996 Alternator help please.

[monthefish]

Pretty sure I'm needing a new alternator, 996 2000MY 3.4.

Thing is, Euro car parts have one for fitment up to 1999, and one 2000 onwards which is a bit strange:

I'm assuming the differentiating factor is the engine, i.e. 3.4 (up to mid 2001) and 3.6 (2001 onwards), or is there some other factor that affects which alternator should be fitted???

Also, I'm planning to change the voltage regulator as well (might as well whilst the alternator is out) - is the part for a Carrera the same as the turbo, as mentioned in this thread?

Angelus said:

Alternator is out, voltage regulator swapped, just to build it back up.

FYI, Bosch have updated the part number for the voltage regulator, and I've been assured it is the same part. Part number is now

F 00M 144 136 - 395.

[LeighB]

I thought I needed a new alternator, had one fitted and no difference at all to charging voltage. So, replaced a 3 year old Bosch battery and again no difference.

Few weeks ago my starter motor gave up and replaced that. What a difference!!

Let's hope you cure yours first attempt and sorry for offering no help to your question

Edited by LeighB on Friday 11th March 21:47

[Cerberaherts]

monthefish said:

The regulator is in the back of the alternator, so if you fit a new alternator, it already comes with a new regulator. Think the difference in the euro alternators is pulley size.

[Mousem40]

Why are you so sure you need a new alternator? It's almost always the regulator only that needs to be replaced. Try that first (sub £20 part) and see if that works before you buy an alternator. Then only buy a refurbished one at a fraction of the cost of a new one

[monthefish]

LeighB said:

I thought I needed a new alternator, had one fitted and no difference at all to charging voltage. So, replaced a 3 year old Bosch battery and again no difference.

Few weeks ago my starter motor gave up and replaced that. What a difference!!

Let's hope you cure yours first attempt and sorry for offering no help to your question

Edited by LeighB on Friday 11th March 21:47

Don't apologise - it's a helpful post.

I thought the battery was done, so bought a new one but it's made no difference (both Bosch).

Mousem40 said:

Why are you so sure you need a new alternator? It's almost always the regulator only that needs to be replaced. Try that first (sub £20 part) and see if that works before you buy an alternator. Then only buy a refurbished one at a fraction of the cost of a new one

Good point/question.
I was aware of that, but I believe the alternator needs taken out to access the regulator, and so the alternator will be out anyway. If the regulator isn't the issue, then I've got another weeks wait without the car whilst the garage orders one in and finds me a slot for them to fit it.
The car has over 100k miles and is over 15 years old and is generally in very good condition, so I feel I might as well just replace the alternator to be sure.

Also, the garage (local, not a porsche specialist) thinks it's the alternator from the brief checks he did using he voltmeter (although both failures probably display the same symptoms?)

[griffter]

The alternator I got from euro (to be fair I think there are several options) was a cheap refurb with a no-name regulator. I returned it and rebuilt my original one with a Bosch regulator which is what I'd advise you do.

Also check the earth strap behind the rear o/s wheel arch (clean connections). That can cause chargi issues too but the regulator solved mine.

[Pip1968]

What symptoms are you experiencing to think that the battery/voltage regulator/alternator is kaput??? What voltage is showing on the dashboard when the engine is running?

I had fluctuating voltage showing on my 996 and it turned out to just need a new regulator ~ £40 new (Bosch) from ebay.

Pip

[monthefish]

Pip1968 said:

What symptoms are you experiencing to think that the battery/voltage regulator/alternator is kaput??? What voltage is showing on the dashboard when the engine is running?

I had fluctuating voltage showing on my 996 and it turned out to just need a new regulator ~ £40 new (Bosch) from ebay.

Pip

The usual array of simultaneous warning lights (ABS, Airbag etc), voltage around 10, even when car is started, slow windscreen wipers etc

It may be the regulator but I might as well do both.

[halfpenny43]

monthefish said:

Pip1968 said:

What symptoms are you experiencing to think that the battery/voltage regulator/alternator is kaput??? What voltage is showing on the dashboard when the engine is running?

I had fluctuating voltage showing on my 996 and it turned out to just need a new regulator ~ £40 new (Bosch) from ebay.

Pip

The usual array of simultaneous warning lights (ABS, Airbag etc), voltage around 10, even when car is started, slow windscreen wipers etc

It may be the regulator but I might as well do both.

Interesting thread this as my 2003 Turbo is also suffering from the same symptoms as well as not starting on the first turn of the key. I have had a new battery and new ignition cylinder - so will be watching this with interest !

[Johnny G Pipe]

From memory the difference is after 99 they upgraded to a clutched pulley wheel which is kinder to the belt on sudden engine speed changes..or something like that.

Tbh I dont think it matters which alternator you use. I have a used one from a 3.4 in my 6T and it is totally fine.

[griffter]

I thought the clutched pulley was for manual cars, direct pulley for tiptronic. There are also 120 and 150 amp versions. Whether these are dependent on spec or year I don't know. The safest thing is to rebuild your own, or take it to someone who knows what the differences are and whether they matter.

