Stranded for first time today..... - PeachParts Mercedes-Benz Forum

#1 11-13-2002, 02:59 PM

Mother was driving car for the day. She went to market, came back outside and car would no start. Battery problem. She got a jump from a fellow diesel person (Ford Truck) and off she went. Obviously not alternator because she came home parked it, and when I started it, it fired right up. Could battery need to be changed? Its the original one that was with car.....my brother in law has a new battery I lent him

What are some possible issues, and what would I need to check if my battery is going out the door?

#2 11-13-2002, 03:04 PM

Put a voltmeter across the battery with engine stopped. It should read about 12 volts. Start the engine and the voltmeter should read about 13.5 to 14.3 volts. If it stays at about 12 volts after the engine is started, there is a problem with the alternator or associated wiring. If it goes to the 13.5 to 14.3 volts on startup, the battery is suspect. Also, don't overlook the possibility that she might have just left the lights turned on or something like that.

Good luck,

Nate Stanley · #3 11-13-2002, 03:09 PM

Kyle,
It be the beginning of the end for your solenoid. Did the car "click" when she turned the key, or did it just not do anything at all?

When my soleniod gave out, I got the click, but no starter engagement. It usuaally happened when the engine was hot, cold starts were fine.

The condition gradually worsened until even hotwiring it from the junction block on the passenger side fender well didn't work.

There's plenty of postings on starter replacement on this site, but if you don't want to do the R & R yourself, NO decent tech should charge you more that 1 hr labor to replace, and also- spend the $ and get a genuine Bosch rebuld.

#4 11-13-2002, 03:19 PM

Just checked......weird....I checked it stopped...it reads twelve...and after startup it continues to read twelve. Yet, even after I let it set for the time my mother did, it continues to start without a problem...Should it be reading 12 volts all around?

BTW Nate, mother had many other cars with broken starters....she says shes positive it was not the starter...Weird...maybe just a freak thing....alternator is working because lights are powered and i does not lsoe energy to start more than suggested time. While driving car about 15 miles, it continued to start after trip, lights functioned fine...maybe a freak thing?

RG5384 · #5 11-13-2002, 03:34 PM

keep in mind that the diesel engine requires no batter to run, so it is very possible that a fully charged batter could last a little while. When my alternator was going south i would charge it over night, and i'd be able to run my a/c, my stereo(with amp) and lights many times and as long as i plugged it in at night it would work just fine. My alternator was completely shot, and normally by the time i brought the car home my electrics were starting to die, but this should give you some idea of how one of the better batteries in these diesels can hold up
R

#6 11-13-2002, 05:28 PM

What else could it be? If it is 12 volts after startup the alternator is suspect? The pully is still turning the alternator. I hope these dont cost much...

ck42 · #7 11-13-2002, 06:18 PM

Jep...12V with the engine running very much points to the alternator....of course, there's always the oddball possibility that something else is causing it....you know, the 1 in a 1000 chance...but don't count on it.

Also, a hot motor would need the battery less for glowing vs a cold motor.....if this has any relevance to the behavior you're seeing.

No idea on pricing....give Fastlane a lookup. Haven't replaced one on a MB before (yet) but it looks pretty standard.

RG5384 · #8 11-13-2002, 07:12 PM

when i replaced mine i think it was around 250. I didn't have time to repair it myself, so it was towed to a shop, and the two belts had to be replaced as well as the alternator locked up. I think the total repair bill including towing was around 375 or so.
Ryan

P.E.Haiges · #9 11-13-2002, 11:47 PM

Kyle,

If the voltage is only 12 volts when engine is runnung, the alternator is not working. It has to generate 13 to 14 volts to charge the battery.

First check the brushes in the alternator. They are easily removed by taking out 2 small screws in the ALT. NOTE: ALT does not have to be removed. If the brushes are worn down to about 1/2 cm or less, they need to be replaced. They only cost a few dollars.

Funny thing about a MB, if the brushes do not work, ALT light will not illuminate. Something about the ALT light circuit going thru the brushes.

P E H

BobK · #10 11-14-2002, 07:30 AM

One other goofy thing to check: Read the voltage at the lead posts, then again at the connectors on the battery cables. My experience has been that you will get an insulating corrision between the post and the connectors when the days have large temperature swings like we have now with the seasons changing. Daughter's 123 had that problem about two weeks ago. Battery was not charging because of bad connection. Cleaned posts and connectors and all is fine now. If you still read low voltage at battery, read voltage directly at alternator. I have seent he connections on the fenderwell get so bad that nothing was making it from the alt. to the battery. Drove me crazy until I started at the alt. and just walked the meter back towards the battery and saw the voltage suddenly drop . Just had to unscrew the connections and clean them up with wire brush.

CSchmidt · #11 11-16-2002, 11:40 PM

Folks,

One other area that can cause intermittent "dead battery" symptoms is a battery short. I've had them start fine, then all of a sudden so dead they hardly work the horn. Get a jump, shake'em around a little and they are fine -for a little while. If this happens the battery needs replacement. May not be the solution for this one.

I agree the charging voltage should be 13.5V+ (with no accessories running at idle).

Chuck