Sound after car is parked and off
Thread Starter
Senior Member
Joined: Jan 2018
Posts: 254
Likes: 16
2014 C300 4matic sport sedan
Sound after car is parked and off
anybody know whAt the sound is after you park and turn off the car and like a minute or two later something is making a sound. I dont know how to describe it but it sounds like its coming from front of car.
Junior Member
Joined: Oct 2006
Posts: 15
Likes: 1
I have a 2014 C350 and it intermittently gives off a sound like that in the You Tube clips below - with engine off, sometimes for several hours
2008 ML 350
2015 ML 350
Took it to the dealer, and the shop foreman said it's normal, don't worry about it, but didn't quite explain the source of the sound!
Anyone can advise please?
2008 ML 350
2015 ML 350
Took it to the dealer, and the shop foreman said it's normal, don't worry about it, but didn't quite explain the source of the sound!
Anyone can advise please?
Member
Joined: Mar 2017
Posts: 144
Likes: 8
From: Vancouver, BC
2014 Mercedes C350 Coupe
Not too sure, but there's quite a lot of systems in these cars. My car also makes a sound after shutting off completely, but it doesn't sound as high pitched as in the video. My sound is due to the throttle body opening and closing to let out pressure buildup after engine shutdown. You can also hear relays going on and off after shutdown too. My mom has a 2014 E350 cabriolet, and her car makes hissing sounds due to the air suspension resetting. I wouldn't worry about it unless error codes actually show up when you scan the car.
Junior Member
Joined: Oct 2006
Posts: 15
Likes: 1
Laxpower87, sorry if I am hijacking your thread. 
Just to add to the You Tube clips I pasted above, the noise appears at
1st clip (2008 ML350): 13-16s, 40-43s
2nd clip (2015 ML350): 1-2s, 11-12s, 21-22s, 32-33s
I realize the clips are from MLs (different years), vs my car which is 2014 C350, however the noise sounds similar and these are the only clips I can find on You Tube.
The noise comes on my car under the hood, with engine off and key removed (actually key is far away from the car which has KEYLESS GO).
This goes on several hours after the last shut-off ... noise for a second or two, silence for a while (10-30 seconds), then the noise, ... repeat ...
Does not sound like a fan coming on at all, but some sort of metal / valve / relay / grinding noise as in the clips.
Just baffled what it is ... if anyone knows please share! Thank you.
Just to add to the You Tube clips I pasted above, the noise appears at
1st clip (2008 ML350): 13-16s, 40-43s
2nd clip (2015 ML350): 1-2s, 11-12s, 21-22s, 32-33s
I realize the clips are from MLs (different years), vs my car which is 2014 C350, however the noise sounds similar and these are the only clips I can find on You Tube.
The noise comes on my car under the hood, with engine off and key removed (actually key is far away from the car which has KEYLESS GO).
This goes on several hours after the last shut-off ... noise for a second or two, silence for a while (10-30 seconds), then the noise, ... repeat ...
Does not sound like a fan coming on at all, but some sort of metal / valve / relay / grinding noise as in the clips.
Just baffled what it is ... if anyone knows please share! Thank you.
Last edited by impala; Apr 25, 2018 at 01:18 AM.
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
Hi,
On the W204,
It is the recirculation flap closing then re opening, I seen it one time I had the main duct out under the hood while changing the battery.
Not sure why it happens may be they program it in so all the heater flaps have a cycle so they don't seize up.
On the W204,
It is the recirculation flap closing then re opening, I seen it one time I had the main duct out under the hood while changing the battery.
Not sure why it happens may be they program it in so all the heater flaps have a cycle so they don't seize up.
Last edited by NZ-Merc; Apr 25, 2018 at 04:45 AM.
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Junior Member
Joined: Oct 2006
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Likes: 1
Thanks NZ-Merc. I Googled along the lines of "Mercedes W204 heater recirculation flap making noise" and couldn't find much information or sample clips.
I am not sure if I understand the logic of repeatedly closing/opening the flap so frequently - it cycles multiple times per minute, for hours after engine off (I can hear it while washing my car). Wouldn't once a day suffice to ensure the flaps don't seize, say run a cycle right after engine off?
I am not sure if I understand the logic of repeatedly closing/opening the flap so frequently - it cycles multiple times per minute, for hours after engine off (I can hear it while washing my car). Wouldn't once a day suffice to ensure the flaps don't seize, say run a cycle right after engine off?
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