CDT XPower Alternator Regulator dead after a day!

shaunlee75 · 13th March 2018, 21:04

So since I recently bought my 2005 ZT CDT XPower, I’d had a charge fault pop up anytime the revs went above 3000rpm.
I lived with it.

After the cold weather, discovered a dead battery. Bought a new battery, the following day, after a 40mile round trip, it was dead.

During that journey the dashboard was like a Christmas tree. No Radio, lights, heating, warning lights ABS, airbag, brakes, low voltage.

Diagnosed that the alternator regulator was below par.
Ordered a 2 pin 120A regulator.

Fitted the alternator regulator, checked the alignment, all looked good. With the new battery being fully recharged and fitted, after a 30 mile journey the dashboard was like a Christmas tree again, No Radio, lights, heating, warning lights ABS, airbag, brakes, low voltage, then car cut out.

On checking the outer most bush of the regulator after a 30 mile journey was fully melted.

I have checked the alternator model and it is Valeo 25422797B 70/120A YLE000260. So this is the correct regulator.

I just wondered if anyone had heard of anything similar.

Thanks in advance

Shaun

Mike Noc · 14th March 2018, 06:08

Hi Shaun, can't say as I have read of anyone having this particular problem on the forum, so all I can offer is a free bump.

Bit of info here from Chris (Stickman) on his alternator woes:

https://the75andztclub.co.uk/forum/s...d.php?t=203716

shaunlee75 · 14th March 2018, 06:56

Quote:

Originally Posted by Mike Noc

Hi Shaun, can't say as I have read of anyone having this particular problem on the forum, so all I can offer is a free bump.

Bit of info here from Chris (Stickman) on his alternator woes:

https://the75andztclub.co.uk/forum/s...d.php?t=203716

Thanks Mike, I will try some of this tonight.

Things checked so far:

Alternator spins and copper rings are clean.
Battery at 13.51v when turned off. No current draw.
At idle, battery at 12.72v and drops 0.01v every 30 seconds
With power from alternator disconnected and battery + disconnected, connectivity between both ends tested ok.

Could it be something as simple as an alternator fault pushing above the limit of the regulator? Or a wiring fault to the ECU therefore not regulating the output causing the melting of the brush?

Bear in mind that this happened within 1 hour of being fitted.

Missus was not happy as she tried to recover me with my straight bar an burnt her clutch out, so I hired a car for 2 weeks for her to use to get to work, and drop me at the bus. New clutch and slave cylinder fitted. Now happier but still has to take me to the bus.

Any thoughts please.

COLVERT · 14th March 2018, 13:39

To get true battery voltage let the battery stand for a few hours.

The voltage you are getting in not a true reading.

On tick-over you should be seeing 14 plus volts at the battery terminals.

The voltage you have shows the alternator is NOT charging.

If the regulator is doing its job the output from the alternator is controlled. You will only see a rising voltage in the system if the regulator is starting to fail. It can go high enough to blow fuses and bulbs.

In the case of where the regulator armature is good and also the brush pack and regulator brushes are OK then you might have burnt out field coils in the alternator body itself.---

shaunlee75 · 14th March 2018, 14:31

Quote:

Originally Posted by COLVERT

To get true battery voltage let the battery stand for a few hours.

The voltage you are getting in not a true reading.

On tick-over you should be seeing 14 plus volts at the battery terminals.

The voltage you have shows the alternator is NOT charging.

If the regulator is doing its job the output from the alternator is controlled. You will only see a rising voltage in the system if the regulator is starting to fail. It can go high enough to blow fuses and bulbs.

In the case of where the regulator armature is good and also the brush pack and regulator brushes are OK then you might have burnt out field coils in the alternator body itself.---

Colvert,

That’s what I am saying. The alternator is not charging because the brushes have burnt out within a few hours. But what is causing the brushes to melt?

COLVERT · 14th March 2018, 18:50

Quote:

Originally Posted by shaunlee75

Colvert,

That’s what I am saying. The alternator is not charging because the brushes have burnt out within a few hours. But what is causing the brushes to melt?

The only thing that can happen to stop the maximum of 6 amps going through the slip ring brushes is the regulator being faulty.

The brushes and slip rings are light duty components. ( as above, 6 amps. max. )

The battery is capable of pouring a huge amount of current through those brushes if the regulator doesn't apply the brakes.

Meltdown will quickly happen as you have found out.

You need a new correctly functioning regulator.------Sorry.

shaunlee75 · 14th March 2018, 19:28

Quote:

Originally Posted by COLVERT

The only thing that can happen to stop the maximum of 6 amps going through the slip ring brushes is the regulator being faulty.

The brushes and slip rings are light duty components. ( as above, 6 amps. max. )

The battery is capable of pouring a huge amount of current through those brushes if the regulator doesn't apply the brakes.

Meltdown will quickly happen as you have found out.

