Hello to all,

I recently purchased a 2015 C300 certified preowned with 8700 miles about 4-5 weeks ago. I have driven the car for about 1500 miles. I started hearing a rattling noise from the engine about 2-3 weeks ago. The noise is not very discernible, and is only heard if you really try and listen for it. I noticed I heard the noise mainly in city driving, and it comes every time I step on the gas and let go of the gas. It is also worse when there is a cold start to the car. Another problem I had was the touchpad was not working at all.

I took the car to the dealership to have it checked. They kept the car overnight to diagnose the problem, and I got a call the next morning from the Manager stating the car engine will have to be opened and new parts will have to be replaced to fix the problem. I am not sure exactly what the problem is, but the manager was explaining the noise may be coming from the pistons, or crankshaft. He also told me they will fix the touchpad, and the issue with the touchpad is a known issue. I am not worried about the touchpad. The manager said fixing the rattling noise is a big job and could take up to 7-10 days.

I am just concerned about the car now. I have only driven the car for about 1500 miles and I am already having problems with the engine. Will the car ever be the same after they open up the engine? Also they gave me a loaner car, and the loaner seems much better to drive. The loaner is a 2015 C300 also. The suspension and steering on the loaner car seems a lot firmer and sporty than my car, which is what I wanted. My car feels soft. The only difference between my car and loaner is that my car is 4 matic, and the loaner is a RWD. Did I get a lemon car? This is a certified MB car. Shouldn't the engine rattling issue been caught when the car was Certified?

I would appreciate any advise

 

Any car can have an issue. But MB will stand behind the car and my recommendation is to let them fix it and then see how it feels to you. As to whether they should have caught the issue when they went through the prep process? Not necessarily. It might have just started happening since you took delivery. I wouldn't worry about them opening the engine and replacing parts.

 

I have the same problem, heard rattling on my engine, took it to the dealership and they said there is something wrong with the piston wrists. The part is coming from Germany so it's going to take a couple of weeks. My 2015 C300 4matic is 4 months old with 2300 miles. Have a problem with the driver's side window as well, one of the pins for drip rail was unsecured, they've put it back and it somewhat improve but still hearing it.

 

mine sounds like that, but its the direct injectors

 

No unusual noise in mine (c200 petrol(c300 engine)). There is a rattle for a minute at the start that sounds a bit like a heat shield but that goes away.

 

Any update to this? Mine is also experiencing this. In the morning step on gas and let go(coasting) I hear a sound along the lines of clak-clak-clak-clak. Goes away when the car warms up

 

So the dealer did finally fix my car. I took about 2.5 weeks. The technician at the dealer told me that there was an issue with Pistons wrist pins not being the correct tension specifications. I thought I heard the noise more with a cold start too. He said that probably happened because as the engine warmed up the wrist pins would expand and it would be correct tension not causing the noise. The tech said he read something in the MB bulletin they receive about this being a problem, and the wrist pins would have to be replaced.

I got my car back, and I checked for the noise. I thought I was still hearing the rattling, but the tech said that noise was from the fuel injector, and there was no rattling. So I took the car home, but I am still a little skeptical. They opened the whole engine and replaced almost half of it, so I am not sure if there will be problems in the future. The car runs good though without any issues so far.

If you keep hearing the noise, take it to the dealer. Hopefully they can diagnose it. My dealer kept the car overnight and did a cold start the next day. The manager then acknowledged there was a engine rattling issue. They should know about this, since the tech told this was in the MB bulletin.

Let me know if can be of any help.

 

Thanks for the reply. I'll get it checked out in a couple of days.

 

I took my C300 4MATIC to the dealer today for five(!) small items, plus not satisfied with the way Steering Assist does not really follow the lanes or the car ahead. (A list will follow this more important discussion.)

When I got home, i got a call from one of the service coordinators telling that when the mechanic drove the car to listen for the wind noise above the driver's window, he also the heard a ticking sound that I had been hearing for the last month. However, I had heard it only upon a cold start. I would hear it briefly while cruising or accelerating, but would go away when I was off the throttle. Then it seemed to go away. The mechanic heard it when the car was well warmed up. My C300 was delivered in the first week of 02/15, and it has 5,000 miles.

The service coordinator said they will replace the connecting rods (!) and estimated it will take two weeks. They will get the parts within 24 hours, and I assume they will start tearing down the engine engine without waiting for the parts. I had already read your posts, so i asked if the problem had anything to do with the wrist pins. He said it might, but he was not the mechanic.

In addition to the wind noise and the Steering Assist problem, the small problems I had included:
- gap in the molding between the top of the windshield and the headliner,
- gap in a molding on the front edge of the front door on the passenger side,
- gas filler flap sticks out at the top and has uneven gaps top and bottom, plus it tends to stick shut so that it takes multiple pokes to open,
- the sunglasses holder in the overhead console flops down, instead of gliding down smoothly.

Before I took the car in to the dealer, I was thinking about what has often been said here at MBWorld, that MB had made a huge mistake by trying to produce a new model in a new factory (in a new country). However, this time I added to my thoughts an apprehension that MB was also introducing a new engine design (the turbo-charged four cylinder engine). Little did I know!

This was not my first MB engine to have very basic problems. I ordered my W205 C300 in 10/14, and it was delivered in early 02/15. During that wait, I discovered that the V-6 engine in my 2007 C280 is included in the range of engines subject to The Dreaded M272 Balance Shaft Gear problem. That car was delivered (in Sindelfingen) in 09/06. I had thought that cars delivered that late were outside the range of affected cars. That engine is now the problem of the poor guy that got it after I traded it in.

These problems (small as well as large, potential as well as actual) are filling the files of Consumer Reports. The resulting rows of black circles indicating "much worse" are reducing the resale value of my Mercedes (and yours). Until my C300 is sorted out, I will keep the treasured pictures of my first Mercedes in my Signature.

 

It was the wrists pins that were replaced...now i'm hearing a ticking sound after the engine is warmed up. At cold start I don't hear it so off to the dealership i go again. 😡