am in Philly. One day its 60 then next thing you know its 10. Anyway today I was driving on my way home from work and started to get all sorts of messages on my dash, immediately thought it was the battery. Well then everything just dies out, and I sit for 25 mins waiting for a jump but out of the blue it started up without needing it..... Worried to drive it as I don't want to be stranded. I went out and checked the battery and the alternator and both seem to be at the right numbers(12.3V and 14.5V respectfully), also the car started up without a hitch. I found this video that was really helpful, no need to have a voltmeter. Apparently the car has that function built in. Anyway I am not sure what to check next. I have read about the plug-in contact of the battery positive cable on the front power distributor being loose in the E92 M3, but not sure if that the culprit or not. Any recommendations?

Voltage display on dashboard video:

nice trick

[dty3]

jpacy, the same thing happened to me, the alternator would work fine then i would get increased battery discharge. if you can do that check when you get that message, or just take a voltmeter to confirm...i have changed my alternator and no issues to date

[Budge]

Is the bottom screw on the alternator much longer than the top one? Also, I cannot get the alternator out. It wiggles up and down a bit, but will not slide forward. Also, for it to come forward, the tensioner pulley would have to come off. So which direction should I be pulling the alternator after I get the bolts out?

[Budge]

Originally Posted by haseeb1898

Thanks so much for this guide.

When I get the bolts out and it comes time to wiggle the alternator out, is it supposed to be ridiculously hard to get out? I've been trying to get it out for the past two days by wiggling it or using a 2x4 to pry it. I've had about ten different people try to get it out but it seems to just be pivoting around where the bottom bolt goes in (I've already taken out both bolts). It's really stuck in there.

I'm having the exact same problem. It pivots up and down where the bottom bolt came out. I have no idea how to get it loose.

[Budge]

I'm convinced that NO ONE is participating in this thread anymore. But I'm going to give some advice anyway so that the next person won't have to struggle the way I have.

The reason why the alternator in the M3 is held in so incredibly tight at the bottom is because there is a bushing that compresses when the bottom screw is tightened. It took a pry bar and rocking the the alternator back and forth TO THE RIGHT for a long time before it finally came out. As far as I know, there is no way to loosen the bushing while in the vehicle.

But then, it's just as hard to put the alternator back if the bushing on the new alternator is toward the center. You need to knock that bushing outward until it's flush. Then the alternator will slide back in and the bushing will pull itself tight when you tighten the bottom bolt.

I really hope this helps someone else. I appreciate that y'all took the time to write a walk-through.

[0_to_60]

Originally Posted by Budge

I'm convinced that NO ONE is participating in this thread anymore. But I'm going to give some advice anyway so that the next person won't have to struggle the way I have.

The reason why the alternator in the M3 is held in so incredibly tight at the bottom is because there is a bushing that compresses when the bottom screw is tightened. It took a pry bar and rocking the the alternator back and forth TO THE RIGHT for a long time before it finally came out. As far as I know, there is no way to loosen the bushing while in the vehicle.

But then, it's just as hard to put the alternator back if the bushing on the new alternator is toward the center. You need to knock that bushing outward until it's flush. Then the alternator will slide back in and the bushing will pull itself tight when you tighten the bottom bolt.

I really hope this helps someone else. I appreciate that y'all took the time to write a walk-through.

There is no bushing on the alternator, it is literally metal, there is no way you can push anything. I know exactly what you are talking about, i have seen it on other vehicles, on power steering pumps.

[Budge]

Originally Posted by 0_to_60

There is no bushing on the alternator, it is literally metal, there is no way you can push anything. I know exactly what you are talking about, i have seen it on other vehicles, on power steering pumps.

Maybe I'm using the wrong term when I wrote "bushing", but there is definitely a movable metal nut that is lagged tight when you secure the bottom bolt of the alternator. That nut sits tightly within a fitted slot. I put the bottom rear portion of the alternator in a vice to squeeze that nut (or bushing) back into that slot. THEN the alternator fell back into place with no effort at all. I'm 100% positive about this. The original alternator in my car was made by Valeo (BMW OEM).

