E320 Cdi Alternator

[Tim Green]

I have a 2000 E320 cdi estate, done about 60K miles. When driving at night, I occasionally see the lights go very bright for about a second, then go back to normal. This happens rnadomly about every 10 to 15 mins, with no apparent reason. Merc at Oxford said it could be the alternator which costs about £1500 to replace. Is this true? Could something else be at fault? There is no obvious fault with the alternator.
There is evidence that that the battery may be not too good, because after cold start sometimes the cruise won't work, but always works if I stop engine and re-start. Any adivce useful
Rgds, TG

 

[television]

I have a 2000 E320 cdi estate, done about 60K miles. When driving at night, I occasionally see the lights go very bright for about a second, then go back to normal. This happens rnadomly about every 10 to 15 mins, with no apparent reason. Merc at Oxford said it could be the alternator which costs about £1500 to replace. Is this true? Could something else be at fault? There is no obvious fault with the alternator.
There is evidence that that the battery may be not too good, because after cold start sometimes the cruise won't work, but always works if I stop engine and re-start. Any adivce useful
Rgds, TG

First change the control module on the rear of the alternator, it cost £20 and only held in with 2 screws.

If your Battery is the original I would change that. I can give more details later in the day.

Malcolm

 

[jberks]

certainly sounds like the regulator.
It really irritates me that dealers don't tell customers the alternatives.
Alternators almost never fail. Regulators go and cost £20 as Malcolm says, or the bearings go and cost maybe £50 to fix - but the rest of it will last forever. £1500 outrageous!

Do yourself a favour, find a decent local indie. You really shouldn't be taking a 2000 E class to the dealer for repairs - you get the worst service for the highest price. Makes absolutely no sense. Servicing is a different matter if your tin work cover is up to date.

 

[television]

Let me just come back here now with a bit more time.

The battery could have an intermitant parcial short that for the best part stays in the short circuit mode, the out come of this is that the running voltage of the car could be reduced from the normal 13.8 volts down to say 11 volts, if the fault cleared itself in the battery then the lights would look brighter than you are used to.

As Jberks you do not replace the alternator.
go to an Auto electrics service center, Not MB Look in your yellow pages for a Bosch one.
its a simple voltage check will tell all.

Malcolm

 

[Tim Green]

Thanks for your notes
The MB chap said that the alternator was a special water cooled affair and was only accessible after removal of the turbo, etc. As an electornics engineer, I do understand the basic but not the detail of what's involved with this particular car. I think I should change the battery anyway and see if that helps.

 

[television]

Tim,if the battery is the original, then do change it for a good brand, not house name,.

A good easy check is to stick a voltmeter over the battery first thing in the morning,before you start the car, anything under 12volt then it is the battery.

Regards from an electronics engineer, Malcolm

 

[Parrot of Doom]

A £1500 alternator?

Does it use oxygen free silver-plated copper windings?

 

[television]

A £1500 alternator?

Does it use oxygen free silver-plated copper windings?

Come on you do get free coffee when you are waiting


Malcolm

 

[Hibbo]

A £1500 alternator?

Does it use oxygen free silver-plated copper windings?

But Parrot it's a Merc so you must take it to a Merc dealer and let a Merc 'tech' fit a brand new Merc alternator. If you don't want to pay £1500 for a new alternator (because Merc don't sell regulators) then you shouldn't have bought a Merc.

 

[OlafMaxwell]

If you have a main dealer in an area where there are a lot of older Mercs very often they know the fixes. But, they are rare. Alternators can be repaired and reconditioned by good specialists, many of the components within can be replaced. Just may take a day or two longer than simply throwing £1500 at a new one. I must say that happened a friend of mine, they put a new alternator in after insisting it was the cause of an electrical problem, turned out it was the battery. He made the main dealer get the old one back into the car or else refund him his money.......he got his money back. The £1500 is a massive figure though.

 

[television]

If you have a main dealer in an area where there are a lot of older Mercs very often they know the fixes. But, they are rare. Alternators can be repaired and reconditioned by good specialists, many of the components within can be replaced. Just may take a day or two longer than simply throwing £1500 at a new one. I must say that happened a friend of mine, they put a new alternator in after insisting it was the cause of an electrical problem, turned out it was the battery. He made the main dealer get the old one back into the car or else refund him his money.......he got his money back. The £1500 is a massive figure though.

Hi olaf, it never ceases to amaze me of how much people will give MB for not fixing the fault.

I do not know of any other trade where this goes on, thousands of pounds for not fixing a thing, they keep the parts that they took off´

Malcolm

 

[carabind]

It's not just MB who do this. I had a Ford brand with an internitttent fault, and it went into them 4 times for them to fit different parts before they cured the fault. No aplogies, they were more concerned wit getting paid
(it was a compnay car and they could see grief on the horizon - ie my company getting 4 bills within a month for the same fault)

 

[type49]

Thanks for your notes
The MB chap said that the alternator was a special water cooled affair and was only accessible after removal of the turbo, etc. As an electornics engineer, I do understand the basic but not the detail of what's involved with this particular car. I think I should change the battery anyway and see if that helps.

Yes it's water cooled & a bit of a pig to fit, although I've never seen anyone remove the turbo to do so. I think it is about 2-2.5 hour job to remove /replace. The regulator pack may not be accessable without removing the alternator (petrol ones are but I've never done a diesel regulator, only changed complete unit due to being noisy after flood damage). Not a job to be done at home unless you can get right underneath it + get covered in coolant - nice! Another poss problem is the battery control module, mounted on the rear panel with the main battery earth bolted to it. This unit does can receive software updates & is prone to failing. There is also a charge rate relay under front scuttle trim near wiper which needs checking + a wire to this relay fails in the area of the NSF A pillar behind the starter battery (yes you have 2 batteries on this car).
Good luck!

PS how much is an alternator on its own, labour shouldn't be more than £250-£300.

 

[Bargain Bucket]

2 batteries? Oh great. So where exactly is the starter battery on a MY2000 W210 E320 CDi? And how do you know which battery needs replacing when the car declares "Voltage low"?

 

[Blobcat]

2 batteries? Oh great. So where exactly is the starter battery on a MY2000 W210 E320 CDi? And how do you know which battery needs replacing when the car declares "Voltage low"?

W210 only has one battery beneath the rear seat. There are two white clips below the seat squab at the front on each side.

 

[type49]

2 batteries? Oh great. So where exactly is the starter battery on a MY2000 W210 E320 CDi? And how do you know which battery needs replacing when the car declares "Voltage low"?

Ooopps, sorry, thought it was a 211. Forget about the battery control module + the relay near the wiper + the wire, oh & the second battery. I'm not helping much am I???

 

[television]

Ooopps, sorry, thought it was a 211. Forget about the battery control module + the relay near the wiper + the wire, oh & the second battery. I'm not helping much am I???

You are one of the best helps that we have on the forum, when a thread gets too long it gets harder to follow unless in it from Day one.

Malcolm

 

[Bargain Bucket]

Thanks for clarifying the situation. Mucho appreciatedo.

Ooopps, sorry, thought it was a 211. Forget about the battery control module + the relay near the wiper + the wire, oh & the second battery. I'm not helping much am I???