I have an e320 bluetec 2008 with a valeo alternator I had to replace.

I have the strangest issue. My alternator failed and I put a rebuilt valeo in. I connected the battery. Started the car and it showed 14 volts as expected.
I left it over night and started it again. It was not charging. I thought at first it was the contacts or the alternator had failed and replaced it. It then did the same thing.
I have then discovered that if I take the terminal off of the battery. Wait 10 minutes and put the terminal back on it will charge.
I can usually stop and start the engine a couple of times and then it will stop charging after the 3rd or 4th attempt.

Any thoughts or help would be greatly appreciated.

Philp.

Try a Bosch alternator. Or you may get lucky by just replacing the regulator with a Bosch regulator.
Just my $.02
Mike T.

Why did you have to replace the alternator in the first place and what was mileage?
When new alternator stops charging, did you try to rev it it higher to see if that would kick it in?

The alternator regulator wore out. I got a new regulator but then realized that the contacts had worn through, could not find a source for the contacts so bought another of the same type that was on the car. Mileage was 160k.
Tried revving it etc no difference. The only thing that worked is when I removed the post from the battery.

Thanks Mike I could try that but seems strange that it will charge after I take teh post off of the battery.

From what I know alternators on those cars are "self-sufficient" meaning there is no other controller than the build-in.
Correct me if I am wrong.
Rebuild alternators in Usa have very s****ty opinions, so that might be just another confirmation.