[Mousem40]

monthefish said:

Good point/question.
I was aware of that, but I believe the alternator needs taken out to access the regulator, and so the alternator will be out anyway. If the regulator isn't the issue, then I've got another weeks wait without the car whilst the garage orders one in and finds me a slot for them to fit it.
The car has over 100k miles and is over 15 years old and is generally in very good condition, so I feel I might as well just replace the alternator to be sure.

Also, the garage (local, not a porsche specialist) thinks it's the alternator from the brief checks he did using he voltmeter (although both failures probably display the same symptoms?)

Removing the alternator is a 30 minute job, there are YouTube videos showing you how to do it. It's relatively simple.
Changing over the regulator will take 10 minutes. So try doing it yourself. I really doubt there is any problem with your alternator, I strongly suggest you try this first.

[monthefish]

Mousem40 said:

monthefish said:

Good point/question.
I was aware of that, but I believe the alternator needs taken out to access the regulator, and so the alternator will be out anyway. If the regulator isn't the issue, then I've got another weeks wait without the car whilst the garage orders one in and finds me a slot for them to fit it.
The car has over 100k miles and is over 15 years old and is generally in very good condition, so I feel I might as well just replace the alternator to be sure.

Also, the garage (local, not a porsche specialist) thinks it's the alternator from the brief checks he did using he voltmeter (although both failures probably display the same symptoms?)

Removing the alternator is a 30 minute job, there are YouTube videos showing you how to do it. It's relatively simple.
Changing over the regulator will take 10 minutes. So try doing it yourself. I really doubt there is any problem with your alternator, I strongly suggest you try this first.

Thanks.
Ok, I'll try just the regulator - is this part common between a 1999 Carrera 4 and a turbo? (i.e. if I buy the part number mentioned in my OP, will it fit my car???)

ETA this site
seems to think so...

frazerpart site said:

This will fit the following Porsche models

986 Boxster (2.5L, 2.7L), Boxster S (3.2L) 1997-2004 - All Models
987 Boxster (2.7L 2.9L), Boxster S (3.2L & 3.4L) 2005-2008 - All Models

987 Cayman (2.9L), Cayman S (3.4L) 2006-2008 - All Models

996 Carrera 2/4 (3.4L & 3.6L) 1998-2005 - All Models
996 Carrera 4S (3.6L) 1998-2005 - All Models
996 Turbo, Turbo S, GT2, GT3) 1998-2005 - All Models

997 Carrera 2/4 (3.6L) 2005-2008 - All Models
997 Carrera 2S/4S (3.8L) 2005-2008 - All Models

Edited by monthefish on Tuesday 15th March 16:55

[monthefish]

...seems pricey though at £57.60.

Are they not supposed to be a sub £20 part??

[Mousem40]

Have a search through pelican parts or EBay it's much cheaper there.

[griffter]

monthefish said:

...seems pricey though at £57.60.

Are they not supposed to be a sub £20 part??

Only for a non branded replacement. I got a Bosch equivalent listed for a Skoda.

Edited by griffter on Wednesday 16th March 12:39

[griffter]

Some more info here (my regulator was listed for a Skoda not an Audi but I'm sure it's a shared part with many manufacturers IIRC):

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

The thread on Pelican Parts linked from the one above is the best one I found on alternator removal/replacement and parts interchangeability. There are some good PDF parts lists to help determine interchangeability (google a part number you know is right as a starting point) but BEWARE - just because it looks the same doesn't mean it'll work.

I reckon you'd be lucky to do it in 30 mins. I'd advise taking your time to reduce the risk of stiff/seized parts chewing and shearing. As you'll see from the thread above I also took the opportunity to clean and protect the +ve wiring in the engine bay too (and subsequently did the engine earth strap as well) - but it was the regulator that fixed my charging issue.

I have to say it was only afterwards I wondered why I'd gone to such lengths to get a replacement Bosch regulator given that the original Bosch ones seem so prone to failing. But somehow I couldn't persuade myself an unbranded one was better.

[poppopbangbang]

As said above regulator is the main thing. Mine is still mostly original (regulator, brushes and rear bearing) and has covered nearly 300K miles!

[monthefish]

Bit of an update:

I have now sourced myself a regulator using the thread on pelican parts. I clicked on the 'Wood auto' link and bought the part listed (Ref; http://www.woodauto.com/Component.aspx?Ref=VRG4647... )

A couple of things - the chap at woods says that this regulator will only work with a Bosch alternator - is there any way of telling by looking at at installed alternator whether it's a Bosch or not? (no part numbers visible when installed).

Was a Bosch alternator OE fir across 996 range?

Also, the part that has arrived has arrived in a 'Woods auto' box, with a label on it saying Bosch, but the part itself doesn't have Bosch embossed on it, so I'm assuming its isn't a genuine part (I'm not overly bothered, as long as it functions).

[zulash]

Mousem40 said:

Why are you so sure you need a new alternator? It's almost always the regulator only that needs to be replaced. Try that first (sub £20 part) and see if that works before you buy an alternator. Then only buy a refurbished one at a fraction of the cost of a new one

Is this the same with all the alternators.? My car's a 997. A good friend recently paid £875 for a new alternator and a couple of very minor jobs on a 997. and that was at an Inde!