'01 2.7 alternator almost dead

stl_tv · 05-03-2012, 05:26 AM

Greetings. Requesting info regarding alternator removal. I have the manual and have read other procedures that have the unit removed from front or bottom. Is one way preferred over the other? How much dissassembly is required? I've seen bumper-off, front in service postion and entire front removed including headlights!? Just don't want to start down the wrong path so looking for advice from someone who has been there.

Once out does it make any sense to attempt a partial rebuild? I've found a Regulator/Brush Assembly for $39 from aspwholesale.com. An entire rebuilt unit is $250 on-line. Many thanks...

4Driver4 · 05-03-2012, 06:16 AM

Buy a good quality replacement unit from Joe at Axis Motorsports. Alternator comes out the front. Service position is required; it is not necessary to tear the whole front end apart, service position is enough.

stl_tv · 05-03-2012, 06:54 AM

Thanks 4Driver4. I went to the site you recommended. Didn't find any alternators though. Does one have to special order?

RMsALFA · 05-03-2012, 07:26 AM

FYI in case you don't know.

The '01 model year had several different PN alternators. Be sure you get the number off your old one before ordering a replacement. Don't assume - get the number.

4Driver4 · 05-03-2012, 08:57 AM

Quote:

Originally Posted by stl_tv

Thanks 4Driver4. I went to the site you recommended. Didn't find any alternators though. Does one have to special order?

Call him. he drop ships most things either next day or shortly thereafter depending on your location.

stl_tv · 05-07-2012, 08:23 AM

Since I'm into it this far, in the service position, can I fix my aux cooling fan issue too? It doesn't work anymore. Used to sound like a jet turbine engine when it came on before. I guess I'll have to poke around and inspect things when I get in there. Hopefully it's the fan only and not the controller. Anything obvious to look for/inspect related to this fan? It's not a problem not having it functional right now but it will soon be 90 in the shade. Thanks again.

SloopJohnB@mac.com · 05-07-2012, 09:28 AM

I would replace the v/r and brush assembly first. There are little black boxes (Sun makes one, I have it from 10-20 years ago) that can diagnose open/shorted diodes, unvoltage, etc. from the waveform. Unless your alternator is making noise (bearing) or you know otherwise from such a test (you can even take the alternator out and to an auto parts store and they often have alternator/starter test machines) chances are the brushes are just worn.

If the slip rings haven't been damaged due to arcing you can just replace the v/r and brush assembly. IMHO the brushes should be replaced every 140K miles on GP, but the brushes often can't be replaced alone on these alternators...you have to look at the v/r and see if they're soldered in...spot welded is a deal breaker unless you have the spot welding equipment. I have a mig welder but didn't even try to use an electrode to spot weld much less source the pigtailed brushes (Bosch had them for my last alternator brush replacement on a volvo 740T).

Theoretically I could remove the alternator on my 2K4.2A6 without service position but I found it much easier to collapse and hold the tensioner as well as remove the long mounting bolt with the service position. The alternator on the 4.2 is on the bottom right of the engine and drops right out once the serp belt is off. The 2.7 has a different mounting position.

stl_tv · 05-07-2012, 11:50 AM

Thanks SloopJohnB. I agree that it is probably just the brushes. I had a load test performed at Advance Auto Parts just after I installed a fresh battery. On the drive there I noticed the voltmeter was reading just under 12V. Sure enough it wasn't the battery. The test result was that the voltage was OK without an electrical load (13.06V) but low with a load (11.89). I still don't know if the alternator has any output at all yet. I'll pull it and have it tested off-the-car. I also found a local rebuild shop that will disassemble it, do an eval and reassemble it for $10. Parts extra. If the off-the-car test shows it has some output then I'll start with the brushes.

RMsALFA · 05-07-2012, 02:49 PM

Quote:

Originally Posted by stl_tv

Since I'm into it this far, in the service position, can I fix my aux cooling fan issue too? It doesn't work anymore. Used to sound like a jet turbine engine when it came on before. I guess I'll have to poke around and inspect things when I get in there. Hopefully it's the fan only and not the controller. Anything obvious to look for/inspect related to this fan? It's not a problem not having it functional right now but it will soon be 90 in the shade. Thanks again.

You've probably found the on-line resource pertaining to this but, in case you have not...

The USUAL cause of the air raid siren is the primary fan (on the engine side of the radiator assembly) jamming and burning up the controller. Because of the reduced cooling capacity, the secondary fan runs full speed whenever the A/C is enabled.

There is a piece of rubber trim that jams the blades of the primary fan. I had the exact symptoms listed in the write-up and the cure was exactly as written. Remove the jam and replace the controller. All was 100% good after that, as the high dollar component (controller) failed and protected the low dollar component (fan).

It's much easier to replace the controller in service position, and yes, the controller is expensive.

pocketchange · 05-09-2012, 05:42 PM

Have a automotive electrical rebuild shop do their thing.

$250 seems a little steep.

