CL500 Alternator / Voltage fluctation issue

[CL500Wizard]

Hi All

First of all, thanks for a great forum, loads of information and a good bunch of people

I've got a 2000/1 CL500 and all the lights (interior, brakes) are pinking at idle but get brighter when revving plus there is noise from the alternator - sounds like the bearings. Looking at the belt movement, all the pulleys look ok to the naked eye. Belt looks in good condition overall.

After a bit of reading, I'm going to do the before and after ignition voltage readings (with lights and sat nav etc off and on in various combinations with engine running)

I also read on the net that the failing Bosch voltage regulator in the alternator can cause this fluctation problem but with the bearing type noise I suspect it would possibly be more involved than just changing the regulator which looks like a straight forward job.

Just a few questions if you don't mind:

1. Is the alternator refurbable? If yes, what's the best approach? DIY - special tools required? If not, there are a few Bosch service centres not far, any highly recommended in West London area (heathrow and nearby)?

2. How does one check the belt tensioner? (where is it )

3. Should I hold on from a 400 miles return trip at the weekend? Doing about 20-30 miles daily on an average 40 mph speed.

3. At idle, there is a light engine vibration which is a lot less since the air filters change and MAF cleaning with Electric Contact cleaner from HellFrauds (thanks Parrot of Doom: http://forums.mercedesclub.org.uk/showthread.php?t=18298). MPG has improved as well, and there is finally steam and water coming from the exhaust!

4. Finally, is there a Service Manual (I love those, bedtime reading!!) available? Other than the above, I'd like to check the sparkplugs as well (they were changed at 68 miles, car is now 93K miles) and anything else which is easy to check from the ignition and air side of things plus the oil and filter change - pretty good at following the manuals and like DIY as much as possible on my cars.

This is my first Merc (& German too), being a Honda Nut for some years I've usually worked on all my Hondas myself (engine rebuilt once too which took a few weeks :lol but with the Merc I don't know yet how often I'd need to go to an Indie or MB; guess that will become apparent with time. However, for starters if you can direct me to a guide on changing/checking/refurbing the alternator and the tensioner it would be much appreciated.

Thanks in advance for any help.

Arslan

 

[jibcl500]

Arslan

I think you need to find a specialist and have them take a look at the car, sooner rather than later..

jib

 

[television]

Hi All

First of all, thanks for a great forum, loads of information and a good bunch of people

I've got a 2000/1 CL500 and all the lights (interior, brakes) are pinking at idle but get brighter when revving plus there is noise from the alternator - sounds like the bearings. Looking at the belt movement, all the pulleys look ok to the naked eye. Belt looks in good condition overall.

I doubt very much that it is the alternator, as it is the idle assembly that normally make the noise, even if the battery is fully charged, the lights can brighten when the engine is speed is increased due to the voltage increase from 12.5 volt to 13.8volt

After a bit of reading, I'm going to do the before and after ignition voltage readings (with lights and sat nav etc off and on in various combinations with engine running)

I also read on the net that the failing Bosch voltage regulator in the alternator can cause this fluctation problem but with the bearing type noise I suspect it would possibly be more involved than just changing the regulator which looks like a straight forward job.

As above, I doubt if it is fauly

Just a few questions if you don't mind:

1. Is the alternator refurbable? If yes, what's the best approach? DIY - special tools required? If not, there are a few Bosch service centres not far, any highly recommended in West London area (heathrow and nearby)?

If it was faulty then the Bosch service center is the best way to go, the alternator either works or it does not, and yours is working, the battery lamp would be on if it was faulty, and if 1 diode had gone down, it would be glowing dimly



2. How does one check the belt tensioner? (where is it )
http://www.detali.ru/cat/oem_mb2.as...GA=722.633&CT=M&cat=07N&SID=20&SGR=045&SGN=03

3. Should I hold on from a 400 miles return trip at the weekend? Doing about 20-30 miles daily on an average 40 mph speed.

