What's going on Mbworld. I was finally able to get my hands on a w204 c63 as I have wanted one for many, many years. To give a little back story, I purchased a 2015 c63 coupe 507 edition in May of 2024, with 73k miles (car is originally from Canada). The vehicle was well maintained with little to no issues ( other than a cracked windshield washer tank). The following mods were done to the vehicle, window tints, front under spoiler, and rear spoiler, BC racing coilvers and a resonator delete.

After purchasing the vehicle, I did the following maintenance Done at 73k:
Oil change- Using liquimoly with ceratec.
Differential service.
Brake fluid flush.
Transmission service 722.9 (blue fluid)
Air Filter

Done at 75k:
Spark plugs-NGK Plugs.
Fuel Injectors OEM

I did the following:

Rear tires
Wheel alignment
Lowered the vehicle

Both maintenance were done at known mercedes-benz shops.Both shops owners inspected the vehicle with nothing but positive things to say.

Fast forward to today, im currently at 76k miles, keep in mind being from NYC, over the past few weeks the weather has gotten tremendously cold. This morning, I started the car, let it warm up for about 10 mins before heading out, parked at the parking garage for work. At 5pm went to get the car, started like normal with no issues. I then get home, park the vehicle for about 20 minutes, upon start up I noticed right away the car did not start like how it normally would (no growl in the exhaust). The car started to then start to vibrate, idle was fluctuationing (nothing above 900-1k rpm). I then went to open the hood and started to hear somewhat of a grinding noise coming from the front left side of the engine (when standing in front of the car). I then proceeded to turn the car off and left it for a minute or two and started it again. Same issue. Now im starting to get concerned. I left the car off for a few minutes, started it back again and it started like it would normally, engine makes no noise and car idles like normal. I went to drive the vehicle, no issues driving for 30 minutes. I turned the car off and turned it back on and no issues at idle. No CEL appeared. I check engine oil constantly and also checked when this happened and engine oil level is perfect.

Any thoughts on what could possibly be the issue? I am taking the car regardless to the shop on Friday. I do not drive the car everyday, maybe once a week.

Other than this and now the rear end making some suspension squeaking, i ****ing love this car.

Sorry for the long first post lol. Ill try to post some pics also!

 

Hey, what's up man? Your Vip's friend right? Congrats on the 507!

Just speculating here, but the injectors on these cars are known to stick sometimes and dump fuel in to a cylinder. They can even hydrolock in worst case scenario. People usually recommend replacing the injectors as preventative maintenance on all the M156 engines. I still have a set sitting in the box that I hope to throw in soon. FCP Euro sells the set of 8 Bosch injectors, usually for a very reasonable price.

Not saying to go for the "parts cannon" solution here, but it's probably something you'll want to do as maintenance. Anyway, good luck man!

 

Hey whats going on bro! Yea i am, how you been? Thanks for the congrats, you know how long i have been wanting one haha. Injectors were replaced 2k miles ago so we can rule that out. Since that happened it hasn't happened back lol.

 

Likely an Intake leak or Oxygen sensors. If the car is tuned I'd just put oxygen sensors because of age / mileage (primaries only, the secondaries don't matter for fuel control on CEL and catalyst monitoring). The fact that it didn't throw a cel it doesn't really see an issue is present making me think oxygen sensors. Which is also what it uses to determine the fuel mixture and if there is an intake leak.

 

I test-drove a 2013 sedan and had the same issue. Eventually gave up on that one because of it.

 

Going to take a look around the intake and see. Car is not tuned. Thanks for the advice. Car has yet to make the noise again.