[0_to_60]

Originally Posted by Budge

Maybe I'm using the wrong term when I wrote "bushing", but there is definitely a movable metal nut that is lagged tight when you secure the bottom bolt of the alternator. That nut sits tightly within a fitted slot. I put the bottom rear portion of the alternator in a vice to squeeze that nut (or bushing) back into that slot. THEN the alternator fell back into place with no effort at all. I'm 100% positive about this. The original alternator in my car was made by Valeo (BMW OEM).

interesting, when I worked on my car months ago, I initially thought about that metal nut. I tried using pliers, vice grips, hammering and it didnt budge. As i looked closer, their was nothing on my unit that can be pushed in. The metal nut was located on the outside frame of the alternator housing, so if i was going to push it it will only hit metal to metal. It wasn't physically possible.

[Budge]

Originally Posted by 0_to_60

interesting, when I worked on my car months ago, I initially thought about that metal nut. I tried using pliers, vice grips, hammering and it didnt budge. As i looked closer, their was nothing on my unit that can be pushed in. The metal nut was located on the outside frame of the alternator housing, so if i was going to push it it will only hit metal to metal. It wasn't physically possible.

So that nut is a hexagon on the back side and circular toward the front. That circular part gets lagged through the hole when tightening the bolt. When I removed the original alternator (which took hours...no days), that circular portion was protruding forward through the hole by about 1/4 inch. I used my vice to push it back it because nothing else worked.

In retrospect, I thing I have a new way to easily remove the alternator if one gets stuck like mine. Find a short bolt that's the same size and insert it with a washer from the back side. As you tighten it, the nut should back out enough to easily release the alternator from it's mounting position. If that works (it should), people should send me some beer money for how much time I just saved them. Seriously!

[bmwlover0725]

This write up was extremely helpful. I had a charging malfunction warning last week followed by a completely dead alternator a couple of days later. If I might add one thing to this - it’s to keep an eye out for the small expansion take hose that branches off of the upper radiator hose. I was tired and got lazy with this part while I was violently shoving the fan shroud back in and broke it as a result. Thankfully I was able to half ass it with JB Weld until the new part comes, but I wish that I was more careful.

Thanks again for the DIY. This was perfect.

[gazosnic]

I can't get the alternator out either... and afraid to put a crowbar against anything cause seems there is a lot of breakable items near there. Any other tips? How the hell does this thing come out?

[RedCardinal]

Originally Posted by gazosnic

I can't get the alternator out either... and afraid to put a crowbar against anything cause seems there is a lot of breakable items near there. Any other tips? How the hell does this thing come out?

Hey, I'm about to order the parts to do this (the 180 amp Valeo and the two aluminum bolts) and look forward to giving it a shot next week.

However, as this is my only car, I was wondering if you'd share how you finally got the alternator out. I'm trying to be prepared so I don't have to leave it in my friend's driveway overnight because I can't get the thing out...

I had posted about this before but I replaced the battery and the problem went away. It's back now though so I figured the alternator is next.

Thanks in advance!

[gazosnic]

If anyone needs a OEM alternator to refurbish i'll sell my old one pretty cheap. Just PM me.

[msan]

This help?

https://www.newtis.info/tisv2/a/en/e...parts/1LoEP3cn

[RedCardinal]

Originally Posted by msan

This help?

https://www.newtis.info/tisv2/a/en/e...parts/1LoEP3cn

lol! Thanks for the post. Sure, that's helpful.

But I was asking about how the poster I had quoted finally got the thing out of the car. Evidently it can become stuck, as noted be several others in the thread.

I only have the one car. The more I learn now about issues I may come across while replacing the alternator, the less down time my car will have. Also as I said, I'll likely be doing this in someone's driveway, I live in a city and can't do it in my apartment's underground garage. I wouldn't want to leave it in my friend's driveway overnight - or longer! - if I can help it...

[codinge90]

Originally Posted by RedCardinal

Hey, I'm about to order the parts to do this (the 180 amp Valeo and the two aluminum bolts) and look forward to giving it a shot next week.

However, as this is my only car, I was wondering if you'd share how you finally got the alternator out. I'm trying to be prepared so I don't have to leave it in my friend's driveway overnight because I can't get the thing out...

