This morning I purchased an Ultima starter from O'reilly's and installed it. I know, I know. What was I thinking? This is my only car and I was in a pinch.

After installing the starter, I started the car 4 times within a minute, no problem. I go into the house for lunch, and an hour and a half later go to start it and get nothing from the turn of the key. I jump it at the fender terminal and get nothing, run a wire directly from the battery to the starter and get nothing. What's going on? Bad starter?

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'81 300SD

Didn't you just replace the starter recently (within the last 6 months)?

Found this Is there a sign that your starter is on the way out?

Is this the same car?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I replaced that starter with a spare that I had, but it would occasionally hang up on the flywheel after it turned the engine over. Then I replaced that one with a used one that Sixto had gathering dust in his garage, and that one was fine until the solenoid started sticking. I finally bought a freshly rebuilt, but that looks to be a bad choice. I'll check my ground connections.

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'81 300SD

That should have been done 4 starters ago! It is unlikely 4 starters in a row give intermittent starts.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I disconnected and cleaned all of the ground connections and still no crank with the O'reilly's starter. I installed the old starter that would occasionally hang up on the flywheel and it cranked first try.

The failures of the previous starters were all different, so I don't think that there is an ignition issue.

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'81 300SD

Bench test the O'reilly starter. Is is dead? I have a suspicion it is not. Since cleaning the connections where they are bolted on does not seem to solve these long standing intermittent problems, you have to go further. I think I have mentioned this a few months ago in your other posts: You need to cut open the heat shrink and inspect the crimps of all the power and ground leads in the starter circuit. Wire brush and use plenty of flux and solder all the crimps with a 100 W iron with a fat tip. Or buy all new cables. Don't know if they are still available from the dealer.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I got my money back from O'Reilly's for that Ultima starter.

I took a long drive up in the hills and got the engine nice and hot after installing the spare starter I have that occasionally hangs up on the flywheel. After parking the car and waiting a minute, I turned the key and it fired right up. I'd like to put a new solenoid on the other starter that was failing when hot. Can anyone recommend a brand? Are there other parts of the starter that fail after getting heat soaked?

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'81 300SD