Engine sounds like a diesel
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 19
Likes: 1
GLC300
Engine sounds like a diesel
The 4 cyl turbo engine on my 2018 GLC300 SUV is louder than what I consider normal and sounds like a diesel. It sounded like the like the valves were tapping. Is this normal? I bought it with 27K miles and now has 30K miles.
I suspect a MB should be somewhat quiet considering it is supposed to be luxury class.
I suspect a MB should be somewhat quiet considering it is supposed to be luxury class.
Member
Joined: Feb 2017
Posts: 196
Likes: 28
From: Oregon, USA
BMW X3, Mercedes GLC300 (EDP)
This was discussed on this forum a couple of years ago. I don't remember much about the discussion except the loud valve noise is normal. Here's the link:
https://mbworld.org/forums/glc-class...ds-diesel.html
https://mbworld.org/forums/glc-class...ds-diesel.html
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 19
Likes: 1
GLC300
Engine sounds like a diesel
Thanks for all the replies. I'm surprised the diesel sound is "normal" for a MB. and their engineers haven't figured out how to quiet it. i guess I'll have to live with it.
Thanks again!!
Thanks again!!
Senior Member
Joined: Apr 2017
Posts: 259
Likes: 44
From: Denver, Colorado
2018 GLC300 4matic SUV
This was discussed on this forum a couple of years ago. I don't remember much about the discussion except the loud valve noise is normal. Here's the link:
https://mbworld.org/forums/glc-class...ds-diesel.html
https://mbworld.org/forums/glc-class...ds-diesel.html
The injector noise is noticeably louder upon cold starting because the injectors use a rich setting on cold starts. This setting produces the hotter exhaust gasses that are necessary to quickly heat up the catalytic converters and get them working, thereby reducing emissions. If you start the car in an enclosed space and then allow it to idle for several minutes, you will at some point hear a noticeable reduction in the noise level. This occurs when the cats have reached operating temperature and the computer dials the fuel injection level back, making them quieter. This too is something you'll notice in most DI cars.
Last edited by mtberman; Jul 17, 2019 at 02:12 PM.
Thread Starter
Junior Member
Joined: Nov 2018
Posts: 19
Likes: 1
GLC300
Thanks for the reply. I now understand how it happens. The sound was high even after driving for 20 miles. So, having a warm engine still produced noise. You mentioned soundproofing. I wonder if it needs more or whatever was there is no longer? It looks like a trip to the dealer in in the cards.
I also have a problem opening the cargo door from the inside. I read the manual and followed directions but it only works be opening from the outside. Any ideas or should I start another thread?
I also have a problem opening the cargo door from the inside. I read the manual and followed directions but it only works be opening from the outside. Any ideas or should I start another thread?
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Member
Joined: Feb 2017
Posts: 196
Likes: 28
From: Oregon, USA
BMW X3, Mercedes GLC300 (EDP)
You should start another thread about the cargo door. A new thread will attract readers interested in the question.
But, out of curiosity, why/when do you need to open the cargo door from the inside
? I assume you are talking about the rear hatch door.
But, out of curiosity, why/when do you need to open the cargo door from the inside
? I assume you are talking about the rear hatch door.
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GLC 300d 4matic
It takes a slight press and hold to get it to function.
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GLC 300
Just to be clear, the noise in question is not "valve noise". The engine is a direct-injection design and the tapping noise is the high pressure fuel injectors working, as stated above. They operate at crazy high pressures and make a noticeable tap tap tap noise. All direct injection engines do this to some degree. The amount you actually notice or hear depends on how effective the sound deadening is.
The injector noise is noticeably louder upon cold starting because the injectors use a rich setting on cold starts. This setting produces the hotter exhaust gasses that are necessary to quickly heat up the catalytic converters and get them working, thereby reducing emissions. If you start the car in an enclosed space and then allow it to idle for several minutes, you will at some point hear a noticeable reduction in the noise level. This occurs when the cats have reached operating temperature and the computer dials the fuel injection level back, making them quieter. This too is something you'll notice in most DI cars.
The injector noise is noticeably louder upon cold starting because the injectors use a rich setting on cold starts. This setting produces the hotter exhaust gasses that are necessary to quickly heat up the catalytic converters and get them working, thereby reducing emissions. If you start the car in an enclosed space and then allow it to idle for several minutes, you will at some point hear a noticeable reduction in the noise level. This occurs when the cats have reached operating temperature and the computer dials the fuel injection level back, making them quieter. This too is something you'll notice in most DI cars.
