Did I get a bad alternator?
For a few minutes, the voltage read 14.0 volts after I replaced my Alternator and checked it with a VOM.
I took the car for a spin. The red charge indicator came on and when I got home, the voltage was a dead 12.0 volts.
Is there anything else "glitching"? I checked the Wiring Diagram and everything seem straightforward enough.
What the &(((%!! is going on. I am starting to get superstitious abou this car. My 300D never needs work, but my 240D keeps on breaking down....I am getting ready to trash this car,,,I think its cursed sometimes..


Replaced alternator, Battery Voltage at 12.0 volts, Red Battery Light on (83 240D)

Given that indeed the alternator is OK, check the battery and all the grounds and all the connections. Doubt much if it is a battery, however...

__________________
Adrian
'80 Mercedes 300D ..sold..
two Diesel VW caddies, old ones ..sold..
'96 Saab 900S

check the pully belt tension. It may of loosened up.

If that is not it then it is probably a bad voltage regulator which is externally mounted.

Do you have a new one or are you using your old one.

If you are using your old one that might have been the problem in the first place

good luck


bob

I have become used to the integrated regulator, does a Mercedes 240 really still use an external unit ???
Doubt if it is a slipping belt, but one never knows for certain..

We may be dealing with one of those "rebuilt" alternators from Autozone or Pep Boys. I suspect that all the "rebuilder" does is disassemble, clean, replace the brushes, test for 3 seconds(voltage only), and repackage - They make it look good, not necessarily truly good. The man who runs the semi-sweatshop makes his $50 per hour and the kid receives maybe $8 or less per hour.
The consumer is shafted to a degree..

__________________
Adrian
'80 Mercedes 300D ..sold..
two Diesel VW caddies, old ones ..sold..
'96 Saab 900S

I'm assuming that the 240D uses the same setup that the 300D uses, but it's a semi-external regulator assembly. You can replace it with the alternator in the car, but it does go into the alternator somewhat, and the brush assembly is integral to the regulator.

It's also held in place with two bolts so it's real easy to remove.

Hope that helps some...good luck!

The problem was due to a bad glow plug relay. The alternator was probably never bad.. I haven't replaced the glow plug relay yet, because its a $100 and I just bought a Robinair vacuum pump, so I do a manual connect-disconnect everytime I start her cold....

Thanks for all your help. dont know how I could do it without you all!

The Final Resolution

Carrameow, I'm glad you found the source of your problems. I had the exact same situation and it was also my glow plug relay. It was staying on and drawing current.

I replaced the voltage regulator-nothing, had two different batteries to work with-nothing. I even bought a new alternator-nothing. I was still only getting around 11.5-12.5 on the battery. I started disconnecting electrical components to see if the current would improve. Finally, when I disconnected the glow plug relay it popped right back up to normal.

I decided to take it apart and adjust and file down the two levers with contacts inside. That solved my problem. I had done that with my other car as well. I just sort of made the whole thing up. But it seems to have fixed things for the last 8 months.

Now, if I can only figure out why this is happening to my 1980 450SEL as well! I have no charge coming from what seems to be a brand new alternator?

Those gas burners are weird.