Teach me about alternators for the C5 A6...
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AudiWorld Member
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Isn't Valeo and Bosch the suppliers for Audi? The part on Amazon would be an official Bosch part that from Bosch's web site says is a fit for the 2002 A6 2.7T. I would only install it if it looked to be packaged from Bosch and not used/open box.
I just hate to wait like a week for something that should probably only take a couple hours if I had the part. Why the HELL don't the dealerships keep a couple of these kinds of things in stock?!
I just hate to wait like a week for something that should probably only take a couple hours if I had the part. Why the HELL don't the dealerships keep a couple of these kinds of things in stock?!
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Joined: Aug 2011
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From: Washington
Bosch Re manufactured alternators are the only Remans i will buy for these cars. I have tried Napa alternators and it gets old real fast on the 3rd bad one in a row, then they try to say its a problem with the car..even though I replaced it for bearing noise not a charging issue. The two do interchange no problem, they are physically the same looking, I dont even know what the difference is because on the outside its just a printed label is different.. I have used bosch in place of Valeo because they seem more available with no trouble, fit right in and operate the same.
Tech Guru
Joined: Oct 2002
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From: Olney, MD
Also, I'm replacing it for good measure since it's probably very old (164k now, bought the car at 95k, I've never replaced it, who knows before that) but the big issue was the surge to 16v for 10 second or so and the CLUNK and then limp mode (I think?) for the rest of the way home... car started again fine and transmission seemed to be fine, but I'm almost positive I'm running off reserve battery power only now (showing like 11 to 12 volt MAX). I'm confused why the alternator would have pushed me up to 16 volt before the system killed it to protect it from over voltage (?? maybe?) or it burned it's self out...
I have noticed the last two winters random times that it would dip down to 12v while at a stop light and then as soon as I got on the gas it would jump back to like 13.5 to 14v so maybe it was on it's last legs...
Only thing I can think is the little bit of coolant the spilled on it must have shorted it finally, but it's odd that it took three or four days of driving it before that happened... and it seriously wasn't a lot of coolant, maybe two ounces total with one ounce going into the alternator and one ounce on the pulley... which is why I originally thought the belt was just slipping on the slick pulley and causing it to drop to 12v more often then before (wouldn't jump back up to ~14v until I stopped the car and let it cool down and start again...)
Either way, might as well just replace it, I've freaking replaced everything else. I've got a new battery, I want it charged well, I want the car running well (boy it feels better then ever for the short time it WAS running!) and I seriously will now have VERY few things to worry about on that engine for another 50 to 100k!
I have noticed the last two winters random times that it would dip down to 12v while at a stop light and then as soon as I got on the gas it would jump back to like 13.5 to 14v so maybe it was on it's last legs...
Only thing I can think is the little bit of coolant the spilled on it must have shorted it finally, but it's odd that it took three or four days of driving it before that happened... and it seriously wasn't a lot of coolant, maybe two ounces total with one ounce going into the alternator and one ounce on the pulley... which is why I originally thought the belt was just slipping on the slick pulley and causing it to drop to 12v more often then before (wouldn't jump back up to ~14v until I stopped the car and let it cool down and start again...)
Either way, might as well just replace it, I've freaking replaced everything else. I've got a new battery, I want it charged well, I want the car running well (boy it feels better then ever for the short time it WAS running!) and I seriously will now have VERY few things to worry about on that engine for another 50 to 100k!
9/10 times it's just worn brushes on the VR. I've been able to replace some brushes on Bosch alternators (even used brush kits from the BMW-hisss! dealer) but the ones on the 150amp 4.2 alts are spot welded so I just replace the entire VR at 140K miles on General Principles. However, once the brushes are worn beyond the device limit and then some they will arc and probably damage the slip rings so the armature would have to be replaced and at that point it's rebuilt time. You can do it fast, cheap, or well. Pick two.
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Joined: Apr 2001
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From: Northern NJ
And don't forget to disconnect the battery prior to removing the leads. Some people claim you can remove the alternator without putting the car in service position but I don't see how (maybe if you had a lift and could easily access everything from below but even then.....). MUCH easier to put it in service position as 4D4 says.
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Ya. I don't mind service position too much since this will be the 3rd time I've done it in two months... It's especially easier this time since the timing belt isn't coming off and no crank lock pin!!
This is the Bosch one I was going to get, anyone that's replaced one (either a Bosch or Valeo unit) remember what part number the replacement Bosch was?
http://www.boschautoparts.com/m/Page...rt_num=AL0727X
It's a good price, claims to be exact fit if my car shipped with a Bosch unit to start with and I can get it from Amazon with Prime shipping...
However, there's a second unit on Bosch's web site which says it's a Bosch replacement for cars that shipped with Valeo units and it's a different part number...
