Ferris_E550

Hello everyone,

I parked my car this afternoon after a short trip. Came back to pick up my phone -forgot it inside the car- and I heard this strange noise coming from under the hood. Please have a listen.

So the car being parked in the garage, no keys and alarm is off.

Would appreciate any thoughts of what could that be.

Thank you all

dbldpr

Usually noise is the fan still cooling off the car, I have no idea what your noise is sorry

thefisch

Having trouble hearing the fan from the file you posted. Have you identified the location of the sound.

Possible locations from past fan noise threads that I recall include:
1. radiator fan - front of car
2. HVAC fan (in 'drying' mode) - inside plastic cowl near bottom of windshield passenger side
3. LED headlamp cooling fans - only on applicable models with these lights.

Ferris_E550

Thank you for the info

It was hard to identify the location of the noise. However, I don't believe it is a fan noise as it was not constant. Since you mentioned the possible three locations I will look these locations over and check if the noise coming from one of them.

KEY08

That is a strange metal sound that I have never heard before. Sounds like a woodpecker trapped inside the engine compartment drilling on a metal pipe. Bizarre
These E class cars are noisy, but that is a first for me.

hamooda_47

they are noisy even when in P or N, but this is as KEY08 said, very strange.

Never heard it before. Keep us update..

Arrie

Really strange noise and the two intervals between the three noises are very much the same 15-16 seconds...


Does this continue for long time after you turn off the car? if it stops and the interval gets bigger between the sounds before it stops then could it be cause by the engine coolant pressurizing and pushing thru the pressure valve at the radiator cap?


When the engine stops the coolant stops circulating and heats up inside the engine channels to a point it can start boiling. This would cause excessive pressure in the system and perhaps cause steam to escape thru the pressure valve to the ganister.


The Audi Q7 I had was equipped with an electric circulation pump that kept running and circulating the engine coolant after engine shut-off until the temperature was below some point that does not make the system overly pressurize. Wish my MB had that too...

mleskovar

It does sound like some fluid or gas pressure being released into a chamber. Do you have Airmatic?

Arrie

Yes, I have airmatic but the sounds it makes are clearly air blowing out. Nothing like in your film clip.

mleskovar

I was wondering if the OP has Airmatic.......

Arrie

Sorry, I thought your post was from the OP...

KEY08

I have had two Airmatic MB's and have never heard a sound like that, but that sound does have a "sucking through a straw" kind of tone to it. You may be on to something.

Ferris_E550

Arrie. The noise did really sound like what you descried "steam to escape thru the pressure valve". Yes the interval was getting bigger -i waited in the garage for around 15 minutes and at some point i though it was happening with over a minute interval- I checked the car few hours later and it was quiet.

Yes the car has Airmatic

I did not drive the car the past two days, but will keep you all posted.

Thank you all for your replies

MPTLPTR

Any updates from the OP?

I have a 2014 E350 (so it is not related to airmatic) and noticed the same exact sound coming from somewhere in the engine bay when the car is off after a drive. It only happens after some drives. I don't think it has happened since the car was new. Somewhat periodic in nature. Sometimes it stops after a few minutes, sometimes it will take an hour or more to stop.

Ferris_E550

I really have no updates and I kinda forgot about that noise. But, it is exactly as you described it (Somewhat periodic in nature) and it does not happen after each drive, it is really intermittent.

MPTLPTR

Ok, thanks. It doesn't seem too concerning so I will probably just bring it up next time I go to the dealer. Will report back if they find anything.

Lolxa

Hey, I drive a 2010 E550 with airmatic. I just heard this sound from my car too. It comes from the lower half of the engine. It was my first time hearing this sound since I got the car in February. It seems to come on 15- 30 minutes after switching the car off. A few hours later i checked up on the car and the sound was gone. Just wondering if anyone has an update of what is going on?

SEC1939

do you have the lighting pkg? These have a cooling fan that runs for a bit after you turn off the car. Mostly in warm weather

Lolxa

Im not sure if i did. I have the hockey stick DRL, with the Xenon beams up front? But the weather outside is like -20c I didn't hear it in the summer?