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View Full Version : 300 tdi alternator problems???


tmore
July 16th, 2007, 10:22 PM
I seemed to be jinxed with alternators..
My battery light came on yesterday, when I disconnect the main lead from the alternator and connect a multimeter from the post to ground I get apprx 16 volts. Is my voltage regulator dead??? what am I damaging by running temporarily at this voltage?

Any suggestions for a higher output/heavier duty alternator?
I have a nearly new mean green ( with 3 differant front plates) from my 3.9 in my garage, I am thinking about milling down the lower mounting point and seeing if I can fit it to the 300tdi if no other easier alternatives are available

The good news is I had just returned from a 2500+ mile road trip through Colorado, Utah, Nevada, Arizona.. at least it waited until I was home..

Thanks

Follow-up Post:

I checked the voltage while the enginge was running across several fuses and it was at 12.4 volts, which seems normal.. I am not sure what I am missing?

Buckon37s
July 17th, 2007, 12:29 AM
If you are in fact running at 16v or higher, over time that can hurt a battery. For a new alternator, contact Pendy on this board. I bought a 140 amp one from him many moons ago and it has worked perfectly. Way better than the stock unit.

JackW
August 15th, 2007, 09:21 AM
Buck - what brand/model of alternator is Pendy supplying? I was wondering about modifying one of the big Delco units to fit my 300tdi - I think the second Marelli 100 amp alternator is on the way out in my truck (in 80k miles!)

JFD
June 4th, 2008, 08:40 AM
Jack, did you change your alternator ? did you find
a drop in alternative brand model ?

Pat
June 4th, 2008, 09:08 AM
Measuring the voltage with the alternator main lead disconnected (open loop) is not right and you'll always get something like 16V or more. That does not mean your regulator is not working nor that tension is going to damage your battery either....
In the other hand, getting 12.4V with the alternator main lead connected (closed loop) is too low.. you should get something close to 14V when the alternator is charging...

battery shops can test the battery-alternator simulating an electric load, in a few minutes they can tell you where the real problem is.

Pat

cdb
June 4th, 2008, 05:25 PM
Eskra makes a copy of the Marelli Magneti that bolts right up for $350 to the 300 TDi. I have one and it has been fine. 110 amps I think.

Clark

JackW
June 4th, 2008, 06:28 PM
Jack, did you change your alternator ? did you find
a drop in alternative brand model ?
Turns out my alternator problem was a failing terminal connection at one of the wires. It also seems that it's only a wimpy 65 amp alternator.

I've been looking at a 100 amp (Bosch) alternator on ebay UK for around $155 but shipping to the USA is more than the price of the alternator! Still looking.....

junkyddog11
June 4th, 2008, 07:26 PM
Get a good used V8 alt..I think the disco version is like 120 Amp? generally cheap enough new and well cheap at the scrappy. Grind the back mounting ear of and bobs your uncle.

JFD
June 5th, 2008, 12:12 PM
Jack, how do you know the Bosch model from UK will fit ?
If you can get the model and/or ref number, may be you
can get it in the US...

Clark, where did you get this Eskra alternator, if I may ask ?

JackW
June 5th, 2008, 04:41 PM
Look at item # 120142706649 on Ebay - new 100 amp alternator for 300 Tdi

JFD
June 5th, 2008, 07:59 PM
Look at item # 120142706649 on Ebay - new 100 amp alternator for 300 Tdi

Yep, saw it on eBay. Not a lot of details about the product.
I have to check in the manual how many amps is the stock
unit, but I think it's around 80 or 90. I'd like to make an upgrade
that will bring me around 130/140. I use a/c all the time here.
What about adapting a Nippon Denso unit ? Is that realistic ?

cdb
June 5th, 2008, 09:35 PM
The company is Iskra,
the model is AAK 5326 and
their USA distributor can be reached at 800-474-1996

They even make a water cooled alternator but I don't think it would fit. Too bad, with that turbo so close to the alternator.

Clark

Buckon37s
June 5th, 2008, 10:14 PM
Yep, saw it on eBay. Not a lot of details about the product.
I have to check in the manual how many amps is the stock
unit, but I think it's around 80 or 90. I'd like to make an upgrade
that will bring me around 130/140. I use a/c all the time here.
What about adapting a Nippon Denso unit ? Is that realistic ?

Like I mentioned earlier, PM pendy on this board. He has a 140 amp bolt in alternator for the 300. I have it, it works perfectly. I believe he has units up to 190 or something like that.

JFD
June 6th, 2008, 05:50 PM
I believe there is several options and I think that is the idea of this post.
What other brand (Delco, Bosch, Denso, Valeo...) we can use as a
substitute for the Marelli unit, wich seems to be a little delicate.
A lot of board members are not in the US and have to try to find
local solutions. In my case, if I import a 300$ unit from the US,
I will have to pay another extra 200$ for shipping and customs :nono ...