Engine Rattle - W205 C220D

[Omz2020]

Hi Guys

I’ve noticed a small rattle in the engine bay which sounds exactly the same as this video...

Seems like others have got similar noise as a few videos online with same noise, doesn’t seem to cause any issues with the car but it’s annoying and can put off prospective buyers. Sounds like a loose screw rattling or something. Doesn’t happen all the time, but it does most of time, when in gear or when driving it happens.

Anybody have any experience with this?[/MEDIA]

 

[Rappey69]

Wow, no guesses? Must be a hard one.. All i can say it that it does not sound like an expensive noise !

 

[LostKiwi]

It's a diesel, they all rattle

 

[Omz2020]

I must say it is blooming annoying! Never recall the older MBs or BMWs making any odd diesel noises however.

I read somewhere that it could be the flaps of the turbo loose. Read another saying something about actuator.

Thought I’d check in with you pros on your thoughts

 

[Dean Fletcher]

At first I thought timing chain then I heard the noise . Can you tell which part of the engine it's coming from??

 

[Omz2020]

Thing is...it doesn’t seem to be coming from the engine, if you are stood in front of the car and looking down at the engine bay, it is on the left hand side of the engine bay.

Sounds like something around the gap between engine cover and Air flow sensor, but located further down in the bay) Can’t feel any rattle. Doesn’t go as far up as the air filter box or too far down towards the bumper nose. It seems like maybe a screw/tap/fast rattle. It’s not consistent, cold start it doesn’t, then when it’s warm it will come back intermittently.

There’s me thinking MB still make quality cars but seems like I’ve not been behind the wheel of one in a while so I must be mistaken!!

 

[steveq]

The water pump is in that vicinity as is the alternator.
You could try removing the serpentine belt and run the engine for a minute or two to see if the noise goes away.
If it does go away then it is one of the above or a pulley.

 

[Omz2020]

I think I’ve narrowed it down to around the turbo charger area. Under the MAF and under the air intake lays the turbo charger and noise is coming from there...but why the rattle??

 

[Uncle Benz]

Wastegate rattle? Or bypass flap?

 

[LostKiwi]

Put a screwdriver handle to your ear then put the other end on various parts where think the noise may be coming from. Might help pin point it more accurately.

 

[Omz2020]

Thanks for the suggestions

I have just come across this old thread from last year which had the EXACT same noise. OP had it diagnosed as below but then disappears and doesn’t say how he got it fixed/if at all ...

Turbo actuator just before the engine pulls vacuum on startup.

The actuator linkages rattle for a few seconds then it goes away.

https://forums.mercedesclub.org.uk/index.php?threads/turbo-rattle-om651-w212.175522/

 

[Rappey69]

Could you let it get its rattle on, remove the serpentine belt then see if the rattle is still there.. If nothing else it will eliminate anything that the belt goes around?
Sounds like a loose nut and bolt rattling in a hole.

 

[Roxie]

Polly belt tensioner rattle.
It could be the turbocharger change over valve but much more likely to be the tensioner.

 

[Omz2020]

Could you let it get its rattle on, remove the serpentine belt then see if the rattle is still there.. If nothing else it will eliminate anything that the belt goes around?
Sounds like a loose nut and bolt rattling in a hole.

Is there An easy way to remove the belt, or is it similar to this

also usually belt would squeal so wondering which part of belt could produce this noise...

I’ll be a mechanic by end of this..

 

[Roxie]

If the belt is also squealing then I suggest replacing the belt along with the tensioner and whilst it is off checking the rest of the pulleys for correct alignment and bearing wear.
Whilst the engine is idling look at the belt it should remain central on the pulleys.

 

[Omz2020]

If the belt is also squealing then I suggest replacing the belt along with the tensioner and whilst it is off checking the rest of the pulleys for correct alignment and bearing wear.
Whilst the engine is idling look at the belt it should remain central on the pulleys.

Sorry the belt isn’t making any noise whatsoever. Just that rattle noise

 

[sheryllee]

Hi Guys

I’ve noticed a small rattle in the engine bay which sounds exactly the same as this video...

Seems like others have got similar noise as a few videos online with same noise, doesn’t seem to cause any issues with the car but it’s annoying and can put off prospective buyers. Sounds like a loose screw rattling or something. Doesn’t happen all the time, but it does most of time, when in gear or when driving it happens.

Anybody have any experience with this?[/MEDIA]

Maybe due to air/fuel mixture in the engine cylinder being ignited by the heat of compression as the piston is moving up on the compression stroke and that's why you hear the pinging and rattling noises.

 

[D5meister]

The turbo control arms can rattle on these. I removed my aircleaner to watch this rattle after running with serp belt off did nothing to change sound. You can jiggle/shake the arm, along its length.
The sound goes away with a decent rev as the actuator arm moves and it loads it and stops rattling. You could add a weak spring gently pulling on the arm to null the rattle.
I dont listen to my engine anymore. Ive kind of made peace with it. They are noisey. They work ok though. Not sure if renault or whoever. My waterpump bearing has a fair bit of slack, poor at 58k miles. Changed volvo one at 200k miles as a maintenace precaution.
A workmate said last week yup it sounds like a bag of nails..
My volvo s60 D5 2.4l diesel turbo has covered 260k miles and is quiter.