Martin78

Excuse me but i have c215 cl600 just for 3 weeks

but i wonder
what gives such audible sound after ignition on
its like some kind of ventilator

It comes from passenger side, near (under) headlamp
is it normal?

I think i hear it everytime, even engine is running

graytalon2000

There is an air pump that comes during cold start. It helps to heat up the cats quicker. This is normal.

Martin78

I thought so. Thanks for answer

The only problem is that this pump wont stop after minute or two
sometimes it sounds like hairdryer even when engine is hot.
I hear it almost everytime.



I know about well known issue with relay and air pump
so i bought cheap china replacement for less than $200
and i'm waiting for it


but please tell me, Does it start after ignition on, even when engine is hot?

graytalon2000

No, it should only run when the engine is cold and only for a short time. Mine runs for maybe a minute or so.

Martin78

thank you very much!

my pump starts every time after ignition on, and gives engine check very often
so it needs to be replaced for sure

tusabes

Anyway back to the main topic of this thread , the fan coming on high is a classic symptom of a bad SAM or ecu due to water damage so you must fix the water damaged parts before replacing the SAM or ecu unless you want to immediately fry the new one you put in.

tusabes

If you haven't already checked the reservoir under your windshield for standing water , check it now


There's a drain at the bottom that gets clogged you can use a long tool to poke it open

Martin78

I removed air pump realay. Nothing changed. Then i plug new original relay. Still hear this fan sound. Air pump dont vibrate when i'm touching it. Sound comes not from this pump but from under the headlamp all the time after ignition on. Computer gives no errors.

Martin78

My mechanic can't help also,
he don't know what cause this hum after ignition on
but definitely this is not an air pump

he claims that this is abc cooling system and something is wrong with that, but he don't know what (no errors)
but after some research i don't see any special ABC fan in my car

I know that common issue with abc is pulsation dampener failure
which gives hum sound from passenger side, but the main question is

Is it possible that abc pulsation dampener gives fan type sound even when engine is off?
when i just turn ignition on?

(i don't have any visible abc issues)


update: after more research i probably found the reason
my auto is equipped with webasto heater
and it has own fan which i hear
its located under the right lamp, near bumber

bingo


but i must find out why its running even when engine is hot
and how can i turn it off
maybe one of temperature sensors is faulty

Martin78

Hello one more time

This was not webasto noise, webasto is running quieter

i recorded short clip with this strange issue


maybe someone can give me any suggestion?

tusabes

Isn't that the electric fan ?

Martin78

no, its not main radiator fan

but i found something like this

http://www.mbpartsworld.com/showAsse...rimLevel=20530

additional radiator and additional fan blower
650, 670
on the right side...

i'm confused
anyone can tell me, what is purpose of this additional fan blower in my car???
and what is the reason it's running all the time?

tusabes

That noise is a fan. It's not an air pump or webasto heater . If you say it's not the main fan then it's the aux fan, and as I said several posts up, when a fan comes on high speed and will not shut off it is usually due to damaged ecu

Martin78

This part is additional fan ecu?
http://www.aliexpress.com/item/02754...418246892.html

Martin78

small update

on cl600 m137 there is no additional fan ecu!
i bought this part, but my mechanic told me that only amg cl55 or cl500 have additional ecu module

I had faulty temperature switch, very cheap
relay was good, fan was good

biker349

thanks for update.