Hello to everyone,

I am new to this forum and am asking for help with my 1987 300D Turbo (DIESEL)sedan. This past couple of weeks I have been having a hard time starting the car. The battery was replaced last year and the car has 200,000miles on it and was bought by my father new. The past couple of weeks I leave the car alone and not started for a couple of days and the battery is dead and I have to jump it. It started to get worse to the point I have to jump it if the car is not driven for a day. I believe the car is not getting a car.....alternator?starte?battery? I really dont know and I am getting frustrated. Lateley I have to jump the car if I dont run it for even 8 hours. Now everytime I want to drive I have to jump start the car. When I turn the key no lights show and if they show, the intrument lights are dim and the sound that lets you know that there is a key in the ignition is weak like its almost dead. I brought the car to Kragen and asked for a quick battery check and they had their little tester that was connected to the battery and said it cranked at 13volts which I believe is the correct voltage. The device they had check the alternator and starter and that checked out fine. I work all day so dont have the time to bring it to an independent mercedes shop. When I get it going and start driving, the car seems fine. Its only when I turn off the car and try to start it again. Now when even driving for an hour and then I turn off the car and try to start it back up again it is dead...PLEASE HELP with some advice. I want to fix it myself if I can. Please email me at manongb@hotmail.com if you can help me. Thank you all and hope this can be resolved so I can enjoy my car and this site.

Brian
manongb@hotmail.com

 

How many miles do you normally drive the car? Is it far enough to charge the battery?

The battery cables may be loose and/or dirty. Here's what I would do ...

Unhook the battery and clean the battery posts and cable connectors. Use a battery post and connector cleaner with steel brushes. Clean them even if you're sure they're already clean.

Reconnect the cables and make sure they are very tight. Wiggle the connectors while you tighten but be careful not to damage the battery posts. If they're even a little bit loose the battery's charge may not make it to the cables.

Give the battery a good charge, either with a charger or a long drive.

 

thanks for the response. I did all that and I commute with the car 50miles each way to and from work. I tried again starting the car as soon as I got to work this morning and still DEAD....nothing....wouldnt start back up.... it tried but no luck.....thanks though for the quick response

 

Go to your local auto parts store and buy a battery tester, around $10.00. First test the battery with the engine off and key out. If the tester shows anything below 12.5 volts you got a problem, next check the battery with the car running, if the volts are below 13.5, then turn on your lights radio, AC if equipped and any else that runs off the batter, if it drops down to 13 or lower volts,you need a new alternator, and battery,from what you are describing a slow charge ain't gonna fix it. Is there any white powder on the battery or the battery pan? If so the battery is leaking, also if you buy an alternator, buy a new drive belt.

 

New to this forum, but have you check the size of your battery[sm=smiley20.gif]? I think that will also make a difference.

 

Good Point, could be the wrong battery to start out with.

 

Maybe you guys didn't read all of Brian's post?

 

Yes, I did, and it sounds as the battery is draining and probably needs replacement, a slow charge, trickle as they are called probably won't work as the battery is old. I suggested doing the battery test himself to double check the figure, it also could be an open circuit that is draining the battery, that happened to me once on a car i had. IMHO, a battery that sat this long is not going to take a charge, even if he drove it 100 mph all day with every conponent off. LUGNUT, you instructions are excellent, but this car needs an new battery IMHO.

 

Since the battery was replaced last year and it's been fiddled with by different people, I was thinking the cables could have become loose. The battery could be bad, but it seems unlikely since it's less than a year old and it's been checked out and okey doked by a shop.

He doesn't park it for longer than a couple of days at a time which shouldn't affect the battery life at all. On the other hand most batteries (non-deep cycle) can't take repeated chargings, especially from a "dead" condition, and will eventually refuse to take a charge. If the battery is bad it's probably from these repeated chargings.

He probably should go through the whole routine again to double-check everything, I guess. I'd still clean the posts and connectors first. If no success, then try another battery to see if it would do any good before going out and buying a new battery or even a cheap battery tester. My way's free and easy. Admittedly, it may not lead to the solution, but it may.