vancity604

Has anyone notice a noise that occurs when you first drive the car in the morning? You have to have your music off to hear it.

The sound is a rattling in the engine.The sound occurs when I'm cruising and disappears when I gas or brake. Then the sound is gone after about 5 minutes of driving. It does not reappear for the rest of the day. It only reappears the next morning after it's been parked for the night.

Anyone know what I'm talking about?

angeloxnet

got a sound clip?

crxsnow

Yup, I hear this too. Car wasn't making that sound the first few months I had it. I hear it when I'm decelerating from 30 mph. Happens mostly in the morning. Will have to pay attention to the outside temperature to see if that has anything to do with it.

It's pretty loud, I can hear it from inside the car and when the windows are down. It's a very rapid clak-clak-clak-clak kind of sound. Kind of embarrassing it's making this type of noise.

I'll see if I can record the sound next time. Phones are not too good at picking up ambient sound.

vancity604

Tried recording noise today....then accidentally deleted it. Will record another clip tomorrow morning.

I park my car indoor and underground, so I don't think temperature has any effect on the sound. It just happens every morning.

digitallust_aus

Funnily enough, I had that sound yesterday in my Diesel.. sounded like something rattley and loose.
I did read a post where someone said it happened to them and it was dodgy water pump/starter motor? I can't recall which one they said.. will try and locate the post.

PeteInGilroy

I have a ticking type noise when the engine is cold and it goes away in 3 - 4 minutes. I think Glyn said it has something to do with the emissions.

vancity604

I recorded the sound:

https://www.youtube.com/watch?v=J1jb...ature=youtu.be

You hear me accelerating and cruising. The rattling noise happens when I'm not accelerating.

Is this the sound everyone else hears?

napickard

I have the same "clickity" sound the first thing in the morning and as others stated it goes away within a few minutes and only hear when windows down and no music.

amp512

I have the same sound on my C300 and goes away after few minutes of driving.

vancity604

Is the consensus that this sound is a normal thing or a problem that should be fixed?

ManiacGT

Rather than guess, perhaps speak with a dealer?

Pants-Flyer

I have a similar rattle,but I can only hear it when the engine is off!

My W205 is only a few weeks old and only covered 400miles.

But while playing in the garage the other night I found a funny rattle from the engine.

However its only there when the engine isn't running.

So from cold if I put the ignition in position 2 and leave it there the rattle will start.

I've attached the following video, which does seem to make it sound slightly worse than it really is.
For example its only just audible in the cabin, with the doors closed.

Once the engine is warm I can't hear it.

ManiacGT

Ooh that doesn't sound good.. Dealer time.

jolt8631

I agree - trip to the dealer.

Just for interest, does it do this on EVERY occasion, or is it, at all, intermittent? I presume, also, the noise stops directly that the engine is started?

It almost sounds like a relay chattering - almost like a starter solenoid suffering from a dodgy (high resistance) earth.

crxsnow

That's the sound. I don't remember hearing that when I first got the car and I've had it for seven months. Just started hearing it within the last month.

Pants-Flyer

The sound is present when the engine is cold.

So this morning got in the car, but the ignition to position 2 and the noise was there.
Turned engine on and I couldn't hear the noise.
Drove to a friends (less than 2mins) and turned engine off and back to ignition 2 and the noise was no longer present.

Tonight drove for 30mins, left the car on the drive for 3hrs. Turned the ignition to position 2 and the noise was there (albeit slightly reduced). Turned the engine on to back the car in the garage. Engine Off and back to Position 2 and the noise wasn't there.

All very strange.

jolt8631

Enough guessing - that trip to the dealer is, most definitely, in order.

NorthBayMB

Yep, I have the same exact issue with mine. Interested to hear what the dealer says. Please update if/when you get a chance. Thank you!

HiZh

It occurs when releasing gas pedal on cold startup.

jeamouse

I have the same sound, worse in the morning and I hear it all day. dealer found the steering wheel boot seal is broken which makes me can hear the sound clearly. After fix the the seal, sound is reduced but still there. They claim the sound is "by design" I am speechless

vancity604

Why would they design a sound like this? What benefit could that possibly provide?!

seanvree

yeah, I've noticed the same thing, sounds like a Diesel for the first couple of minutes. I just had my 10K servcie and they said everything looked fine, but I didn't tell them about it.

interested to see what they say.

rustycruiser

I heard the (deleted) video in this thread, and it is the "normal" cold engine ticking when coasting off the gas. Vic said it is the recirculating boost pressure, and is normal

https://mbworld.org/forums/c-class-w...nd-normal.html

e92miami

This is normal on all these new MB and BMW 4cyl high output motors they sound like diesels till it warms up. I heard it with all the cars at the dealers when testing both 328i and C300's. My car does it and you get over it when you are averaging 29mpg on a 3300lb car.

Jordyun

The link is dead so I can't listen to it... But I do have some noise similar similar to what you've described. This has been discussed other threads too (pasted one below). The dealer is saying it is the high pressure fuel pump and the sound is normal, while I'm obviously not happy about it... I'm considering filing a complaint with BBB...

https://mbworld.org/forums/c-class-w...ml#post6400224