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[mc9]

Fully charged battery voltage 12.7V, engine off.

Engine running 2000rpm, battery voltage still 12.7V.

Looks like alternator has failed but no dash battery or charge warning lights are showing. Any other known cause of failure to charge battery?

Is alternator replacement difficult or expensive?

Cheers, mc9

[TheBoy]

On a TD, check the aux belt isn't badly slipping (sometimes, if idler has failed, you don't get a squeal). Note, if belt slips badly, car will overheat.

Beyond that, looks like alternator

[zirk]

As said, sounds like a charging issue, only other thing that can happen on the TD is the Glow Plug Relay sometimes gets stuck on, causing all the charge current to be drained, quick check when its running pull the top connection off the GP Relay and see if the Charge Voltage jumps up to normal.

[mc9]

Which is GP relay? Pulled relay 40 (upper left corner) and the engine stopped.

Using Occam's razer, assume alternator is bugggered (I know the battery is good). I can see it, but I don't want to change it myself -- suppose a competant independant garage could do it easily.

Is this a service exchange part -- any recommendations for a good exchange?

Thanks, mc9

[zirk]

Which is GP relay? Pulled relay 40 (upper left corner) and the engine stopped.

Using Occam's razer, assume alternator is bugggered (I know the battery is good). I can see it, but I don't want to change it myself -- suppose a competant independant garage could do it easily.

Is this a service exchange part -- any recommendations for a good exchange?

Thanks, mc9

Fuse Box next to Battery, Black Relay (BMW logo on it) nearest the back engine side, theres a red lead connected to the side of it, Multi way connector on top pulls off from memory.

Worth a check, but like you think your alternator is furbed. Not sure if the Petrol Migs use the same type, but might be worth asking in Parts Wanted Section. 

[TheBoy]

Grrr, I had a spare friggin TD alternator left over from Project Tractor.  Grrr  .  In the bloody garage 


TD alternator change is fiddly, as although its easy to undo and disconnect, its a pig to remove. Either risk damaging rad, or bend battery tray. No other options.

[relluf]

I had mine fail a few months ago ,managed to get it off but as TB says it is a real job to get out of the space available, you pretty much have to get brutal with the battery tray to make room to extract it.
Mine was refurbed by a local guy for about £40.00 and comes back like new with a warranty!
It also goes back in a lot easier then just try and get battery tray back into shape again.
Good luck.
There is a how to somewhere just cant find it at the moment.