Loud BANG coming from my S550 5 seconds after startup
Thread Starter
Banned
Joined: Jun 2006
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From: NYC
2014 S550
Loud BANG coming from my S550 5 seconds after startup
and a second time
Happens Every time it starts, with at least 30 minute rest period.
Can you tell me what this is? My Service Adviser is having his foreman listen to it as well.
Will bring the car in for service.
Thread Starter
Banned
Joined: Jun 2006
Posts: 3,640
Likes: 13
From: NYC
2014 S550
MBWorld Fanatic!
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From: Sydney, Australia
W203 slightly modified
On second thought I will go for broken stepper motor mount on the heater box. Once a stepper motor goes funny the AC controller keeps trying to confirm if it works normally. In fact it tries all the stepper motors on startup but it tries the broken one twice.
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Thread Starter
Banned
Joined: Jun 2006
Posts: 3,640
Likes: 13
From: NYC
2014 S550
Thanks! Have a Service Appointment this Thursday, will bring your message to the dealership. I really appreciate it. Never heard this before in all the years of owning this car.
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MB’s of all kinds.
It literally sounds like someone is slapping the side of your car door or something. That is very very odd. It does not sound like an engine issue/backfire because this thump or bang seems too calm and quite. Are there any warning lights? They sounded different in the videos due to having the hood open. I am tempted to call my indi shop tomorrow just to see if I can get an answer for you. I personally have never herd of this on a Mercedes before and I have been around them my whole life.
Last edited by C280 Sport; Oct 7, 2012 at 11:36 AM.
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CLK55 W209, CL63 W216
My CL is making the same noise randomly and very infrequently. It's not engine related as I've had it happen in my garage with the ACC on but the engine off. It's coming from the rear of the car somewhere. Anyone have any ideas?
Newbie
Joined: Aug 2019
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mercedes 2008 cl65
Same here on my 08 cl65
I think it’s a pump issue. You might be low on fluid. I added some green fluid for ABC and sound is gone now. Might be an air bubble in the line.
Super Member
Joined: Oct 2011
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From: Illinois
S560/SL550/LS460/Q70L 5.6 AWD
It is from the ABC system, as Stavros mentioned, you may be low on fluid, you can add but eventually will do the same, check the system (including the struts) you may have a leak somewhere, on my car it was one of the rear struts leaking ( at very low mileage ). Took the car to the Mercedes dealer but they did not know why, however I was told that one of the struts was leaking, so I realized the the system had air inside, new strut, everything back to normal
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From: Washington, DC
2007 S600, 2007 Chrysler 300 SRT8, 2000 C5 Corvette, 2017 Mustang GT, 2023 300C, and a 2019 Lincoln
Yup, mine did it too (2007 S600 with ABC). Added a little green Pentocin fluid and it went away.
Do regular maintenance on your ABC system including filter and fluid changes every 20K miles, and you will be fine..
Do regular maintenance on your ABC system including filter and fluid changes every 20K miles, and you will be fine..
