I have a Mercedes 300D that my parents got for me so that I had a car to get to and from work in. It’s only a few miles from my house, and this car was under the care of someone who was rebuilding it. It has 200k miles, but the engine and transmission work perfectly and it doesn’t even have any fluid leaks. My previous problem was the battery, but now a more serious one has come up. The car came with replacement parts in the trunk that I will be putting in as time goes by, but there was also the original battery which had been refurbished. I tested it with my multimeter and it was showing a good, healthy 12.6V. Since the other battery was refusing to charge (cheap Wally-mart piece of junk) I decided to give the old battery a go. I switched it out and started the car beautifully while jumped to my wife’s car. I took it down to fill the tank and then tried to start it again. When I hit the start button (the key assembly was bypassed before I got the car with a push button on the dash) it made a metal-against-metal screech which sounded really bad but was quieter than the engine itself would be. I then pushed the button again and I got dead silence. Not even a solenoid click. I tried switching back to the half-charging battery, but still no turning or solenoid sound. I then tried starting while jumped with no effect. The interior is powered and the seat belt warning buzzer is nice and strong (it sounds weak if the battery is near dead). When I started the car earlier while jumped the starter was very strong and vigorous, more than I had heard it be since I got the car.
What did I do to my poor mercedes? My first layman guess was a fuse but the starter doesn’t connect to the fuse box at any point nor is there a place for a fuse in the box for the starting system. It is currently waiting at a gas station for me to get off work and try to diagnose it. Could there be an inline fuse in the wire to the starter? Could something have been wrong with that old battery to the point where it blew out some component of the starter, like the solenoid? Could I have busted a tooth off the starter or flywheel and got it jammed? But then I would still hear the solenoid, right? I am going to go and try to short the starter to the + battery terminal with my jumper cables to see where the disconnect occurs, and I’ll see if I can’t bypass the solenoid with the jumpers and see if that solves the problem. Maybe turn the starter by hand a bit to free anything jammed? Any suggestions would be greatly appreciated!
Many thanks!
-Tycho
200K miles…Run-out Benz’s are money pits…Start saving up for a new starter…
“. Since the other battery was refusing to charge (cheap Wally-mart piece of junk) I decided to give the old battery a go. I switched it out and started the car beautifully while jumped to my wife’s car. I took it down to fill the tank and then tried to start it again. When I hit the start button (the key assembly was bypassed before I got the car with a push button on the dash) it made a metal-against-metal screech which sounded really bad but was quieter than the engine itself would be. I then pushed the button again and I got dead silence. Not even a solenoid click. I tried switching back to the half-charging battery, but still no turning or solenoid sound. I then tried starting while jumped with no effect”…
Goldwing, thanks for the link! What a useful website! I got the problem resolved, thank you so much for your advice.
@TychoBarney - what was the problem, exactly? That’ll help us if it comes up again with somebody else.
It was a problem with the car my father in law was trying to jump-start me with. I stayed in the parking lot of that gas station for a couple hours making sure each electrical component between the battery and the starter was working properly. I noticed that the starter solenoid had actually been previously bypassed by the starting button on my dashboard. After determining that nothing between the motor and the battery was faulty, a local police officer came and we jumped my car again. This time it worked, so by process of elimination it must have been the jumper connection I was using earlier that was not working. Maybe I didn’t get a firm enough connection to my father in law’s battery or something, but with the officer I double checked with my multimeter that I was connected before hooking up my battery. I’m going to keep that thing in my car from now on, just in case.
Why didn’t you include this information in your FIRST post instead of playing “Stump The Chump” with us??
uh, because I didn’t KNOW the answer when I wrote the first post?
Sounds like the first time you pushed the button the starter ring gear just didnt meash with the flywheel properly…Happens sometimes. Then the next time you pushed the button…Maybe your connections to the solenoid just were dirty and it didnt work. CLean all of your electrical connections associated with the starter and your push button…wouldnt hurt to clean and grease and tighten ALL your battery connections as well…that is a MUST in every vehicle but especially so in a Diesel. I dont think you have any major issues. Glad to hear your are back up and running…
Convert that Thang to run on Vegetable oil man…The 300D is the poster child for Veggie burning… I have put over 80K on my VW Golf TDi…using Vegetable oil FREE Veggie Waste oil. Thats a lot of FREE miles to drive… Its fun too 
Good luck.
“uh, because I didn’t KNOW the answer when I wrote the first post?”
Read your post…Sounds like one, unbroken incident to me…Unless you were posting from the disabled Benz sitting in the station parking lot, waiting for someone with a set of decent jumper cables to come along…Whatever, sounds like you are back in business…