C63 AMG starter motor fuse keeps blowing...

[serkie]

Hi All,

Hopefully this is the right section...

I've owned my C63 AMG Estate for just over 2 months now and everything has been generally excellent. Car was purchased from Mercedes Benz Direct.

In early July the car wouldn't start after being sat on my drive for 2 days. Upon investigation by Mercedes Roadside assistance it was discovered that the starter motor fuse had blown. Chap replaced the fuse and all was well. He advised that should it do it again to take it to Mercedes.

Few days later again after the car had been sat for a day the car wouldn't start and the fuse had indeed blown again. This was during the wet start to July so I immediately thought this was something to do with the rain.

Car was taken to Mercedes and no obvious fault could be found although I was told that some conduit and connectors that may have allowed water ingress to occur had been repositioned and sealed. Great I thought, car was subsequently fault free for 4 days but again after being left for almost 2 days the car wouldn't start and the fuse had blown again.

Car is back with Mercedes now and I'm starting to think that perhaps when the car isn't being used for a period of time some kind of resistance is occuring in the starter motor which upon start is drawing too much initial current blowing the fuse. As the motor has been freed up replacing the fuse cures the problem.

I'm pushing for a new starter motor assembly under warranty but the dealer is saying that if no fault can be found no claim can be raised.

Has anyone else had this or a similar issue?

Cheers,

Serk

 

[Simon_M]

Never heard of it. I would also push for a new starter motor.

 

[The _Don]

+1 Never heard of that fault dont worry car is under warranty will be fixed foc.

 

[serkie]

+1 Never heard of that fault dont worry car is under warranty will be fixed foc.

You say that but this 2nd investigation is chargeable if they again find no issues.

 

[The _Don]

Refuse the charge get a loan car tell them to notify you when it is resolved obviously there is a fault present.

 

[lxi]

I know it's a pain but one way they cannot shirk their responsibility is next time it happens, call Mobilo & get it trailered to the dealer - that way they see it with the blown fuse.

Having said that, I don't see any basis on which they can charge - they have failed to find the fault and with all the diagnostic kit they have on hand they should be red faced about that, so push them to find the fault & not come back until.

 

[sinewave]

Could be a dodgy Alternator of AC Compressor that's starting to seize?

 

[serkie]

I know it's a pain but one way they cannot shirk their responsibility is next time it happens, call Mobilo & get it trailered to the dealer - that way they see it with the blown fuse.

Having said that, I don't see any basis on which they can charge - they have failed to find the fault and with all the diagnostic kit they have on hand they should be red faced about that, so push them to find the fault & not come back until.

Yep this is what I'm thinking of doing if they don't fix it this time.

 

[serkie]

Could be a dodgy Alternator of AC Compressor that's starting to seize?

Mobilo guy told me he's only ever seen one other AMG do this however he see's it a lot on the E Class.

He claims that the starter motor can suffer from binding with age. The fix he thought was to strip, clean and lubricate the assembly and refit. If that didn't fix it then a replacement starter assembly was needed.

I've told MB all of this however all they wanted to do was put a hose pipe over the car and see if the fuse blew.

 

[reason42]

How old is the car?

 

[serkie]

How old is the car?

'58' Plate bud.

 

[brucemillar]

Mobilo guy told me he's only ever seen one other AMG do this however he see's it a lot on the E Class.

He claims that the starter motor can suffer from binding with age. The fix he thought was to strip, clean and lubricate the assembly and refit. If that didn't fix it then a replacement starter assembly was needed.

I've told MB all of this however all they wanted to do was put a hose pipe over the car and see if the fuse blew.

Putting a hose over will prove nothing, apart (possibly) from what they already know. i.e. The starter fuse blows when the car get's wet or is stood up for a few days.

I suggest that they put the hose over themselves and wash out the fluff between their ears. Write to MB UK and tell them what is going on here. State very clearly that you are not happy with the feeble attempts at diagnosis or repair.

 

[serkie]

Just back from the dealer with the car.

No obvious faults found but they have agreed to order up and fit a replacement starter assembly from Germany under warranty.

Unfortunately I was hoping to come back with some useful information to what the problem is related too but alas a new part will hopefully cure the problem.

Cheers,

Serk

 

[The _Don]

Good result.

 

[michael8554]

Possibly a shorting winding on the starter motor.
On a warm engine the starter may quickly spin past the shorting section without blowing the fuse.
A cold engine is slow to turn over and blows the fuse before spinning past.
However, there might be other components on the same fuse that could be at fault.

 

[serkie]

Just thought I'd update this thread.

Starter motor was changed under MB warranty 6 weeks ago and all has been well since. Although no specific fault was found I can only assume the issue was being instigated at the starter assembly.

Good service all-round by MB - Greenoaks (Ascot).