Loud Noise when the car is off
Thread Starter
Junior Member
Joined: May 2018
Posts: 15
Likes: 2
2017 C300 Coupe
Loud Noise when the car is off
So i have a 2017 C300 coupe. This problem has been going on since last year june, which is when i got the car.
There is a noise coming out of the engine bay whenever the car sits parked outside on a hot day.
I live in a building so i park indoors, however this sound happens after driving 15-30 mins (normal driving, not aggressive) and then parking the car for at least 30 mins to an hour.
Here's a two links to 2 videos of the issue:
1) https://youtu.be/1k76yzVUNF8
2) https://youtu.be/p3otM_EzEPE
I've spoken to my local dealer. What they said is that theres an electrical coolant pump that runs when the car is on. Also, theres an auxiliary pump that runs when the car is off. For the past year they have been telling me its normal. However, i went 2 weeks ago and FINALLY had them acknowledge that it is NOT normal. I have an appointment on May 28th.
Anyone has this issue or knows what it could be caused by?
There is a noise coming out of the engine bay whenever the car sits parked outside on a hot day.
I live in a building so i park indoors, however this sound happens after driving 15-30 mins (normal driving, not aggressive) and then parking the car for at least 30 mins to an hour.
Here's a two links to 2 videos of the issue:
1) https://youtu.be/1k76yzVUNF8
2) https://youtu.be/p3otM_EzEPE
I've spoken to my local dealer. What they said is that theres an electrical coolant pump that runs when the car is on. Also, theres an auxiliary pump that runs when the car is off. For the past year they have been telling me its normal. However, i went 2 weeks ago and FINALLY had them acknowledge that it is NOT normal. I have an appointment on May 28th.
Anyone has this issue or knows what it could be caused by?
Thread Starter
Junior Member
Joined: May 2018
Posts: 15
Likes: 2
2017 C300 Coupe
Can you take a video and post it whenever the issue occurs? I want to compare how it is. The reason being there should be a very low noise when you turn off the car which is the pump/valve closing. That is completely normal, which is not what I’m getting lol!
Thread Starter
Junior Member
Joined: May 2018
Posts: 15
Likes: 2
2017 C300 Coupe
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
Because that's normally what happens, the car sits hot, the light control units get hot, and cooling fans in them can run for an hour afterwards if needed. They generally create a high pitched sound that people notice, and it's so long after the car has been shut down, people tend to notice. There are bulletins saying that it's normal, as long as that's where the noise is coming from.
Junior Member
Joined: Apr 2017
Posts: 57
Likes: 3
C300
The rough shift from 1-3 stealership told me oh that’s normal. They designed it that way. Really?
Now this whistling bullcrap is normal again. Really? This is my first owned MB but we had Mb’s growing up and none of this rough shift **** happened and now whistling engine crap. Krauts needs to do some fixing. I hope this is not my last MB. My bro told me to get a Bimmer I should’ve listened.
Now this whistling bullcrap is normal again. Really? This is my first owned MB but we had Mb’s growing up and none of this rough shift **** happened and now whistling engine crap. Krauts needs to do some fixing. I hope this is not my last MB. My bro told me to get a Bimmer I should’ve listened.
Last edited by applehaus01; May 30, 2018 at 12:58 AM.
Trending Topics
Thread Starter
Junior Member
Joined: May 2018
Posts: 15
Likes: 2
2017 C300 Coupe
The rough shift from 1-3 stealership told me oh that’s normal. They designed it that way. Really?
Now this whistling bullcrap is normal again. Really? This is my first owned MB but we had Mb’s growing up and none of this rough shift **** happened and now whistling engine crap. Krauts needs to do some fixing. I hope this is not my last MB. My bro told me to get a Bimmer I should’ve listened.
Now this whistling bullcrap is normal again. Really? This is my first owned MB but we had Mb’s growing up and none of this rough shift **** happened and now whistling engine crap. Krauts needs to do some fixing. I hope this is not my last MB. My bro told me to get a Bimmer I should’ve listened.
As per your reply, Mercedes is great quality, unfortunately no manufacturer can guarantee that there will no issues. There are always outliers and I happen to be one. I would always choose Mercedes over BMW.
Last edited by mhabashy16; Jul 12, 2018 at 07:01 PM.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Newbie
Joined: Nov 2018
Posts: 4
Likes: 0
c300 sedan 2017
So the dealership called me today, they said they have potentially found the culprit. There’s a collapsed hose that equalizes the AC pressure system. They’re going to replace the whole unit tomorrow. I’m gonna to pick it up and hopefully no more noise.
As per your reply, Mercedes is great quality, unfortunately no manufacturer can guarantee that there will no issues. There are always outliers and I happen to be one. I would always choose Mercedes over BMW.
Thread Starter
Junior Member
Joined: May 2018
Posts: 15
Likes: 2
2017 C300 Coupe
Hey Ron! Yes my dealer has resolved the issue and charged all the work on the warranty. They diagnosed it as a collapsed hose in the AC unit which equalizes the pressure. Due to the hose being collapsed, you have that noise.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Newbie
Joined: Nov 2018
Posts: 4
Likes: 0
c300 sedan 2017
Hey Ron! Yes my dealer has resolved the issue and charged all the work on the warranty. They diagnosed it as a collapsed hose in the AC unit which equalizes the pressure. Due to the hose being collapsed, you have that noise.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Thank you very much. I really appreciate you taking the time in helping me with this information.
Newbie
Joined: Nov 2018
Posts: 4
Likes: 0
c300 sedan 2017
Thanks again Mohamed. I am in Scottsdale Arizona, so I will have my dealer contact Silver Star in Montreal. I will let you know what they find. Your video is almost exactly the same as the video I took of our car and showed my dealer. I really appreciate your help. Ron
Newbie
Joined: Nov 2018
Posts: 4
Likes: 0
c300 sedan 2017
Thanks Joe, but I don't think this is the same thing. In my case I just backed the car (when cold) out of the garage and 20 minutes later the sound started. It doesn't seem to be related to engine temp. It can happen when engine is hot or cold. It's more of a whistle like a pressure leak may sound like. I don't think it's a motor or led light cool down sound. My dealer thought it was the AC balance valve. He replaced it but I don't think he replaced the hoses. So I think what Mohamed's dealer did could be the answer. Thanks very much Joe for checking.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,012
From: Miami, FL
2003 CL 600
Thanks Joe, but I don't think this is the same thing. In my case I just backed the car (when cold) out of the garage and 20 minutes later the sound started. It doesn't seem to be related to engine temp. It can happen when engine is hot or cold. It's more of a whistle like a pressure leak may sound like. I don't think it's a motor or led light cool down sound. My dealer thought it was the AC balance valve. He replaced it but I don't think he replaced the hoses. So I think what Mohamed's dealer did could be the answer. Thanks very much Joe for checking.
Member
Joined: Oct 2016
Posts: 110
Likes: 14
M3
Hey Ron! Yes my dealer has resolved the issue and charged all the work on the warranty. They diagnosed it as a collapsed hose in the AC unit which equalizes the pressure. Due to the hose being collapsed, you have that noise.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Since they replaced the unit, it rarely happens. If it does happen, it’s very very quiete and goes away fairly quick.
My dealer is called Silvwe Star Mercedes Benz. If you speak to them, ask to speak with a person called George. He’s th foreman that diagnoses all the issues. Tell him Mohamed sent you, he will know me from all the times I went back to them 😂.
i hope your issue gets sorted out.
Member
Joined: Oct 2016
Posts: 110
Likes: 14
M3
