Alternator going intermittently? - PeachParts Mercedes-Benz Forum

cewyattjr · #1 02-25-2008, 09:42 PM

So driving my daughter to her gym class tonight I noticed my radio kept turning off and on. Loose connection? Nope, low voltage, I'm sure of it. Next thing I notice that that pressing the brake was making the dash lights dim. Not good. I had one stop to make and of course after that, it wouldn't start.

A friend happened to be near by and gave me a jump start.

Anyway, another 10 miles to home, and it actually did seem to be charging. I turned the car off and tried and it would start easily.

When I've had an alternator go in other cars, it isn't an intermittent kind of thing. It just goes bye-bye. So, maybe just a graceful exit my MB 300d, and I should take it to the shop ASAP for a replacement?

Thanks,

Chuck

#2 02-25-2008, 09:56 PM

You can have the alternator and battery checked at you local auto parts store before you replace anything. However, check the simple stuff first; loose battery connections and loose ground cables from both the battery and engine.

cewyattjr · #3 02-25-2008, 10:05 PM

Yeah, that's a good call. In the lot, while jump starting, I did check those things and they seem tight, but may be worth double-checking. These engines vibrate enough at idle to jiggle anything loose.

#4 02-25-2008, 10:09 PM

If it's not obvious, go to the local "autozone" type place and ask them to check the battery/alternator, it takes about 5 minutes and it's free.

SD Blue · #5 02-25-2008, 10:41 PM

Check for corrosion both on and between the voltage regulator and alternator housing. This, recently, was the cause for my charging problems. Also, it's a simple 15 min. fix.

sixto · #6 02-25-2008, 10:45 PM

My money's on this -

http://catalog.worldpac.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=28G13A2TU2B41CRSNY&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=F4010-30110&application=000272327

Sixto
87 300D

rrgrassi · #7 02-26-2008, 12:03 AM

I had to replace both battery and alt, even thoug a week prior, both tested good. I was going to replace the voltage regulator, as the brushes were just nubs, but the stator was grooved by 1/8 to 1/4 in. A check of the records did not show an alt replacement prior to this.

toomany MBZ · #8 02-26-2008, 05:40 AM

Quote:

Originally Posted by sixto

My money's on this -

http://catalog.worldpac.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=28G13A2TU2B41CRSNY&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=F4010-30110&application=000272327

Sixto
87 300D

I second.

cewyattjr · #9 02-26-2008, 06:19 AM

Thanks all!

Where does the voltage regulator "live." I have a Volt/Ohm meter -- is there a simple way to test the voltage reg?

vstech · #10 02-26-2008, 08:46 AM

you will find on the back of the alternator, two 10mm screws, maybe 8mm, not sure... anyway they will be on either side of a round black thingie. pull it out and inspect the brushes, they should be at least 10mm protruding, if not, it's bad.

cewyattjr · #11 02-26-2008, 07:57 PM

OK, so drove to work and back home and everything seems normal, no more electrical misbehavior. Lousy weather and short on time today so not a chance to check things out. What's funny about these cars is that they seem to like to "warn" of impending failure, so I suppose I'm in for a regulator replacement but for now the brush strands appear to have rattled into place for a bit!

BTW, love that signature image, I passed that around the office today.

-Chuck

Larry Delor · #12 02-26-2008, 11:08 PM

I wouldn't wait too long to get the replacement. At least, the engine will stay running (once you get a jumpstart), and get you to where you need to be.