gregc · Jun 28, 2014

Last week I borrowed the father in laws Discovery 300tdi. It struggled to start but got going, I left it running for half an hour then turned it off. When I came to restart it wouldn't turn over, I popped the bonnet and noticed that the serpentine belt was in tatters and the waterpump and given up. Anyway I jump started and drove home (about a mile). I've reached the belt and pump today but I've now noticed that there is no battery light (not even before starting) and no rev counter. Could the belt failing have damaged the alternator?
All the wiring looks good, I've got continuity from the alternator to the battery.
Has anyone seen this before? Or have a clue what to do next?

jamesmartin · Jun 28, 2014

is the feed wire from warning light secured to d+ terminal and has 12v when ignitions switched on , if so it would sound like you need another alt

gregc · Jun 28, 2014

I've taken the battery off to charge at the moment. Will check the d+ for 12v when I refit it.

Datatek · Jun 28, 2014

gregc said:
Last week I borrowed the father in laws Discovery 300tdi. It struggled to start but got going, I left it running for half an hour then turned it off. When I came to restart it wouldn't turn over, I popped the bonnet and noticed that the serpentine belt was in tatters and the waterpump and given up. Anyway I jump started and drove home (about a mile). I've reached the belt and pump today but I've now noticed that there is no battery light (not even before starting) and no rev counter. Could the belt failing have damaged the alternator?
All the wiring looks good, I've got continuity from the alternator to the battery.
Has anyone seen this before? Or have a clue what to do next?

Rev counter is usually driven from the alternator on diesels, so if it's not turning due to a failed belt rev counter will not work. No battery light could be the bulb, wiring or alternator.
You can just grounfd the D+ wire and see if the light comes on to test it.

gregc · Jun 28, 2014

The alternator turns freely I was just thinking that maybe when the old belt was breaking down a bit could have got inside the alternator and damaged the internals?

gregc · Jun 30, 2014

I grounded out the wire and the light came on and I'm getting no output when it's running. Looks like he needs a new alternator.
Thanks for you help jamesmartin and Datatek.

Datatek · Jun 30, 2014

gregc said:
I grounded out the wire and the light came on and I'm getting no output when it's running. Looks like he needs a new alternator.
Thanks for you help jamesmartin and Datatek.

New regulator, brushes and diode pack would be cheaper than a new alternator

gregc · Jun 30, 2014

Datatek said:
New regulator, brushes and diode pack would be cheaper than a new alternator

Tell me more! How long will it take? Any special tools required?

Datatek · Jun 30, 2014

gregc said:
Tell me more! How long will it take? Any special tools required?

Unless the slip rings need skimming, I can do it in half an hour. You may need to be able to solder. No other special tools although it's a good idea to give the insides a good clean to get rid of all the dust and ****e and also a DVM to check the windings are not open circuit, pretty rare. It's also possible to fit new bearings.

gregc · Jun 30, 2014

I'll look at doing that. I've got a second hand one from eBay coming so will rebuild this one as a spare.
Cheers

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