www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You




Go Back   TDIClub Forums > TDI Model Specific Discussions Areas > VW B5 Passat TDIs

VW B5 Passat TDIs This is a general discussion about B5 Passat(>98 (2004-2005 in North America)). Non TDI related postings will be moved or removed.

Reply
 
Thread Tools
Old October 1st, 2011, 21:08   #1
db52282
Member
 
Join Date: Aug 2010
Location: Georgia
Fuel Economy: 38 - 41 MPG
Default Alternator Workshop - Bad Alternator or VR?

Wife's 2005 Passat TDI (BHW) got the battery light and the Alternator Workshop notification (with the beeping).

Alternator pulley was replaced (new style) around 30K miles ago.

I have not determined whether I have the Valeo or Bosch alternator yet
but am leaning toward replacing the voltage regulator rather than the
entire alternator. The rebuilt units are VERY expensive.

Has anyone had the same problem and a voltage regulator replacement fixed the problem?

I read in the TDI 101 section that you should only replace the alternator if you have a bad bearing.

Any ideas or help is appreciated.
__________________
2005 Passat TDI (Unchained 05/03/2011 @ 87273 Miles)
2007 Chevrolet 2500HD Duramax LBZ Diesel
db52282 is offline   Reply With Quote
Old October 1st, 2011, 22:14   #2
afarfalla
Veteran Member
 
afarfalla's Avatar
 
Join Date: Nov 2006
Location: sugar land tx
Default

get a voltmeter, set it to voltage, put the red lead to the bat positive, blk to the neg, read bat voltage, start the car, if the bat is weak the voltage should go up higher than the first reading, in any case the voltage should be around 13 to 14 volts, now turn on the lights radio anything that draws power, if the regulator is good the voltage should hold
afarfalla is offline   Reply With Quote
Old October 2nd, 2011, 05:51   #3
thundershorts
Veteran Member
Default

battery condition/age? Most auto stores will test your battery and charging system for no charge(pun intended)
__________________
"You can't argue with a fool..."
thundershorts is offline   Reply With Quote
Old October 2nd, 2011, 06:18   #4
db52282
Member
 
Join Date: Aug 2010
Location: Georgia
Fuel Economy: 38 - 41 MPG
Default

I had the battery and alternator checked at the parts store. Battery age unknown.

Results: Battery tested good - 12.4v

Alternator: Failed - Producing 12.1v (Load or No-Load Condition)

Any additional advice?
__________________
2005 Passat TDI (Unchained 05/03/2011 @ 87273 Miles)
2007 Chevrolet 2500HD Duramax LBZ Diesel
db52282 is offline   Reply With Quote
Old October 2nd, 2011, 07:44   #5
Skivvies
Member
 
Join Date: Jun 2006
Location: Westford, MA
Default

I had a similar problem, and when testing at the battery as suggested with car running I got less than 13vdc. The voltage would intermittently spike and the engine rpm would fluctuate in accordance with this spike (indicating the alternator was coming into and out of the loop), but for most of the time the voltage was below 13vdc. Pulley had already been replaced with new style but I checked the clutch mechanism anyway.
I replaced the voltage regulator and alternator output returned to normal. I would replace the regulator with one from the dealer (P/N 038903803EX). The cost was the same as online and it got to me in a day or two with no shipping charge. You can do it without removing the alternator.
I will add that at this time the battery looked like the original and a few months later it needed to be replaced. Whether it contributed to the failure of voltage regulator I don't know.
Skivvies is offline   Reply With Quote
Old October 2nd, 2011, 13:09   #6
db52282
Member
 
Join Date: Aug 2010
Location: Georgia
Fuel Economy: 38 - 41 MPG
Default

Quote:
Originally Posted by Skivvies View Post
I would replace the regulator with one from the dealer (P/N 038903803EX).
Do you have a Valeo or Bosch alternator?

Is this part number the same for either the Valeo or Bosch?

Thanks for the information. I was heavily leaning toward replacing
the VR anyway.
__________________
2005 Passat TDI (Unchained 05/03/2011 @ 87273 Miles)
2007 Chevrolet 2500HD Duramax LBZ Diesel
db52282 is offline   Reply With Quote
Old October 2nd, 2011, 17:46   #7
thundershorts
Veteran Member
Default

did they give you a printout of the system test? if the battery is original Varta I would consider replacing it with the vr or alternator. it might still test good in warm weather but may give troble when it gets cold
__________________
"You can't argue with a fool..."
thundershorts is offline   Reply With Quote
Old October 2nd, 2011, 18:28   #8
Skivvies
Member
 
Join Date: Jun 2006
Location: Westford, MA
Default

Quote:
Originally Posted by db52282 View Post
Do you have a Valeo or Bosch alternator?

Is this part number the same for either the Valeo or Bosch?

Thanks for the information. I was heavily leaning toward replacing
the VR anyway.

alternator is a Bosch 120A P/N 028903031. This is printed on the backside of the alternator. You can give whatever alternator P/N you have to the dealer to find regulator P/N. The following site has all the info you need including the Valeo and Bosch regulator P/Ns:
http://www.myturbodiesel.com/1000q/b...at-removal.htm
Skivvies is offline   Reply With Quote
Old October 23rd, 2012, 01:29   #9
Za786
Newbie
 
Join Date: Oct 2012
Location: Leicester
TDI(s): Passat tdi
Default 04 Passat Tdi alternator workshop

Hi guys,

My alternator light came on the problem was the pulley was gone as when I turned the steering it would squeak.. After I got the pulley changed it was fine.
Now after a month i went to work every morning 30 mile journey each way and no problems but as soon as I returned home in the evening and switched the car off and on immediately the light came on.
Now from yday the light came on immediately and no problems on battery draining yet. The alternator is showing more than 13v
Does anyone know if it's the regulator? Where does that sit and how much is it?
Any help will be appreciated
Za786 is offline   Reply With Quote
Old October 24th, 2012, 08:46   #10
abctdi
Veteran Member
 
abctdi's Avatar
 
Join Date: Mar 2004
Location: ABQ, NM, USA
Default

Maybe new brushes will help?
When my pulley failed, I measured mine since they were easy to get to and they were still long enough.
__________________
05 Passat GLS 2.0 PD, UnChained & Steel GPs by VW, 15" steelies, New TB/WP, motor mounts, alt pulley, trans filter, cv boots, TSB #P9/66C8, clear bra & tint, both raxles. Now only driven 1-2 times per week. 123k miles (sold)

DD is a 2012 Kia Optima SX turbo with 274 hp and 269lb-ft@1,750-4,500rpm
abctdi is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
alternator workshop krober VW B5 Passat TDIs 2 February 18th, 2010 15:50
Alternator Pulley bad, now Alternator? danielalves VW MKIV-A4 TDIs (VE and PD) 6 July 28th, 2009 05:32
Alternator Workshop b5r VW B5 Passat TDIs 2 March 22nd, 2009 11:36
alternator workshop? diesel#2 VW B5 Passat TDIs 6 June 12th, 2008 20:26
Alternator Workshop! What does it mean? Occams_Razor VW MKIV-A4 TDIs (VE and PD) 5 December 20th, 2003 14:40


All times are GMT -7. The time now is 10:28.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
1996 - 2017, All Rights Reserved
Page generated in 0.19084 seconds with 11 queries
[Output: 96.26 Kb. compressed to 81.92 Kb. by saving 14.34 Kb. (14.90%)]