1977 Mercedes 240d Battery Problem - PeachParts Mercedes-Benz Forum

zaq121 · #1 08-31-2007, 10:03 PM

Hi,

I am new to the mercedes diesel cars although I have owned many other mercedes cars in the past. The problem I'm having with my car is the battery light started coming on when driving. The next day the car wouldn't start but I could jump start it. I tested the battery and charged it and the car worked fine for a few days. I noticed that the turn signals would would blink slow and then the car died again. I am thinking this is an alternator problem but I want to get a few opinions before I buy a new alternator. Thanks for the help.

Zack

300SDog · #2 08-31-2007, 10:55 PM

Jumpstart the car again and get freebie battery test at wally's world, this will tell you status of alternator output too. Then pull the regulator (2 phillips screws on alternator back) and inspect the teeth for excessive wear. Often $20 reg needs replacement instead of $150 alt. And if you decide on new battery too then grab the largest battery on the shelf, diesels require helluva lot more juice to kick over than gasoline benz you're used to.

zaq121 · #3 09-01-2007, 11:36 AM

Thanks for the advice. I took my car to an auto parts store and they tested the alternator. He said the alternator output is low. I mentioned to him about the regulator which he agreed could cause my problem. I bought one and put it on. I charged the battery up and the light still comes on. I'm going to take it back there and have them check it again to see if it got any better. If the alternator is bad then what do you recommend to do? (new after market or rebuild). Thanks.

pj67coll · #4 09-01-2007, 07:20 PM

Be sure to check the wiring that goes to the alternator as well. I had lot's of trouble with my 240D's alternator. I changed the regulator which help for a while but then found that the wires going to the alternator were frayed so badly that some of them were not even making contact. In the end though I also had to replace the alternator.

- Peter.