I had posted about this before but I replaced the battery and the problem went away. It's back now though so I figured the alternator is next.

Thanks in advance!

I did my alternator twice a few months ago. First time I used an autozone one, threw and alternator code to returned it and got an oem one. First time it took like 5 hours second time took me 30 minutes. Hardest part is getting the actual alternator out. What you'll need to do is get some wd40 or something to lube up where the bolts slide into on top and bottom of the alternator, let it sit and literally use a crowbar and yank it out. Depending on how old the car is, it'll be budged in there. Mind took an actual crowbar to get it out, you really gotta pull and push until either the top or bottom slides out. Everything after is simple

[Budge]

Originally Posted by RedCardinal

I only have the one car. The more I learn now about issues I may come across while replacing the alternator, the less down time my car will have. Also as I said, I'll likely be doing this in someone's driveway, I live in a city and can't do it in my apartment's underground garage. I wouldn't want to leave it in my friend's driveway overnight - or longer! - if I can help it...

I wouldn't start that project if you're on a time limit. Like others have said, it will take a pry bar and a lot more muscle than you may be comfortable applying to other parts of the car. It took me several hours of frustration before I got up the nerve to pry as hard as I needed to while rocking the alternator back and forth.

Another piece of advice that I will offer is to take a flat piece of cardboard and tape it over your radiator to protect it from dings (or worse). Also, I would use tape or a towel to cover the sharp edges at the front of the engine bay. Otherwise, you will cut up your forearms no matter how careful you are.

[msan]

Originally Posted by RedCardinal

lol! Thanks for the post. Sure, that's helpful.

But I was asking about how the poster I had quoted finally got the thing out of the car. Evidently it can become stuck, as noted be several others in the thread.

I only have the one car. The more I learn now about issues I may come across while replacing the alternator, the less down time my car will have. Also as I said, I'll likely be doing this in someone's driveway, I live in a city and can't do it in my apartment's underground garage. I wouldn't want to leave it in my friend's driveway overnight - or longer! - if I can help it...

This guy did it in 10 mins

https://www.m3post.com/forums/showpo...22&postcount=2

[RedCardinal]

Originally Posted by Budge

I wouldn't start that project if you're on a time limit. Like others have said, it will take a pry bar and a lot more muscle than you may be comfortable applying to other parts of the car. It took me several hours of frustration before I got up the nerve to pry as hard as I needed to while rocking the alternator back and forth.

Another piece of advice that I will offer is to take a flat piece of cardboard and tape it over your radiator to protect it from dings (or worse). Also, I would use tape or a towel to cover the sharp edges at the front of the engine bay. Otherwise, you will cut up your forearms no matter how careful you are.

Thanks, those are very helpful tips and Ill certainly follow them.

[RedCardinal]

Originally Posted by msan

This guy did it in 10 mins

https://www.m3post.com/forums/showpo...22&postcount=2

Does he have the car on a lift, or is the video upside down.

[RedCardinal]

Originally Posted by codinge90

I did my alternator twice a few months ago. First time I used an autozone one, threw and alternator code to returned it and got an oem one. First time it took like 5 hours second time took me 30 minutes. Hardest part is getting the actual alternator out. What you'll need to do is get some wd40 or something to lube up where the bolts slide into on top and bottom of the alternator, let it sit and literally use a crowbar and yank it out. Depending on how old the car is, it'll be budged in there. Mind took an actual crowbar to get it out, you really gotta pull and push until either the top or bottom slides out. Everything after is simple

thanks for the tips. did you follow op's method of getting to it - remove air box and radiator fan?

thanks again.

[msan]

Originally Posted by RedCardinal

Does he have the car on a lift, or is the video upside down.

Probably On a lift. But this was the key info...

most important key is remove the Alternator's top bolt about quarter inch and remove the bottom bolt about half inch. And get a hammer and start hitting the bottom bolt like you are hammering a nail! There is the back part of this bolt has to move quarter inch while you are hammering! And you will see that alternator start getting loose. And then jiggle the alternator and see how loose it become. If it is not that loose hammer back again! Once it is loose remove regardless of order bottom or top bolt and put the alternator to the bottom of the engine tray!