3. At idle, there is a light engine vibration which is a lot less since the air filters change and MAF cleaning with Electric Contact cleaner from HellFrauds (thanks Parrot of Doom: http://forums.mercedesclub.org.uk/showthread.php?t=18298). MPG has improved as well, and there is finally steam and water coming from the exhaust!

Water does come out of the exhaust this cold weather until it has warmed up


4. Finally, is there a Service Manual (I love those, bedtime reading!!) available? Other than the above, I'd like to check the sparkplugs as well (they were changed at 68 miles, car is now 93K miles) and anything else which is easy to check from the ignition and air side of things plus the oil and filter change - pretty good at following the manuals and like DIY as much as possible on my cars.

Only the Ebay thingd but hard to install and use

This is my first Merc (& German too), being a Honda Nut for some years I've usually worked on all my Hondas myself (engine rebuilt once too which took a few weeks :lol but with the Merc I don't know yet how often I'd need to go to an Indie or MB; guess that will become apparent with time. However, for starters if you can direct me to a guide on changing/checking/refurbing the alternator and the tensioner it would be much appreciated.

Thanks in advance for any help.

Arslan

Its taken some time for the tensioner to get noisy and a few more miles will not make any difference.
To isolate a noisy item,use a long wooden handled screw driver and put the blade on each item and the handle to your ear

 

[CL500Wizard]

Thanks very much for your input.

Malcolm, is there a a guide on to check the Idle Assembly and where is it located?

Thanks
A

 

[wireman]

My alternator went noisy it was found to be the front bearing (european std part 6303 2CS) my local auto electrician* replaced the bearing for £20 and I fitted a new brush/reg pack for a tenner. The alternators rear bearing is more reliable than the front, its just as well 'cos they take a wee bit more work to get at.

* G&S auto electrical Chorley Lancs, good guys who get to do all the auto electrical work on local police, fire and ambulance vehicles.

To do it your self just take off the unit and remove the pulley, if you can get that off the rest is easy, just remove the screws that hold the case halves together and it will split apart. Do make sure the pulley is tightened correctly on re-assembly.

 

[television]

I put the idler link in my first answer

If it is the alternator noisy (unusual) then here is the link to that

http://www.detali.ru/cat/oem_mb2.as...GA=722.633&CT=M&cat=07N&SID=15&SGR=030&SGN=02


The sure fire way to find what it is , is to slip off the serpentine belt, then just by rotating each item in the circuit by hand will give you the answer, and you will feel any roughness in the bearings

 

[CL500Wizard]

Sorry for being stupid, when you say "idler", you mean the tensioner? I misunderstood the idler assembly to be IACV (idle air control valve) related.

 

[television]

Sorry for being stupid, when you say "idler", you mean the tensioner? I misunderstood the idler assembly to be IACV (idle air control valve) related.

The idler is the little wheel that just takes up the tension

This is your arrangement

http://www.detali.ru/cat/oem_mb2.as...GA=722.633&CT=F&cat=65N&SID=21&SGR=220&SGN=01

 

[CL500Wizard]

Thanks very much, I'll check it all this evening and report back.

On the note of lights dimming and brightening, is this normal behaviour, as shouldnt it read 13.8v with engine running and 12.5v without?

 

[television]

Thanks very much, I'll check it all this evening and report back.

On the note of lights dimming and brightening, is this normal behaviour, as shouldnt it read 13.8v with engine running and 12.5v without?

Yes that it correct, those figures can be either way a little different, and that difference can be 10% of the total. So the lamps brightening when running applies to all cars

 

[CL500Wizard]

thanks for confirming that. after the pulley checks, it will be diagnosing the light engine vibrations at idle (which was cured a fair bit by cleaning the MAF and replacing filters).

 

[CL500Wizard]

Hi Malcolm ... this has just the one belt, not two as shown in the diagram.

 

[television]

That drawing is not so clear and you only have the 1 belt 10 in the link, you do not have the belt 20 on the 113 engine