Erratic fan speed

Brucey

Member
Joined
Jan 7, 2010
Messages
24
Reaction score
0
Location
St Florent sur Auzonnet
Your Mercedes
E220 CDi W210 (2001) LHD
I have a 2001 E W210 with normal air-con. It seems that there's a problem with the fan speed control as the motor suddenly switches on to full for no apparent reason and fluctuates up & down. This doesn't however seem to be linked to wherever I set the fan speed. If it's in the horizontal position, it's erratic, if I turn it down a notch it just runs slow like it should. Is there a problem with the fan control knob or something more sinister?

and what steps do I need to do to remove/change the offending item.
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
I'm having the same problem.
I've changed the regulator but still the same.
The fan runs fine so not brushes.
What else can it be?
 

Frontstep

Senior Member
Joined
Apr 22, 2007
Messages
8,588
Reaction score
2,438
Your Mercedes
T210 320cdi
I would still be tempted to look at the bushes and take them out for both posts.
 
Last edited:

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Thank you Frontstep
I tried the fan with a booster pack and it ran well
I couldn't see an easy way to get to the brushes.
Does the fan pull off?

Cheers

Steve
 

Frontstep

Senior Member
Joined
Apr 22, 2007
Messages
8,588
Reaction score
2,438
Your Mercedes
T210 320cdi
The fan pulls out very easily, before that undo the under dash cover and try tapping the motor with something safe, sticking or worn out brushes will be revealed by speed changes.
If you have a rotary fan switch then contact cleaner spray can sometimes help.
The fan removes easily you need a good light and it should be obvious once your under there.
 

cleverdicky

Senior Member
Joined
Feb 25, 2009
Messages
2,385
Reaction score
2
Your Mercedes
MB
How do worn bushes cause the fan to run at full speed exactly?
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
I think Frontstep means erratic speeds.

I would still like to know how to get at them?

Getting the motor out was no real pain but I don't want to wreck anything opening it up
 

toby1

Senior Member
Joined
Mar 13, 2007
Messages
5,018
Reaction score
351
Location
West Berkshire
Your Mercedes
1998 CL420 C140
Mine sometimes behaves like this. If I turn the fan speed switch up/down a few times it seems to help. Not scientific though, granted.
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Could the problem be connected to the air intake?

I've noticed plenty of dead leaves that will need raking out
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Hi Frontstep
I'm unsure if the OP has had much joy.
I've no problem getting the motor out as I have done this and ran it on a battery to test.
I've also changed the regulator and still no joy.
I'm just about to vac the dead leaves out of the air intake as it could be a restriction causing overheating (maybe)
My question would be
How do you access the motor brushes?

Thanks

Steve
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Well managed to clear out a lot if debris from the water drains but couldn't get the cover off to access the air intake.
The fan runs properly up to speed 3 then it all goes haywire then stops.
Has anyone else had to solve a similar problem?
 

Biggles299

Senior Member
Joined
Nov 1, 2012
Messages
63
Reaction score
1
Location
Brighton
Your Mercedes
2014 CLS SB, 2008 CLS, 1999 C Class Estate, MINI MOKE
It's the brushes !
The connections are soldered on so you will need a soldering iron to change them, they are available from ebay for about a fiver.
That's the good bit........
Now for the downside, in order to preserve the £5 carbon brushes, MB use a nice soft material for the armature which wears at an equal or possible faster rate than the brushes.
If you are lucky you will be able to change the brushes once as still have a working fan.
At least that's my experience on a 10 year old C class with 180k on the clock.
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Thanks Biggles299
But how do you get to them?
I can't see how to remove the fan from the motor

Cheers

Steve
 

Biggles299

Senior Member
Joined
Nov 1, 2012
Messages
63
Reaction score
1
Location
Brighton
Your Mercedes
2014 CLS SB, 2008 CLS, 1999 C Class Estate, MINI MOKE
You don't have to separate the motor and the fan. The brushes are at the opposite end to the fan blades. Each has a braided wire soldered on.
There is a spring that holds the brush in place that you have to prise off.
I don't have any pictures unfortunately.
 

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Sorry
The brushes are defiantly at the fan end

What to do?
 

Attachments

  • image.jpg
    image.jpg
    476.5 KB · Views: 5

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
Well perseverance is the way forwards
The fan is a push (interference) fit onto the motor shaft.
Holding the motor spindle with a screwdriver I twisted the fan off.
This reveals two spring loaded brush holders with brushes worn down to the holder.
My next task is to locate some brushes ASAP as the old ones arnt worth saving.
Any suggestions of where I can get brushes on a Saturday afternoon would be appreciated

Steve
 

Attachments

  • image.jpg
    image.jpg
    474.8 KB · Views: 3
Last edited:

stevenN

Senior Member
Joined
Feb 3, 2011
Messages
484
Reaction score
0
Location
Nottingham, England
Your Mercedes
E220CDI W210 2002
I contacted an eBay seller who said I could collect anytime from Doncaster.
A really nice offer but for now I've packed the old ones out with a bit of foil and placed a order for some new brushes.
Changing them over looks a little fiddley but no less a faff as getting the motor our.
I know have a spare regulator
 

AIB understand your special Mercedes deserves a special insurance policy. We have a refreshing attitude to insuring high performance, modified, imported or classic and vintage cars and deal with the UK’s leading insurers. We offer discounts for length of ownership, where the vehicle is kept overnight and limiting the mileage and can also cater for those clients who need higher mileage and business use. To obtain a quotation please call the team on 02380 268351 or visit us atAIB Insurance
Top Bottom