PANTSYR

Hi there - new owner of an old S here.
Its probably been asked before (a dozen times) but:

I suspect either my alternator or voltage regulator might be on the way out.
Engine off my NEW (2days old) battery shows 12.35~12.40 volts across the posts.
Engine at idle = no change.
Idling with fan on and lights on 11.9~12.05.

The generator warning light has been flickering at idle revs when the car is hot, although it goes out after starting, sometimes after a quick blip to 2k RPM...

The battery that WAS in her when I got her was way to small (the same type oddly we have in our VW Polo 1.4) - so I swapped out for a large heavy duty battery.

From browsing around on these boards today - I should be seeing 13+ Volts at the battery with lights & fan on yes?

Very glad I signed up here - so much to learn and so much to find out.
Any assistance with this most welcome...

And pardon my newbiness.

PANTSYR

Oh and at 2.5k RPM with Lights and everything on: 12.3 over the battery posts.
Which seems rather low... to me anyway.

Steve Weiner-Rennsport Systems

How many miles are on the engine & alternator?

PANTSYR

175000 On the whole body. The engine's been rebuilt. The gearbox has been rebuilt. Not sure how many on the alternator.

Steve Weiner-Rennsport Systems

If the alternator has never been touched, I'd guess that it needs new brushes and slip rings. A good shop will check the diodes, too.

You should also check the voltage regulator to see its input voltage.

PANTSYR

Thanks Steve - she's at the electricians now.