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Thom Pintello 05-27-2001 03:23 PM

My neighbor's starter on her 300TD would barely turn so I jumped into the problem with my usual reckless abandon. When I looked down at the starter from the top I could see that the top bolt was unbolted and the bottom bolt wasn't as tight as it could be. Thinking I had solved the problem I attempted to tighten both bolts with only a modicum of success. In the meantime I charged up the battery with my charger while working on the bolts. I should mention that we tried to jump the car with cables as well resulting in the engine barely turning for a one second and then resuming the clicking noise from the what I would presume is the starter solenoid. Even with a charged up battery we had the same result. My diagnosis is thus: I think she has a dead starter which will do about the same thing no matter how much voltage you put into it from any source. Any thoughts on this?

RG5384 05-27-2001 04:30 PM

not sure about the benzes, but on my gm when the cylinoid went the motor would catch for a little while and then you could here the starter spinning by itself(freewheeling). LIke i said mb starters could be differant though.

rudy 05-27-2001 05:47 PM

I agree with TXBILL, ...change battery, ...make sure you have the right cranking amps for that model. Also, ..check the brushes, ..maybe it need to be replace.

Jim Anderson 05-27-2001 06:03 PM

Check ALL the connections, including the grounds. If any one of them isn't perfect it won't start. I once jump started a diesel with a really bad battery with two cars.

Thom Pintello 05-28-2001 01:24 PM

Ok guys, here's where we stand so far. Today I took out her battery and put mine into the car. My battery was brand new in February so I know it's good. I got pretty much the same result, the engine turns ultra slowly and doesn't catch. Does this point to the starter as the culprit? Going back to my original post you'll notice that I said that the starter mounting bolts were loose, especially the top one. Could this indicate that someone else also determined that the starter was bad, attempted to remove it but bailed out when it turned out to be a more difficult job than expected? Thoughts anyone?

MikeTangas 05-28-2001 01:48 PM

Check out the link, about 3/4 of the way down there is a post that describes what and where to clean.

You might try tightening the starter and cleaning the described connections. Apparently the diesels are touchy about corrosion, probably due to their load at startup.

Thom Pintello 05-28-2001 09:23 PM

Thanks for the info everybody. Bill, I thought I'd start with the cheap stuff first and change the cables. I've got a new one for the positive terminal laying around which I never got around to using. I'll start there. If it isn't the cable then it's probably safe to say it's the starter but I'll go slowly before I make that conclusion. I think that there are other electrical anomalies that might point in the direction of bad cables as well. I'll keep you all apprised of the progress. Thanks.

can-do 05-29-2001 01:56 AM

Not wanting to presume anything
Greetings Thom,

This car you speak of, what year is it? Your problem seems all to familar to me when I first got my Benz. Slow cranking, then no cranking and definitely no start. Has this car been sitting around undriven for any amount of time? I'd do the following now, if this was my car. First, charge the battery, then take it to either a garage or Wal-Mart and have them put it on their tester to check for shorts or a dead cell, they do it free of charge. Your battery you pulled out of your car may only have a cranking amp of 550 or so and most diesels really need 750 and above to do the preglow and cranking necessary for ignition, mines a 850 cranking amp and 930 CCA. When you find out the battery is good and it's the proper amperage then try it again. I've been through the new battery that won't turn over a Benz diesel already. Jumping one of them is next to impossible as well unless the battery in the Benz hasn't really lost it's charge. The next item I would then look at is all the connections from battery to starter for perhaps a bad connection. Then when all else has been eliminated I'd consider the starter as one that perhaps has bad brushes or bearing causing a substancial draw on the battery or drag that is chewing up the amperage sent to it causing it to turn over extremely slow. If the car has been sitting a long while or cranked over quite a few times without success, I'd inject a little motor oil into the intake so you can lubricate the upper head and rings for a easier engine turn over and increased compression. After all has failed then either replace the brushes in the starter or spend the $150 for a rebuilt Bosch and go from there. I've done the whole senerial and ended up with a new battery that was underpowered and a rebuilt starter that was put in by someone else, paid too much as well. I've learned a lot since then and doing things in order saves money in the long run.


Thom Pintello 05-30-2001 02:53 PM

Ok, here's where we stand. I checked the connections on this vehicle and they are good. I even bypassed them with jumpers going directly from the battery to the starter with the cables. Of course the car didn't even crank. I then got a battery tester which indicated that the battery (750 CCA bought in November of last year) was good. I then used two batteries hooked together with a combined CCA of 1200 or so. The car started with this extra juice but refused to start with its own battery later. While it was running I checked the charging system and it was charging just fine. My original prognosis was the starter and I've changed my mind several times, what do you guys think? Thanks in advance.

MikeTangas 05-30-2001 07:53 PM

OK, it started using two batteries. Have you changed both battery cables? I know you stated earlier you were going to. That extra battery might have given enough *push* to get the juice through an internally corroded cable.

Thom Pintello 05-30-2001 08:11 PM

Yes, or at least I think so. When I attempted to diagnose the cables I used the jumper cables to supplement the already existing battery cables. In other words, I ran the positive jumper cable from the battery to the hot bolt on the starter and I helped the ground cable by going from the battery ground to another grounded part of the engine. Don't know if that's kosher but it seemed to make sense to me at the time. Maybe I should just change the damn cables and stop pussyfooting around here. Is this getting to me yet. NAH!!! :D

Thom Pintello 05-30-2001 08:19 PM

Yes Bill. It's turned into quite a puzzler but with a few anomalies as well. Remember that we still have a starter that is not cinched up all the way. Also remember that the battery I used yesterday (My own) may not have been fully charged or did not have enough CCA to make a difference. I have a few little tests to do yet but I think I'll just replace those cables first and see where the heck I stand. This is just so......interesting.

can-do 05-30-2001 09:24 PM

Still sounds familar
Greetings Thom,

This thread is sounding mighty familar each day. As was mentioned in an earlier post, was the engine cranking strongly using two batteries or just a normal crank? The question I have is whether you took the battery out and to anywhere to check for a bad cell? I've seen them come right off the rack new with a bad cell, hence no cranking amperage, only voltage. The other end of the deal is the starter where I was stumped on mine. It cranked slowly over regardless of new battery or freshly recharged old one. End bearings start going out in those starter causing it to draw even more amperage while trying to overcome friction and basically you lose cranking power real quick, and never achieve enough rotation to get compression where it needs to be for combustion. Changed out the starter and lubed the upper cylinder with oil, and a way we went and started right up. Haven't had a problem since the starter change.


Thom Pintello 05-31-2001 01:57 AM

Sorry guys, you're right. That's a pertinent bit of info. Yes, the starter did crank normally when I hooked it up in tandem with that 1200 CCA unit. And here's more...remember I told you that it wouldn't crank on its own after I shut off the engine? Well, the gal who owns the car got home and tried it and it started right up. Go figure. I still don't trust it though and suspect there is still something amiss with that starter. The saga continues....

Thom Pintello 05-31-2001 02:00 AM

can-do, I never did take the battery out to test for bad cells. I just relied on the battery tester that was telling me I had a good battery. I put a load on the battery twice before taking the reading too. Cheers.

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