I did bearing, rec and brushes for less than $90 (all it needed was the front bearing and brushes).
Then I'm **** when it's spread in front of me on the bench and all that's needed is parts.

If it to spins, forego bearings and if the brushes are used up replace them as the rec/voltage controller (very) rarely go away.

New battery is a nice touch if the old one is 5 or so years old btw.

pc

05-03-2012, 06:16 AM	#2
4Driver4 Tech Guru Garage is empty, add now Join Date: Oct 2002 Posts: 32,385	Buy a good quality replacement unit from Joe at Axis Motorsports. Alternator comes out the front. Service position is required; it is not necessary to tear the whole front end apart, service position is enough. __________________ 4Driver4 Growing old is mandatory; growing up is optional. 2005 A6 Sedan Q 3.2 (wife's whip) 2000 A4 Avant Q 2.8 (daily driver) 1980 VW Scirocco (mid-life crisis car) 1983 Mazda RX-7 (revolutionary sports car) 2003 Mini Cooper S (just because) 1995 Mazda Miata, Superdupercharged(anti-Audi) 1999 Mazda Miata SSB (track beotch, no plate) 2003 GMC Yukon Denali XL (the anti-earth) 2004 Dodge Dakota (hey, at least it's stick and 4x4)

05-03-2012, 07:26 AM	#4
RMsALFA AudiWorld Member Garage is empty, add now Join Date: Mar 2001 Posts: 165	FYI in case you don't know. The '01 model year had several different PN alternators. Be sure you get the number off your old one before ordering a replacement. Don't assume - get the number. __________________ 2001 A6 2.7t 6-speed; ECU & BiPipe by APR

05-07-2012, 08:23 AM	#6
stl_tv Audiworld Junior Member Garage is empty, add now Join Date: Oct 2007 Posts: 16	...a follow-up question Since I'm into it this far, in the service position, can I fix my aux cooling fan issue too? It doesn't work anymore. Used to sound like a jet turbine engine when it came on before. I guess I'll have to poke around and inspect things when I get in there. Hopefully it's the fan only and not the controller. Anything obvious to look for/inspect related to this fan? It's not a problem not having it functional right now but it will soon be 90 in the shade. Thanks again.

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05-03-2012, 06:54 AM	#3
stl_tv Audiworld Junior Member Garage is empty, add now Join Date: Oct 2007 Posts: 16	Thanks 4Driver4. I went to the site you recommended. Didn't find any alternators though. Does one have to special order?

05-07-2012, 09:28 AM	#7
SloopJohnB@mac.com AudiWorld Super User 2002 Audi S6 Join Date: Oct 2002 Posts: 4,150	I would replace the v/r and brush assembly first. There are little black boxes (Sun makes one, I have it from 10-20 years ago) that can diagnose open/shorted diodes, unvoltage, etc. from the waveform. Unless your alternator is making noise (bearing) or you know otherwise from such a test (you can even take the alternator out and to an auto parts store and they often have alternator/starter test machines) chances are the brushes are just worn. If the slip rings haven't been damaged due to arcing you can just replace the v/r and brush assembly. IMHO the brushes should be replaced every 140K miles on GP, but the brushes often can't be replaced alone on these alternators...you have to look at the v/r and see if they're soldered in...spot welded is a deal breaker unless you have the spot welding equipment. I have a mig welder but didn't even try to use an electrode to spot weld much less source the pigtailed brushes (Bosch had them for my last alternator brush replacement on a volvo 740T). Theoretically I could remove the alternator on my 2K4.2A6 without service position but I found it much easier to collapse and hold the tensioner as well as remove the long mounting bolt with the service position. The alternator on the 4.2 is on the bottom right of the engine and drops right out once the serp belt is off. The 2.7 has a different mounting position.

05-07-2012, 11:50 AM	#8
stl_tv Audiworld Junior Member Garage is empty, add now Join Date: Oct 2007 Posts: 16	Thanks SloopJohnB. I agree that it is probably just the brushes. I had a load test performed at Advance Auto Parts just after I installed a fresh battery. On the drive there I noticed the voltmeter was reading just under 12V. Sure enough it wasn't the battery. The test result was that the voltage was OK without an electrical load (13.06V) but low with a load (11.89). I still don't know if the alternator has any output at all yet. I'll pull it and have it tested off-the-car. I also found a local rebuild shop that will disassemble it, do an eval and reassemble it for $10. Parts extra. If the off-the-car test shows it has some output then I'll start with the brushes.

05-09-2012, 05:42 PM	#10
pocketchange AudiWorld Member 1999 Audi A8 Join Date: Aug 2011 Location: Houston Posts: 179	Have a automotive electrical rebuild shop do their thing. $250 seems a little steep. I did bearing, rec and brushes for less than $90 (all it needed was the front bearing and brushes). Then I'm **** when it's spread in front of me on the bench and all that's needed is parts. If it to spins, forego bearings and if the brushes are used up replace them as the rec/voltage controller (very) rarely go away. New battery is a nice touch if the old one is 5 or so years old btw. pc