ralftech

Hello everyone,

Can someone please help me figure out what’s wrong with the car? Took it to dealer and they have no clue.

Video Link:
Update: Dealer changed the coolant cap just today so hopefully the leaking stops. Any ideas about the noise?

Any help will be appreciated!

Trekt43

Same coolent problem here!! I couldn’t believe it when I saw your vid cause it’s an issue I’ve had since I got the car. I bought it used 12k miles, 2017 C43. They replaced the cap and did a bunch of tests, but it continues to happen. Dealer eventually said it wasn’t a problem. I don’t necessarily believe them but the car has plenty of warranty left so if it causes a problem down the line they’ll be fixing that too.

As far as the noise goes (the clicking right?) all c43’s click, it’s the fuel injectors, yours doesn’t necessarily sound excessive but thats over video. Please let me know if you find a solution to either of these!

TModelle

What’s your coolant level when cold?

AMGiggity

I hear a weird vibration coming on about 2-3 times per second; is that what you are talking about? what did the dealer say?

RichardCranium3

Same. Charles didn’t listen long or loud enough. Sounds like a low pitched goose honking. First thing my head went to us something rubber...loose belt maybe?

Mikey52

Wondering if anyone else has any info - I have the exact same issue as OP video with coolant splatter coming from the cap.

Trekt43

Coolant issue is “normal” in that it’s a know issue, doesn’t represent a danger, and isn’t caused by another defect. My service adviser finally found a tech notice about effecting our platform.

I basically said this sucks cause it causes coolant fumes to enter the cabin and they like sealed the lid shut some how and it hasn’t been an issue since.

of course, if this happens to you you should have them look at it as leaking violent could be caused by other problems

19’43s

It only happens when your parked for a long time and the fuel injectors make that weird noise every C43 has it I went to the dealership just to see what was up w my car cause it’s been doing that and they said since it’s directed injected you hear the loud fuel injectors dumping gas that’s all

stockbmw

What's that honking noise OP?? Sounds like you ran over a goose.

W205C43PFL

another forum member had that exact same issue but we were never provided an update on what it was
https://mbworld.org/forums/c450-c43-...ing-sound.html
MatthewJ suggested it had something to do with running low on coolant and topping off trapping air bubbles.. we are not sure what it is but since op had coolant leak this may be correlated

Spaggettio

I would ask dealer to complete full coolant flush, probably air in the system

ralftech

The dealer replaced the coolant cap twice so far. Issue hasn't appeared since.

W205C43PFL

OP, I am curious for an update... have the sound come back (I understand you mentioned it didn't appeared since but that was a few months ago)? If it did, from other threads and to their credit the fix is the pressure transducer. https://mbworld.org/forums/c450-c43-...ml#post8508372

I would be glad to hear If the coolant cap replacement actually fixed it fully though.

Thanks in advance.

MyNamesNotJimmy

Hi All - new to the forum but I have been looking for someone with the same issue when it comes to the weird honking noise...My car makes that noise - until today....I have a 2019 C43W4 and I started to hear the "Goose" sound (the honking noise) within the engine bay and inside the car. After a month at Mercedes-Benz of Beverly Hills they isolated the problem as being a bad vacuum valve for the twin turbos. Warranty should cover this wherever you are located. Hope this helps someone!! ~ Jimmy

W205C43PFL

Get the pressure transducer replaced: A0001531800

W205C43PFL

My bad, didn't read everything. In that case I am glad it solved it for you, not sure if we are talking about the same thing actually just with a different name but the pressure transducer was the culprit, is that the same thing you see on your work order?

MyNamesNotJimmy

It's still in the shop. The forman is taking it for another extended drive tonight to make sure that was the issue. When I pick it up tomorrow (crossing fingers) I will report what the work order details are.

MyNamesNotJimmy

Work Order Details: "Transducer internal diaphram is vibrating, causing the noise. Removed & replaced transducer, performed overnight test - no noise found after over-night test and tranducer swap."

@W205C43PFL - you were correct, sir!

W205C43PFL

Thank you for confirming and sharing the details on your work order, I am also glad they have it fixed for you as well. Please enjoy your car : )

ralftech

Hello, it fully fixed the problem. However, recently my vacuum pump in the back of engine was leaking. Swapped out a new o-ring and boost is back need to get a new check valve from Volvo now cause that's shredded too, and the pressure transducer is now probably messed up because of the garbage check valve Mercedes-Benz uses...

W205C43PFL

Glad you fixed the boost leak as well, good job

ShazV6

Was this repair covered under warranty? I have the same exact issue and I'm planning on visiting my mb dealer this weekend.

W205C43PFL

Yes warranty should cover it even if it isn't it is relative cheap and easy to replace yourself.

ShazV6

Good info, thanks. Maybe I attempt to fix myself.

W205C43PFL

Yup : ) but obviously if you have warranty you should utilize it if it is worth your time. To me, it isn't as I need to reschedule things and then wait there and worried about something else breaking when getting the car back (hopefully your experience is better). That said, my warranty has expired a long time ago I am just speaking from experience in the past.