You need a new correctly functioning regulator.------Sorry.

Thanks Jon, I get all of that and appreciate your help, what I don’t get is that the new regulator was fitted the day before and only 10 miles were driven before the dashboard started playing up and another 20 before the brushes were melted.

If I assume correctly, even though the battery was new and voltage tested if there was too much load request by the battery on the alternator then the regulator would try to supply, the alternator would give and the brushes melt?

My only concern is that I get another regulator and another battery and I get the same problem a day later, then back to square one. I know that potentially that would be really bad luck, but I assume that there is nothing else in the circuit to check of test before that?

WillyHeckaslike · 14th March 2018, 20:07

Oil contamination of the alternator is a known problem with the diesel variants given its position in relation to the filler neck. Hope it's not this as the alternator is often rendered kaput by the contamination with a replacement being the only viable fix.

shaunlee75 · 14th March 2018, 21:32

Quote:

Originally Posted by WillyHeckaslike

Oil contamination of the alternator is a known problem with the diesel variants given its position in relation to the filler neck. Hope it's not this as the alternator is often rendered kaput by the contamination with a replacement being the only viable fix.

Willy, I assume oil contamination may not be obvious as the coil will get hot and the oil will seep to the core, and the smell may be difficult to sense given the location.

If the regulator were taken off and an ampmeter were put in series between the power post on the alternator and the lead that runs to the battery I assume that I would be able to measure up to 6A DC current. Or is this not an option to test contamination?

rustymotor · 15th March 2018, 05:50

Hi, don't know if this helps but, when I bought my CDTI the alternator wasn't charging, on the M3 driving it back to the North, the dash lit up like a xmas tree flashing all over the place. I changed the alternator for a new one and then checked the ECU the pollen filter had been wet through half way up, left bonnet up for most of the day to dry everything, replaced it and all was well.

13th March 2018, 21:04	#1
shaunlee75 Newbie MG ZT Saloon Join Date: Dec 2017 Location: March, Cambridgeshire Posts: 13 Thanks: 5 Thanked 0 Times in 0 Posts	CDT XPower Alternator Regulator dead after a day! So since I recently bought my 2005 ZT CDT XPower, I’d had a charge fault pop up anytime the revs went above 3000rpm. I lived with it. After the cold weather, discovered a dead battery. Bought a new battery, the following day, after a 40mile round trip, it was dead. During that journey the dashboard was like a Christmas tree. No Radio, lights, heating, warning lights ABS, airbag, brakes, low voltage. Diagnosed that the alternator regulator was below par. Ordered a 2 pin 120A regulator. Fitted the alternator regulator, checked the alignment, all looked good. With the new battery being fully recharged and fitted, after a 30 mile journey the dashboard was like a Christmas tree again, No Radio, lights, heating, warning lights ABS, airbag, brakes, low voltage, then car cut out. On checking the outer most bush of the regulator after a 30 mile journey was fully melted. I have checked the alternator model and it is Valeo 25422797B 70/120A YLE000260. So this is the correct regulator. I just wondered if anyone had heard of anything similar. Thanks in advance Shaun

14th March 2018, 06:08	#2
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,550 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Hi Shaun, can't say as I have read of anyone having this particular problem on the forum, so all I can offer is a free bump. Bit of info here from Chris (Stickman) on his alternator woes: https://the75andztclub.co.uk/forum/s...d.php?t=203716

14th March 2018, 13:39	#4
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	To get true battery voltage let the battery stand for a few hours. The voltage you are getting in not a true reading. On tick-over you should be seeing 14 plus volts at the battery terminals. The voltage you have shows the alternator is NOT charging. If the regulator is doing its job the output from the alternator is controlled. You will only see a rising voltage in the system if the regulator is starting to fail. It can go high enough to blow fuses and bulbs. In the case of where the regulator armature is good and also the brush pack and regulator brushes are OK then you might have burnt out field coils in the alternator body itself.---

14th March 2018, 20:07	#8
WillyHeckaslike This is my second home Rovers 75 & 25 Join Date: Oct 2010 Location: Wearside Posts: 4,522 Thanks: 543 Thanked 709 Times in 511 Posts	Oil contamination of the alternator is a known problem with the diesel variants given its position in relation to the filler neck. Hope it's not this as the alternator is often rendered kaput by the contamination with a replacement being the only viable fix.

15th March 2018, 05:50	#10
rustymotor Posted a thing or two Rover 75 Tourer Join Date: May 2017 Location: Hull Posts: 1,848 Thanks: 216 Thanked 432 Times in 340 Posts	Hi, don't know if this helps but, when I bought my CDTI the alternator wasn't charging, on the M3 driving it back to the North, the dash lit up like a xmas tree flashing all over the place. I changed the alternator for a new one and then checked the ECU the pollen filter had been wet through half way up, left bonnet up for most of the day to dry everything, replaced it and all was well.