[RussHatton]

OK guys as Jack suggested have started a second thread, regarding the battery light. Car came back from machanic last night with new belt fitted, whilst this has improved the situtation the light is still coming on. My machanic ( he is a good guy ) thinks that there is nothing wrong with the alternator however he believes the problem may lie with the alternator clutch which he thinks is overrunning. His reason is the visable movement and vibration in the clutch at both high and low revs. Has anyone see this and any comments on the diagnostics. As he is going to change clutch may as well go for an alternator at the same time ?

 

[jackwalton]

OK guys as Jack suggested have started a second thread, regarding the battery light. Car came back from machanic last night with new belt fitted, whilst this has improved the situtation the light is still coming on. My machanic ( he is a good guy ) thinks that there is nothing wrong with the alternator however he believes the problem may lie with the alternator clutch which he thinks is overrunning. His reason is the visable movement and vibration in the clutch at both high and low revs. Has anyone see this and any comments on the diagnostics. As he is going to change clutch may as well go for an alternator at the same time ?

Sounds as though you may have got a good guy there doing your diagnosis.
Clutch pulleys can fail and result in charging problems and belt tensioners needing to do a lot of work. I suppose it comes down to cost and how much he would charge for just changing the pulley and whether its practical to change the pulley while the alternators still on the car.

Its a fairly big job to swap an alternator and it could be more cost effective to bite the bullet and swap the alternator for a new one as you suggest.

Or run with it as it is and see how it goes ?
At least your in a position where your aware of the problem and can keep your eye on battery voltage while running. The battery isn't suddenly going to fail on you, you will get plenty of warning if you keep an eye on the charging voltage and the voltage before cranking the engine on start up.

jack

 

[RussHatton]

OK so we decided to go straight with the new alterator. Taking the car back this afternoon 2 mile drive. Dashboard lights up like a Christmas Tree, more chimes than Big Ben. Heaters blow full belt and wiper work on there own. Stop, obvioulsy car would not turn over dead as a DoDo only 8 volts in EVIC, please please tell me this could be the alternator letting go big time stylie

 

[DESIREE]

How old is the battery?
What is the state of the battery's charge?
With an independent voltmeter, what is the battery voltage before starting the engine?

 

[RussHatton]

Not sure of age but in good condition was charging at 14.5 before it happened

 

[devilmaycare]

"Charging at 14.5" provides no information of battery condition, only that the alternator was working at the time you were monitoring the voltage. Before starting the engine, a fully charged battery on light load should have 12.6V. The voltage on cranking should not drop below 9V. The symptoms you describe certainly tie up with intermittent alternator operation resulting in poor battery charging. If the battery is old, then its ability to retain charge, even with a good alternator, will be seriously compromised. If you don't know the age of the battery it would be a good idea to change that alongside the alternator. CRD batteries (and they do get some hammering with all the electrics) seem to have an average life of about 5 or 6 years. I had to change both my battery and alternator at 7 years.

 

[jackwalton]

Sounds as though alternator could have packed in big time and drawing excessive current or battery has failed big time.

Connect a temporary low current scource 12v supply in place of battery NOT AS WELL AS CAR BATTERY, IN PLACE OF. ( A big 9v dry battery will do) without turning ignition on and check current drawn and to maintain 12v supply to ECM. With temporary supply connected measure current drawn or battery voltage, if voltage has collapsed because current is very high, disconnect dry battery then alternator which could be drawing excessive current, then reconnect dry battery and retry. Current should be as high as about 3Amps when initially connected but quickly drop over about 1 minute to less than 0.5 Amps.

Recharge car battery, check open circuit volts which i assume will be low. Recharge battery and swap alternator if its drawing excessive current.

Now that was a serious failure.

jack

 

[badgx]

The clutch type pulley should allow a firm slip when rotated in one direction only and lock in the other direction. Smooth operation, no vibration or noise.

Hopefully this video should explain it. Normally when you buy an new alternator, I would have thought the clutch comes attached with it.

Alternator clutch pulley diagnose and replacing,VW / AUDI /SEAT / SKODA - YouTube

 

[RussHatton]

Thanks guys, car being looked at today,hopefully new alternator and possibly new battery will sort the old girl, out.In the mean time driving up and down M4 in a Corsa hire car, boy how you miss something when you don't have it