aceman

Anyone ever heard of this...

When i turn the car off and get out, there is a low humming sound coming from somewhere in the engine compartment. If i open a door and close it - the noise stops...

anyone???

Aceman

vraa

It's normal, it's your brake hydraulic pump getting ready if I remember right. You have SBC, I have SBC. I put 2+2 together

MB Fanatic

Its all the electrical computers, SBC, and what not shutting down slowly. Our E55's do it, its just a characteristic of the E.

Nothing to worry about, trust me. I asked the dealer and he replicated it on his E class, and every other E class on the lot.

aceman

Ricky,

This is when i turn the car off....i haven't heard the car making noise in the garage a good few minutes after its off till this weekend...

i'll see how long it goes tomorrow. i end up opening/shutting a door to stop it.

aceman

vraa

At least your car stops making noises after a few minutes.

The bodies in my trunk keep thumping...

I think I've said too much...

HELL ONA HARLEY

Chances are that if you didn't open the door and shut it again it would have stopped on its own anyway.... Hell, If I don't hear buzzing, whirring, hissing, etc comming from my ride then I would swear something is going wrong with it.....

CE750

funny you should say that cause mine used to make a buzzing/pump like sound every time I opened the driver or pax door... and not it does it about every 10th time... I called the dealer asking if it was ok? Of course he had no idea

Firenza

You should be happy to hear this humming sound quite often. If not......haha....you are in trouble.

PCH_4.2

My car does the same thing too. But it goes away after about 5-10sec. I guess it's the SBC/computer related preparatory thingeeeeemajiggggg... I didn't even bother asking the dealer so that they can put their grease filled fingers allover my pristine ve-hic-le. Then, come back and tell me that everything checked out.

-=PCH=-

Bode

This noise is likely to come from the Sensotronic Brake Control System, in some occasions from the DC Airmatic, and is indeed absolutely normal (see details why below). As mentioned by some of you, without some light noises there is probably something wrong.....

The SBC system is functional as soon as it is “wakened” by:
• opening a door
• operating the central locking system
• depressing the brake pedal
• turning the key to position 1
• operating the parking brake

Activating SBC will:
• charge the accumulator (MOST LIKELY SOURCE OF NOISE !!)
• perform a Predrive Check
• move the pads towards the rotors with ~60 bar pressure
• erase the fault memory


The DC Airmatic wake-up occurs with any one of the following "inputs":
• key in the ignition
• open any doors
• open trunk lid
• activate parking brake
• pressing the brakes

Wake-up causes the DC Airmatic system to monitor vehicle ride height and adjust as needed dependent on vehicle load changes:
• if level is >30mm lower than normal (0mm +/-10) it will raise to normal level (if reservoir pressure >11 bar)
• if level is >65mm lower than normal, it will be raised even with a reservoir pressure of <11 bar by the compressor (prerequisite battery voltage >12.5v) to -63mm (critical level) (POSSIBLE SOURCE OF NOISE !!)
• if level is >10mm higher than normal, it will be lowered to normal

CE750

Very nice post... Sticky worthy.. you should post it as a stand alone thread.

aceman

I'm talking about after i turn the car off and get out. I realize it makes all kinds of crazy noises when i approach the car, unlock, and get in...

alewifebp

I think I've heard what you speak of. While most of the times I hear a hissing noise when I lock the car up, I sometimes do hear a humming style noise. I believe that it has to do with the Airmatic.

MB Fanatic

ITS NORMAL. My E55 and E350 DO IT ALL THE TIME. I know what you are talking, about. My dealer replicated the problem on nearly every other E on the lot and his own E.

FlintCDI

mine makes "noises" as well. It sometimes makes a "popping" sound and a chirp as if the locks were vacuum actuated like my 82 300d was. (Are they?)

MB Fanatic

Like I said earlier, its the SBC pump and other electronic computers shutting down after the car has been turned off or whenever. It is nothing to be scared about.

aceman

I'll keep an eye...rather an ear on it.

I have 7500 miles on it after 3.5 months and this is the first time i've heard the noise, thus why i thought there was (is) a problem.

thx for the info!

Aceman

HELL ONA HARLEY

So am I.......

CE750

I'm at 3.5 months too.. about 4500miles now.. and since it was new.. it's making new and different noises... I think it actually "adapts"

ruykava

haha, all absolutely normal, not to worry - it's a complex cars with lots of stuff doing their own thing. another source of noise on my E is the door mirrors folding when i lock up the doors - i don't understand why it makes this noise though - the S-class doesn't. then again, the S is a much quieter car in terms of locking sounds, brake sounds, etc etc - it seems Merc consciously wanted to remind customers of the technology, not sure if that's true. but i'll bet the "door lock" sound (mentioned above) is intentional, since the S makes absolutely no noise. nothing like a nice solid thump to give you a feeling of security.

iamsuperchris

Ya, I've never had a car that did, but everytime I park my car, I hear all sorts of hums, clicks, whatever, you name it. I've just gotten used to it. I read somewhere that these were "tests" the car performs on itself. I dunno. It still runs fine (except for my blasted top cylinders).

Scambo

Suspension adaptation is part of it - this happens as we exit and enter our cars. Also, braking components make this noise as they are updating signals from the car.

SPNJHockey

I've heard the "whirring" sound after shutting down. Assumed it was the electric radiator fan. (It is electric, no? )

SPNJHockey

My first problem:
After having the car for a couple of weeks, I returned to the dealer to get my license plates. I didn't want to wait for an employee to attach them, so I got them, and went home. As it turns out...I had to bend the plates vertically in the middle to get them to stay on the bumper (since the frt bumper is pointed). Looks a little cheesy too.

mdreef

SPNJHockey,
Go back to the dealer and ask for the front license plate bracket. It is designed to fit "nicely" on the front bumper and gives it a more finished look. My dealer gave it to me at no charge....