PeachParts Mercedes-Benz Forum - View Single Post - Hello all! new member, crazy story! melted battery post!

1911diesel · #1 04-11-2013, 11:55 PM

Ok, first off let me say hello to everyone, and that this will be a fairly long post, sorry. also i am not new to diesels or mercedes diesels even. i have owned 4 mercedes diesels now and this one, well its starting to make my head hurt...

Ok 85 300sd, paid 1200 bucks about 2 months ago, came with a spare mw injection pump, a spare tranny, (which i thought was awesome because the 82s tranny is slipping) and a spare vacuum pump. super clean body. one dent in the drivers front fender but no big deal. no real rust (ill post pics later its late and i work tomorrow) not much clear coat peal, tinted windows. most of the windows worked! lol (if you have owned many you know thats a big deal!) sun roof worked! the engine (i was told) was just changed because the old one snapped a timing chain. (the spare parts came from the 81 300d that was the parts car.) oh it needed a head light and a break light and some other little things... so i was told... well i been buying and swaping and trading cars for a long while now, i know there is always more then meets the eye or is said when buying a used car. so i kinda figured there was more but it was cheap and super clean! (the 82 i like to call my soon to be parts car...windows work when they want to, gauge cluster works when it wants to, sun roof does not work, body is kinda rough, paint is fading bad, tranny slips but it runs great! oh interior is kinda rough.) so we picked it up knowing i was going to work on it. well first things first, the alda was broken... now its removed. (oh by the way it smoked black at idle before the alda was removed im still trying to figure that out...) the waste gate was stuck open, just a little. made for slow boost response. now its working properly. i think it needs ball joints. not sure havent gotten that far...lol but the thing that im having the most problems with, is this electrical demon. i know it has to be a ground somewhere.

Ok problem i need the most help with at this moment, where to start...lol well it has killed 3 batteries now. the most recent battery it melted, yes i said melted the positive post. the battery before that it just killed the cells, ( 24 hour 2 amp charge and still not taking a charge battery was replaced, the battery that is melted was this ones replacement) and the one that came with the car died about the second or third time this problem struck. Ok the problem is that when we start the car, or attempt to start the car, sometimes not always, only once every three days or so, it will completely discharge the battery. sometimes it will start, sometimes it wont. if it starts and the battery is discharged nothing electrical will work. if it doesnt start, most of the time the battery would come out of the discharge with a slow over night charge. now the real crazy part is that sometimes, the seats will move on their own! while she is driving! i found one ground problem, it was the bottom starter bolt, that wasnt threaded to the starter. It is now tight and that ground is tight. I thought i solved the problem with the starter ground. this last battery that melted, is the result of my assumption. i have had similar problems with my ford. bad starter solenoid killing batteries, and a bad starter armature grounding itself and killing batteries, but nothing ever this extreme. am i safe to think i should be looking for a failure some where between the starter and battery and the main grounds. with the amount of amperage it took to melt the battery post it has to be a large gauge wire grounding. otherwise i would imagine it would have been the wire fried and not the battery. or fuse or solenoid or something else would have failed before that point. Oh and it only discharges the battery when trying to start. the alternator still puts out 13.7-14 v.

Im starting to think the car just doesnt like her... it doesnt do any of that when im driving it or starting it. just my ol lady.