Is the Alternator dead? :-( - PeachParts Mercedes-Benz Forum

tivoliman · #1 05-05-2007, 08:24 PM

Car: 300E 1990, mileage unknown - recent purchase

Here's what I know ...

Car runs fine once started.
Car requires a jump to get started.
Changed batteries from one car to the next, and problem seems to stay
Took car to Auto Parts store, for a load test. When the load was applied, the car stalled.

Does this suggest the Alternator is dead?

Should I just replace the voltage regulator?

Thanks for the help.

I did a search - didn't see a hit.

Thanks.

ozawa · #2 05-05-2007, 09:25 PM

how exactly did they do this "load test?" usually when you're doing a charging system inspection, you rev the engine to about 2000rpm or so and then apply a load to the charging system to see its max. amperage output. did the car die even though the revs were held up?

if you're having to jumpstart the car three culprits come to mind:

1. alternator isn't doing its job (does the battery light ever come on when you're driving?)
2. battery won't take/hold a charge
3. excessive parasitic draw on the battery with the car shut off

tivoliman · #3 05-05-2007, 10:34 PM

The Load test - we did NOT rev the engine to 2,000; just let it idle - and with test applied - engine stalled

The counter guy may not have known what he's doing.

I'm thinking the Parasite comment may be right

Last weekend - the car worked each day, but the battery was dead after several days.

I will comment - today - the car always required a jump - even after two 45 minute drive - with a jump in between.

Thanks again for the suggestions.