W203 Water cooled alternator

Chris R

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W203 270 CDI
Good morning all. I have a W203 270 CDi which has a water cooled Delphi 190 amp alternator.

About a year ago I started to see the Alternator / Battery warning light. Checked connections, checked battery and measured voltage etc. Eventually I concluded it was the regulator, bought a new one and managed, with some contortion... to change it without removing the alternator.

All was well for several months, but then the problem re-occurred. The voltage when running is 14.83 measured with a voltmeter at the battery. I do not seem to have the voltage measurement on the dash panel, the car was one of the early W203 models and does not appear to have this menu.

Apart from the Alternator / Battery warning light there does not seem to be a problem. The voltage doesn't appear high enough to cause a problem to the battery and all the electrics perform correctly, except for the automatic headlight function, which causes the headlights to go off momentarily when the warning light comes on, easily avoided by switching them on manually.

Any ideas please? Should I change the regulator again, I would like to avoid the expense of a new alternator if possible. Or could it be something more complicated?

Many thanks in advance.
 

LostKiwi

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14.83 is too high and will cause gassing of the battery - not good.
I'd check for a high resistance connection to the regulator and if nothing found change the regulator again.
 
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Chris R

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Thanks for the advice. It's not so easy to find a good reconditioning service where I live so I will try again with the regulator. This time I will remove the alternator from the car, something I avoided before, because of the water cooling.

Anything I should be aware of concerning the water cooling aspect, I have never had anything to do with a water cooled alternator before.

Thanks
 

LostKiwi

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Just use the correct coolant to top up. For yours it's probably G48.
 
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Chris R

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Thanks for the help.

I have a regulator and new brushes on order. Will let you know how it goes.

I think repairing the alternator is the easy bit, not looking forward to extracting it from the engine!
 
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