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  #1  
Old 05-16-2018, 07:45 PM
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Noise when starting

Noticed a metallic sound when starting our 85 300D.

Starter engages properly and engine starts right away. But this metallic sound is something new. Doesn't last long enough to determine where it comes from. I crawled under and had wife start car, but didn't help. No noise while running.

So, I guess I should prevent the engine from starting and try again.

Thinking it could be starter/ring gear noise? Or starter loose? But it spins engine and retracts without a problem.

Anyone had a similar problem?

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Old 05-16-2018, 08:07 PM
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Check bolts in starter.
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Old 05-16-2018, 08:33 PM
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Could be the starter loose, but more likely to be the Bendix binding, or the bearings in the clutch failing and causing a screech. If you hear it grinding, shut it down immediately, if the starter gear sticks in the flywheel teeth you can have some very expensive damage done.
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Old 05-17-2018, 12:42 AM
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Yes, when the alternator's fan blades barely hit its front bracket. BTW, did a newby engineer go overboard in designing that complicated bracket? Usually one would hear it slightly all the time, but could be just when starting. A pry bar quickly fixes the bracket.

Our 2002 Chrysler 3.8L van, would get a clunky noise when starting, and only occurred sometimes, i.e. w/ crank at certain positions. That was the final clue that the flex-plate was cracked (between engine and transmission). For a year before, I would hear a faint sheet-metal sound that I couldn't place, in fact suspecting the water pump at the front of the engine. Removed tranny and found the flexplate w/ radial cracks and cracked all the way around thru the bolt circle and had rotated 30 deg rel. to the crank. Surprisingly the engine ran fine like that, though the angle pickup marks are on the flex-plate (computer algorithm apparently adjusted). Common problem w/ the larger engine choice. But, I haven't read of flex-plate failures in our OM617 engines.
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Old 05-17-2018, 09:55 AM
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I will try and do some checking on weekend.

To prevent engine from starting when spinning it over, its been a while, but I seem to recall just tying the STOP lever up with a piece of wire. Any other way?
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Old 05-17-2018, 10:20 AM
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Quote:
Originally Posted by Graham View Post
I will try and do some checking on weekend.

To prevent engine from starting when spinning it over, its been a while, but I seem to recall just tying the STOP lever up with a piece of wire. Any other way?
Key out of ignition, jumper 2 big screws in terminal block passenger fender well. It will crank but not start because the fuel is shut off with key out.
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Old 05-17-2018, 05:46 PM
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Key out of ignition, jumper 2 big screws in terminal block passenger fender well. It will crank but not start because the fuel is shut off with key out.
Actually, on my car jumping either of the large screws with the smaller one spins the starter. Jumping the two larger ones does nothing.

However, engine does start!

Funnily enough, I did not hear any unusual noise from the engine bay. Need to re-check, but yesterday it seemed to come from under car.
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Old 05-17-2018, 06:46 PM
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Originally Posted by Graham View Post
Actually, on my car jumping either of the large screws with the smaller one spins the starter. Jumping the two larger ones does nothing.

However, engine does start!

Funnily enough, I did not hear any unusual noise from the engine bay. Need to re-check, but yesterday it seemed to come from under car.
Attachment 147760
If the key is not in the ignition and you jump the terminal block (big screw to small screw) and it starts, your shutoff switch in the ignition lock is faulty.
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Old 05-17-2018, 08:40 PM
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If the key is not in the ignition and you jump the terminal block (big screw to small screw) and it starts, your shutoff switch in the ignition lock is faulty.
Engine switches off normally using key. Maybe just enough pressure and fuel for engine to fire. But it did it twice.
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Last edited by Graham; 05-17-2018 at 08:50 PM.
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Old 05-18-2018, 09:29 PM
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Even with the shutoff valve working perfectly the engine will start and run until its vacuum pump has generated sufficient vacuum to shut itself off...or it might go into a state of low idle, governor fighting a weak vacuum pump at low RPM....
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  #11  
Old 05-18-2018, 09:34 PM
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Even with the shutoff valve working perfectly the engine will start and run until its vacuum pump has generated sufficient vacuum to shut itself off...or it might go into a state of low idle, governor fighting a weak vacuum pump at low RPM....
Thanks. Yes, I am sure that is what happens. If starting after car has been run for a while, then there is probably enough vacuum to shut fuel off.

I bought the remote switches I have (2 for some reason) for use when doing valve adjustments. But never did use them.
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Old 05-30-2018, 06:26 PM
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OK, I finally got back to trying to diagnose this problem. Found some concrete clues:

- When starting engine cold, I get this brief metallic noise just as the engine starts.

- When spinning engine without starting it, I get no noise.

- When engine is warm and I am doing short trips/stops around town, no noise.

Seems pretty clear that problem is that starter bendix gear is not disengaging quickly enough once engine starts.

I don't think I want to attempt starter removal. If I did, I might try and lube the solenoid/bendix mechanism and re-install. But if that does not work, have to R&R starter again

If I have shop do it, I will probably have recon Bosch starter installed. Then maybe work on existing starter which otherwise is working fine.

Before I go further with this, any other input?
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Old 05-30-2018, 09:08 PM
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The upper bolt on that starter can be a B E A R to break loose. Consider having a shop at least break that bolt loose if they are willing; but, you may want to leave the entire job to a shop with a lift. It is doable, but not an easy one mainly due to that upper bolt.

Good luck!!!
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Old 05-31-2018, 09:26 AM
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The upper bolt on that starter can be a B E A R to break loose. Consider having a shop at least break that bolt loose if they are willing; but, you may want to leave the entire job to a shop with a lift. It is doable, but not an easy one mainly due to that upper bolt.

Good luck!!!
Based on what has been posted, that was my plan.

If it was an easier R&R, then the starter could be checked out to see why it does not retract quickly enough.

Have been looking for replacement starters. Some sites show different one for 300D up to 84 and 85 on. There seems to be cheap Bosch remans and expensive Bosch remans. Need some help/work to find the right one!

Maybe shop will pull existing one and we can get it rebuilt locally.
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Old 06-18-2018, 08:26 PM
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Thought I had posted conclusion to this problem, but seems I did not.

Noise had gone away, but then came back and not just while starting. This actually helped diagnose problem.

I squirted some water on the alternator belts and noise went away briefly. This was repeatable. So I sprayed on some belt dressing and noise has now been gone for a few days.

Had this problem before but had forgotten. The noise was not a belt squeal, but more of a metallic sound. Could be some misalignment of the alternator sheaves. Belts are quite new, so I don't think I will fix it just now, seeing it ain't broke Shes just purring along again!

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