Question, Assuming the batttery is just fine, what could cause my diesel to go dead? Dead as in lights don't work, engine won't turn, nothing?
A breif history, 1980 300d, tried starting after sitting for a few months. Battery was to low to turn over fast enough to start. Neighbor hooked his truck up to jump start. Tried to start and starter got stuck, lights went out in dash with the engine still turning over. Had to disconnect negetive cable to stop. Since then, DEAD. I've looked at the cables and they seem fine. I feel it must be somthing really simple. Or at least I hope so. Any ideas? Thanks, Vin

I suggest, unless there is more to the story than you wrote... that you take the battery out and have it checked.... or at least put it on a trickle charger overnight....
Then really check your cables, the ground to the engine and body, then tell us what it is doing....

Thanks, I'm going to remove and clean the cables and ground straps and try a different battery. It seems odd that nothing works. Just stopped. Not even the dome light works. I'll go check and clean. Oh, I have checked all the fuses that I am aware of, and they are all fine. vin

I checked and cleaned every strap and cable I could find. Also had battery checked at local parts shop. They said it was fine. Still nothing. Is there some kind of master fuse or somthing of sorts? Until that time when the battery was low and could not turn over engine fast enough to start, the car always started right away and I have not had any electrical problems that I was aware of. Any ideas? vin

You can check your fuses... but total non electricity sure sounds more like cable connections if your batter is good....
You should make a tester.... a little 12 volt light and two wires... then start at the battery and check each place you can touch... when you no longer get light then you know where to concentrate....

Did you take the straps and cables OFF and clean the bottom side and the place they are touching ?

Sometimes corrosion can be so bad UNDER the rubber covering of a cable.... you may need an ohm meter to measure resistances...

Leathermang, Yes, I did take the cables off and clean them. They all looked good even before I cleaned them. The car is just acting as if there were not a batttery hooked up at all. I believe that even if the connections were not good enough to let enough voltage through to start the car, there might be enough to operate the dash or dome light. Do you know of anything that could have "blown out"? I'll have to wait until tonight to fiddle with it again. thanks, vin

I think you may have a broken battery post... internally.... sometimes it will show power when it is not being pulled a certain direction by the battery cable....

Batteries are fairly simple and easy to test if you know how, but I'm afraid that most professionals don't. At the basic level you need to do a voltage check and if it below about 12 volts, it should be charged before load testing. During the charging and after charging the specific gravity should be chevked. If you have one dead cell, the battery aint no good. Once the gravity tester says the battery is fully charged, you need to load test it to see if it will handle the load. There is much more, but these are the basics. I would also suspect a starter may be hung up from your description. Make sure the shop checks your battery like I suggested. Also to jump a diesel, you need good quality jumper cables. Those crap cables that sell for a dollar three ninety eight won't cut it.

Peter

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Auto Zentral Ltd.

Finally had a chance to work on the problem again. Took battery to shop and they said it was good. So I took it to Autozone and they hooked it up to a cool machine and said that it was bad because it could not hold a charge. Bought a new battery and car started right up. I knew it had to be somthing simple. If the first auto shop store I took it to tested it correctly I wouldn't have had this problem and they would have made money by selling me a new battery. thanks for your help. vin

vin, did you get a group 49 battery at autozone? if so can you post the price if you don't mind, and any warranty info?
thanks

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

Been in this business 30 years and can't count the times the simplist item in the car, the battery is misdiagnosed. That's why I posted the above. Anyway, glad you solved your problem.

Peter

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Auto Zentral Ltd.

I just bought a group 49 battery at Autozone last week. It was $65. 7 year warranty (2 year free replacement).

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'81 300TD Wagon 355k (Miss Diesel)
'83 300SD 180k
'84 500SEL 190k (Parting it out)

that sounds like an excellent deal. understand that the autozone
batteries are made by johnson controls - under the name duralast ?? anyhow same as sears die hard,
and a lot less $$.

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

I went into Sears before Autozone; $105, and all of their batteries are now maintenance free...

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'81 300TD Wagon 355k (Miss Diesel)
'83 300SD 180k
'84 500SEL 190k (Parting it out)

We've been down this battery road before. Autozone sells their batteries for $65.00, because they know what their batteries are worth. Autozone has to go to some battery to make their batteries , because they don't have the facilities. They go to Johnson Control and ask them to make a battery for them. They say this is how much we can spend and be able to make a profit by retailing them for $65.00, and JC says fine. We'll make the best battery that we can for that much money and still make a profit ourselves. Throw in another twenty bucks, and we'll make an even better battery. I'll take an Interstate anyday. You can't beat em.

Peter

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Auto Zentral Ltd.