Re my other thread about the warning lights I changed what I now suspect to be a perfectly good battery but thats fine as I now have a nice Bosch S5, when we checked voltage using the snap on reset tool it was 13.6 with no asc on running @ 2500 rpm as soon as everything was switche3d on it fell to under 12.5v and slowly rose to 13.5 @ about 3500rpm, the warning lights have stayed off but come on twice, both times when the lights were switched on and the car was idling, is it feasable the alt is the cause of all the problems as I believe it should read 14.6v at anything over tickover? Just its an expensive 'oh it may be that' if its not a possability. One day your life will flash before your eyes......................................make sure yours is worth watching!

Your alternator is almost certainly at fault.
The rectifier diodes appear to be on their last legs hence the red charge light appearing every now and again.
It will fail rapidly usually when its at the most inconvenient time.
My voltage, with the engine running, reads 14V almost permanently whatever engine speed or load on it.
Measured using a voltmeter installed in the cab.
Time for a new alternator or taking it to a good auto electrician for the diodes to be changed.

Last edited by nicedayforit on 28th Dec 2012 11:38am. Edited 1 time in total

Thanks should of made myself a bit clearer, the only warning light i DONT have is the charge light, I just dont think its putting out quite enough voltage to keep all the ecu's happy, I still hope its worth a go at changing the alternator but tomorrow im going to check it with a multimeter eng off, idle and under load then clean all the -ve & +ve connections and measure again. One day your life will flash before your eyes......................................make sure yours is worth watching!

There is one thing worth considering, the engine earth strap connections.
Given the age of your car they could well be corroded resulting in a voltage drop in the charging circuit.
As well as taking them apart and cleaning them it is also worth fitting an additional earth connection to the engine by using a jump lead. Simply connect the jump lead to the engine earth stud and a bit of metal attached to the engine.
Just see if it has any effect on alternator output voltage.
I'm a great believer in fitting an additional engine earth strap between the battery -ve post, or in the case of a RR the earth stud, and the engine, preferably an alternator mounting bolt. Saves a lot of problems with cars starting and charging as they get older.
If your charge light isn't on which lights are?

HDC/DSC/ABS and EAS. As soon as the new batt went on no lights but as soon as I used it at night and put the lights on while doing a tight turn the warning lights all came back on, I know from the live data as soon as load is applied the voltage drops a lot but slowly comes back up, I dont think this is ideal. One day your life will flash before your eyes......................................make sure yours is worth watching!

From what you describe I think you are draining the battery whilst using the car due to the fact the alternator is giving out a minimal output insufficient to continually charge the battery.
I'd be looking at the alternator.

Thanks, I am going to test it today as well as the earths etc, might even go the whole hog and test the leads for resistance etc as well as putting a better earth on the engine. If it is the alternator I may as well have a go at rebuilding it the parts arent to expensive and its worth the gamble, if it goes tits up ECP have one in stock for £275. One day your life will flash before your eyes......................................make sure yours is worth watching!

NDF can diode packs not be replaced at all? FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

PS whats the standard fit alternator to a 06MY TD6? as i've answered my own question and found plenty of kits on the bay and the like  FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

Yes diode packs can be replaced but on RR alternators they are mounted internally so you need to dismantle the alternator.
If you are confident to do this I don't see a great problem.

Happy to do it just need to know the model number as mines probably not happy from its dunkings over the last month and a bit so will take it out and see how much lithium grease i can protect it with

I would be tempted to encase it in a plastic shield but think it gets quite hot sometimes... FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

If your charge warning light isn't coming on there's nothing wrong with the diodes.
Alternators are surprisingly robust and don't generally suffer greatly with clean water immersion.
They don't like muddy water however, it's the grit in the mud that kills them.

The last bit is the bit im sure its had once or twice if its been upto bonnet level then its got to have touched it

Its been on once or twice but im not sure if thats been warning its been low and struggling to put a charge back into the battery after running the fbh and doing short 5mile trips to work and back though its had some nice 20mile runs the last few days and seems better now only coming on this morning after a full timed cycle as i didnt use it yesterday Best to take the early warning signs i think as generally my luck in the past with a car is that leaving it that little bit longer has made it a right mare to replace said item or made things worse... FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

Johnny when I was at the auto electricians he said overhauling the alternator was pretty straight forward. You just needed to cut the sealant from the case and then reseal once complete. Is probably having the balls to do it. I had a copy prob similar to what ECP are selling and it lasted lessthan4 weeks. [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

Check out this link, there is a link to a guide done by a Disco 3 owner (same type of alternator) showing how to replace diode packs. Once for a dark winter evening in the workshop.

http://www.fullfatrr.com/forum/topic14608....ator+diode

File now uploaded to gallery:

http://www.fullfatrr.com/gallery/albums/us...rnator.pdf .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

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