The good news is that my SDL starts up usually on the first crank of the Starter Motor hot or cold, but on the way back from Florida the Starter motor sounds like it is still rotating after the engine has fired. I don't think it is still engaged with the ring-gear but it sounds like it is free-wheeling. It stops as soon as I release the ingition key, but is doing it every time now. I am concerned that it may develop into a bigger problem.

I did a search but found nothing relevant.

All ideas gratefully received

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1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown

I thought that the starter was supposed to stay engaged until the key was released, no? maybe I don't understand, or my SD is different

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Perhaps its my poor explanation.
In the past as soon as the engine fires the Starter Motor is disengaged and (I assume) the Solenoid cuts power to the circuit once the key is released from the "start" position.
Now for some reason when the engine starts the Starter Motor can be heard whirring away for a second or two as the key is released. I don't think the gears are still meshed otherwise I would have expected more of a graunching sound. This just sounds like an electric motor running freely.

My starter failed to release completely from the "flywheel" when it was really cold outside, and I got a noise whch may be like that described. Replaced the starter with a rebuilt unit and noise is gone, starts are very crisp also.

Kevin

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'85 300SD

The weird thing is that it almost seems like the engine is starting more quickly than before and that somehow this is 'catching out' the starter motor shut-off. I really don't think that it is remaining engaged with the flywheel as that is not the noise I am hearing. Its almost like the motor is on overrun, continuing to turn after the gear is disengaged.

This also started happening in the warmer southern climes before I got back to the cold weather.

My only thought about the easier starting is that I just switched to full synthetic oil (Mobil-1 15W-50) and maybe this is having some effect.

How easy is it to pull the Starter Motor for a check-out?
Can you purchase new brushes and if necessary a new solenoid, or do you have to replace the entire Starter Motor?

My starter isn't working and a search turned up this thread. For the past two days I had the same symptoms. Everytime I would start the car, the starter motor would disengage and spin for a second or two after the engine started. It's hard to describe but it felt like you couldn't release the key off the start position fast enough. Today, the starter spins but doesn't crank the engine.

Any ideas? I'll pull the starter and have a look see. I'm hoping it isn't my ring gear. Luckily, I parked it in my garage last night.

thanks
Dave

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1986 300SDL

(edit) it COULD be the ring gear. Hopefully not though, hope its just a sticking solenoid from brush residue build up, try squirting a lot of WD40 in it, you best remove that darned heavy cursed thing (can you tell, me and starter motors are enemies!? look into the opening with a mirror and see if teeth are missing on the ring gear. The starter can be activated using jumper cables. It should slap closed and the gear move into position when the solenoid is jumped to +

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

it sounds like a bad bendix, the mechanism which moves the small gear onto the big ring gear. could be a broken spring or such. maybe a kit available.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Yep, the pinion gear or "Bendix" (colloquially, it's not a true Bendix gear) can be replaced on an OM617 starter -- I did so about five years ago, and saved about 75% of the cost of replacing the entire starter. Last year the solenoid started acting up in hot weather, though, so I finally replaced the old starter with a Bosch rebuilt this spring.

The pinion gear unit has a fiber shim (looks like bakelite) bonded to the sleeve that retains the unit's heavy spring. I've been told that shim performs a sacrificial function. When it wears down, it protects the ring gear on the flywheel from damage by a malfuctioning pinion. The pinion stops working right, but it doesn't wreck the ring gear.

The theory makes sense to me, as the slipping pinion unit I removed from the starter had a worn-out fiber surface.

You can save a few bucks in the short-to medium term by replacing the pinion. Pulling the starter is such a bear of a job, though...how often do you want to do it?

Russ M

Since this thread re-activated I thought I'd give an update.
I had exactly the same symptoms and just recently had the Starter quit altogether. Unlike your situation where it spins but doesn't engage with the ring-gear, mine seized and jammed solid. I had stopped at a coffee shop and it restarted no problem, stopped for fuel 2 minutes later and no restart. The Starter was drawing power and the solenoid was kicking in but no rotation.

I purchased a Rebuilt Starter from Bosch and everything is fine now.

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1991 M-B 560SEL Arctic White/Grey 99,000 Miles
1987 M-B 300SDL Ivory/Palomino 229,000 Miles (sold but never forgotten)
2006 Volvo XC70 Blue/Beige
1999 Porsche Boxster Arena Red/Savanna Beige
1986 Porsche 928S Goldweiss/Brown