The back of the unit does look a little different and this one claims to be 150 amp... Though I'm not sure if maybe that is a typo...
http://www.boschautoparts.com/m/Page...rt_num=AL0803X
Almost thinking of just ordering both from Amazon and trying to return the one I don't use, I THINK I'll be able to return it no questions asked, but last thing I need is being stuck with an extra alternator, lol
This is the Bosch one I was going to get, anyone that's replaced one (either a Bosch or Valeo unit) remember what part number the replacement Bosch was?
http://www.boschautoparts.com/m/Page...rt_num=AL0727X
It's a good price, claims to be exact fit if my car shipped with a Bosch unit to start with and I can get it from Amazon with Prime shipping...
However, there's a second unit on Bosch's web site which says it's a Bosch replacement for cars that shipped with Valeo units and it's a different part number...
The back of the unit does look a little different and this one claims to be 150 amp... Though I'm not sure if maybe that is a typo...
http://www.boschautoparts.com/m/Page...rt_num=AL0803X
Almost thinking of just ordering both from Amazon and trying to return the one I don't use, I THINK I'll be able to return it no questions asked, but last thing I need is being stuck with an extra alternator, lol
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Nothing is ever easy... Started doing the job today nice and slow while listening to a couple podcasts. Got her in service position, got under the car & removed rubber pipe that goes to pass side intercooler, then the metal pipe/bracket that the rubber one connected to. Have decent access to the alternator and removed the front long hex bolt and the other shorter bolt. Now it'll rotate a bit but I can't drop it out the car or pull it forward. Apparently I need to remove the huge counter hold bolt on the back. I don't have a spanner larger enough (20mm) for it and there isn't enough clearance back there to get a hex key or socket in it, or a 20mm socket over it... So the game is over tonight and tomorrow I go shopping for the right tool again.
Also having an impossible time getting the plastic connector with the little wires off... any tips? I figure once I can start to drop out the alternator there will be enough slack on the wire to rotate it a little bit and get a better angle to remove the connector. The larger wire that's bolted down to the back also seems crazy hard to remove unless the alternator is free to rotate a little, is that how you guys do it or am I missing something?
(Btw, following the Bentley procedure and it suggests I should be able to remove both connectors before the 3 mounting bolts... Though it also says I need to remove a cool air duct for the alternator and I'm almost positive I don't have that on my car... Or I'm blind...)
Also having an impossible time getting the plastic connector with the little wires off... any tips? I figure once I can start to drop out the alternator there will be enough slack on the wire to rotate it a little bit and get a better angle to remove the connector. The larger wire that's bolted down to the back also seems crazy hard to remove unless the alternator is free to rotate a little, is that how you guys do it or am I missing something?
(Btw, following the Bentley procedure and it suggests I should be able to remove both connectors before the 3 mounting bolts... Though it also says I need to remove a cool air duct for the alternator and I'm almost positive I don't have that on my car... Or I'm blind...)
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Nothing is ever easy... Started doing the job today nice and slow while listening to a couple podcasts. Got her in service position, got under the car & removed rubber pipe that goes to pass side intercooler, then the metal pipe/bracket that the rubber one connected to. Have decent access to the alternator and removed the front long hex bolt and the other shorter bolt. Now it'll rotate a bit but I can't drop it out the car or pull it forward. Apparently I need to remove the huge counter hold bolt on the back. I don't have a spanner larger enough (20mm) for it and there isn't enough clearance back there to get a hex key or socket in it, or a 20mm socket over it... So the game is over tonight and tomorrow I go shopping for the right tool again.
Also having an impossible time getting the plastic connector with the little wires off... any tips? I figure once I can start to drop out the alternator there will be enough slack on the wire to rotate it a little bit and get a better angle to remove the connector. The larger wire that's bolted down to the back also seems crazy hard to remove unless the alternator is free to rotate a little, is that how you guys do it or am I missing something?
(Btw, following the Bentley procedure and it suggests I should be able to remove both connectors before the 3 mounting bolts... Though it also says I need to remove a cool air duct for the alternator and I'm almost positive I don't have that on my car... Or I'm blind...)
Also having an impossible time getting the plastic connector with the little wires off... any tips? I figure once I can start to drop out the alternator there will be enough slack on the wire to rotate it a little bit and get a better angle to remove the connector. The larger wire that's bolted down to the back also seems crazy hard to remove unless the alternator is free to rotate a little, is that how you guys do it or am I missing something?
(Btw, following the Bentley procedure and it suggests I should be able to remove both connectors before the 3 mounting bolts... Though it also says I need to remove a cool air duct for the alternator and I'm almost positive I don't have that on my car... Or I'm blind...)
If you look at the new alternator you'll see how the long bolt goes through to secure it.
The back of the alternator has to clear where the mounting point where the bolt goes through. You just gotta muscle it a bit, rotate, clear the mount, push it outwards from the back, then get from under the car and try to find the right way to angle it out from the top.
It's an absolute pain in the ***, where removal and reinstalling the alternator doesn't seem to get any easier no matter how many times you do it.
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Joined: Sep 2010
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Just to help you reference where the alternator would be mounted:
My attempt at an explanation:
(Didn't feel like opening photoshop)
So as you can see, the ears of the alternator need to be rotated/pulled down out of the way to clear the mount.