TDI Alternator Problem

**Paul Williams** · 07-01-2008,10:09 PM

I have a 51 plate 90bhp TDI Golf (70k miles) that I think has an alternator problem.
A couple of times recently when driving at night I noticed the head lights were a bit dim for the first mile and then at full brightness after that. Yesterday I checked volts on battery at start up which were 12V and then after about a mile when lights had reached full brightness the volts were at 14V with engine still running. So alternator seems to work (after one mile), as car starts OK and I haven't noticed any other problems. So my question is, is my Alternator about to fail or is there something else that could be causing the problem.
Also I got a quote of £185 +VAT for an exchange 120A Bosch alternator from my local VW specialist, does that sound about the right price.

Thanks
Paul

**Crasher** · 08-01-2008,12:13 AM

Try starting the car and revving it to say 2K for a moment and see what the charge says. The price sounds a little cheap but OK, for a genuine unit (2 year guarantee) it would be a little more.

**Paul Williams** · 08-01-2008,02:53 PM

After a bit more investigation have discovered that alternator starts charging when engine revved to 2.5K and happens every time engine is started whether hot or cold.
Paul

**Crasher** · 08-01-2008,05:10 PM

Just done a 2002 V6 4 Motion like that today, it didn't start charging until 2200 rpm. A new alternator fixed it but on a 4M you have to take the whole front of the car off.

**Paul Williams** · 08-01-2008,05:49 PM

Having had a quick look at the position of my alternator it looks a bit buried in the engine bay, how many hours of labour am I likely to be charged by a VW specialist to change it as I presume various bits and pieces have to be removed to get access.

**Crasher** · 08-01-2008,09:04 PM

What engine code?

**Paul Williams** · 08-01-2008,09:25 PM

When you say engine code, do you mean the engine number?
If so I will check in the morning and post reply.
Thanks

**Crasher** · 08-01-2008,09:45 PM

Yes, that is what I mean but only the three letters.

**Paul Williams** · 09-01-2008,11:50 AM

Engine code is ALH.

At the risk of looking a bit stupid, I thought that the ignition light came on if the alternator isn't charging, is that true or is it only when the battery volts start dropping?