W124 Loud metallic machine gun noise on start-up

White230CE

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Hi all,

When I turn the ignition on my W124 230CE, there is a very loud metallic noise like a machine gun, as the engine coughs into life. It's been present since my exhaust started deteriorating about 6 weeks ago, and I had assumed it was an exhaust problem. However, I now have a new exhaust and the noise continues. Also, I heard it for the first time from outside the car, and it sounds terrible - worse than when I am sat in the driver's seat.

A friend of mine who has heard it thinks the noise might be the starter pinion grinding with the flywheel, and the fault could be the solenoid, the starter motor or the flywheel.

Would appreciate urgent advice please. I'm assuming that continued use will cause more damage?

Many thanks
 

brandwooddixon

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It is most likely down to the solenoid not managing to engage the pinion and flywheel correctly.

This could be down to a low battery voltage or just plain old wear and tear.

Try placing a second battery in parallel to your own e.g. jump leads to another car. If the noise doesn't occur when you try to start the car then your battery is on it's way out.

Otherwise it is likely that the solenoid is sticky. Depending on how technically minded you are you could have a go at servicing it yourself (cleaning and regreasing parts) in which case you could replace the brushes whilst you're at it.
 
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White230CE

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Thanks guys. The battery is pretty new, but will check, as that would be the easy fix. I will take a look underneath to see how to get to the solenoid and starter, and report back.

If anyone has a 'how to' to remove solenoid and starter motor, and how to clean strip and overhaul the solenoid, I would be very grateful for a copy.

Thanks
 

television

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I think that I would change the starter rather than try and fix it, I can find you the changing it information
 
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White230CE

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Thanks Malcolm I would be much obliged for that help. In case you need it my email is ray.ng@vodafone.net. Can I please clarify that you mean change the solenoid? Or do you mean change the starter motor including attached solenoid?
 

Number_Cruncher

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If the battery and connections and supply from the switch, are all OK, it's possible that the hlding coil in the solenoid has failed. After checking battery and connections and the supply from the ignition switch, I would be tempted to either;

- fit a reconditioned starter
- remove the starter and have it repaired by a local reconditioner [it used to be the case that every decent sized town had one, but, I suspect they are thinner on the ground these days]
 

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If the battery and connections and supply from the switch, are all OK, it's possible that the hlding coil in the solenoid has failed. After checking battery and connections and the supply from the ignition switch, I would be tempted to either;

- fit a reconditioned starter
- remove the starter and have it repaired by a local reconditioner [it used to be the case that every decent sized town had one, but, I suspect they are thinner on the ground these days]


Those were the days when every town had one,,you could buy carburetor jets and gaskets, bearings and brushes.

Its worth checking the earth strap, thats the big one,,it could be that the starter is pulling to much current,,and this will cause the solenoid to do that
 
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White230CE

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Thanks once again to all for the advice.

This is now at the limits of my learning curve. In order to understand what you've advised, and to know what to ask next, I need to take a look and have a fiddle. Plan: I will attempt to pilfer the starter motor from the donor car (which does not make any untoward noises on starting). If I succeed in doing that, I will next try to put it on the cannibal, and see if the problem is solved. If so, I will then concentrate on the removed starter and go from there, no doubt with more questions. If not, I will report back, also with more questions.

Fingers crossed. :D
 

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I have sent the removal instructions,,its simple
 
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White230CE

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Instructions received thanks Malcolm.

I've had a good poke around underneath, with the instructions as a map. Also took off the air filter unit to allow a better view from above. I have identified the starter motor, the bolts attaching it, and the wires attached to the solenoid, and indeed, it looks simple, Malcolm - far less daunting than I first thought.

The car is on two axle stands and my problem is access:

I can get to the bolts attaching the starter motor. No problem.

With the steering fully locked left, and by lying with my head about under the wheel arch, with a torch, I can see and touch the two wires attached to the solenoid - one by a nut, the other by a screw.

I can get to the nut which attaches one wire to the solenoid. I reckon I can also re-attach the wire with that nut.

The problem is the remaining wire held on with the screw. My hand reach and positioning are limited, and I can't get a stubby screwdriver into the right place, and even if I could, turning it in a screw that may be corroded will be a problem. And if I get as far as removing the screw, re-attaching the wire with a new screw is going to be difficult.

I've tried reaching it from above, but I am blocked by an inlet manifold pipe. There is a small gap next to the pipe, but there is a three-pin Bosch 'thingy' in the way. I've unplugged the wire that plugs into it, but not sure how to, or if I should, remove the Bosch. If I could, I might conceivably get a long screwdriver in to reach the screw, but re-attaching from above seems impossible.

How do you guys do it?!!!! :confused: Is it possible to unbolt the starter motor, draw it down with the wire and then detach the wire?
 
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White230CE

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Success! Starter motor removed. :D

Had to unbolt it first, ease it down and let it dangle, to get at the wires. Also had to lock the front wheels in the other direction (ie turned full right) which gave better access where I needed it.

Nut holding wire was quite easy to undo. Cross-head on screw holding wire was partly stripped, but just got enough grip to turn it.

Pinion teeth were knackered, so I hope the flywheel teeth aren't.

Getting a new Bosch unit from GSF tomorrow. Will fit and report back on the outcome.

Thanks pnce again for everyone's help.
 

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It sounds good for starters :D:D
 
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White230CE

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The starter motor is on! Having been through the learning process of taking it off, putting it back on was quite easy. Gone is the rat-a-tat-tat, and the engine now purrs into life when I turn the key. :D:D:D

This is a DIY milestone for me, and my thanks and appreciation to all of you for helping me reach it!
 
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White230CE

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I should add that reaching this milestone was not just about this specific job, but all the jobs that preceded it, which built up my knowledge, skill and confidence. My thanks and appreciation are to everyone who helped on all the jobs. Until I joined this forum, my car DIY was confined to filling vehicles with petrol, air and wash-wipe. :Oops:
 

kth286

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I should add that reaching this milestone was not just about this specific job, but all the jobs that preceded it, which built up my knowledge, skill and confidence. My thanks and appreciation are to everyone who helped on all the jobs. Until I joined this forum, my car DIY was confined to filling vehicles with petrol, air and wash-wipe. :Oops:

A really excellent 'thank you' - thank you.
 

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