I purchased a new 2014 c250 coupe (18 miles on the car) in 12/2014. I've had quite a few issues and have made over 12 visits to the dealership since the second week after purchase.

First: the car has smelled like coolant and gas since I first parked or in my driveway. Each time I've gone to the dealership for this issue, they smelled nothing and found nothing.

Second: I've taken it in several times for a squeaking noise and the dealership couldn't recreate the noise. I decided to Google to see if other Mercedes owners experienced the same issue and discovered the culprit was the parking brake. I took it back to the dealership and mentioned I found information regarding the parking brake...they repaired it; however, I took it in last week for the same noise again.

Third: the third week after purchase, the trunk hinge cover broke and had to be replaced.

Fourth: the sunroof sticks, stops, squeaks and gets out of sync. I've taken in several times for that and have to take it in again last week for the same issue.

Fifth: the windows periodically squeak. I've taken it in several times for that.

Sixth: the check engine light has come on twice and the car went into limp home mode, both times in traffic. The car had to be towed to the dealership the first time and the secure advise said it was a false code...they updated the codes. The second time it happened, I was driving 500 miles to visit family for thanksgiving at 2 am in the morning.

Seventh: when I started my car to make the return drive home, none of the commands on the steering wheel worked, not even the horn, which would have come in handy when an 18 wheeler and a car drove into my lane.

Eighth: I smelled coolant again and my brother opened the hood to find dried coolant on the reservoir cap and engine.

The car has been at the dealership for a week now. The service advisor said he's never heard of this many issues with one car in his 20 years of experience.

This is my first Mercedes and I'm not sure what step to take next.

 

Wow, what a drag... You may want to find another dealership.

1. It sounds like either the rad. cap needs to be replaced or there's a leak elsewhere.
2. Does the emergency brake release lever drag a bit when pulled? It appears that I may have the same culprit (I'm still looking into this issue).
3. Can't help you here on the trunk hinge cover unless you had the trunk full of stuff and something hit it when you closed the hatch.
4. My sunroof would open very slowly upon purchase so the dealership simply cleaned and re-lubed the tracks. All better now...
5. Perhaps the circuit that lowers the windows slightly when closing the doors may need attention. It sound like they don't fully close once the door is shut. Try hitting the window regulator switch while driving and listen for any slight motion.
6. Never happened to me but I've read that sometimes the Check Engine light will illuminate if the accelerator is aggressively depressed.
7. Did you pull over, stop the car and restart the ignition to reset the CPU or did you find a greater problem? This hasn't happened to me yet.
8. See #1 response.

They mostly sound like small issues however; I would be pretty upset, especially if a second trip to the dealer was required. Good luck with the car.

 

Thank you for the reply. I contacted MBUSA who had a regional customer care person contact me. The regional engineering division worked with the dealership to repair the car.

Items 1, 6-8: No one told me to stop and restart the car. I'm not repair savvy, so I'm not aware of what a CPU is. Thanks again for those tips. Yes, it always occurred after was in the process of accelerating.

They said the engine was misfiring, so they replaced all spark plugs. They also said they modified the turbo because there was condensation in it, which may have caused the release of coolant.

2 & 5 They said they couldn't recreate these issues; however, I've never used the emergency brake. The first time it happened, they said there was a bulletin about emergency brake issues, so they replaced it.

3. There was nothing the trunk, so apparently, the hinge cover just mysteriously broke.

They replaced the steering unit and control module also.

I've been to the dealership about 12 times in my 11 months of ownership. I previously had a Camry and never experienced issues. It's weird how they explain away the recurring issues like it's the norm for this type of car.

 

Sorry, the CPU is the car's main computer. Sometimes restarting the car may reset it or you have to disconnect the battery's positive lead for a few moments.

I hope you're car is all better now...

 

Why thank you! I picked it up yesterday. It drives differently now since they've modified the turbo. Fingers crossed that there are no more problems. It's ridiculously annoying to have this many issues with a new car. They said they're confident they've resolved the problem, but if it happens again, they'll replace the car.

 

I fail to see how coolant and the turbo could have been related in any way. I've never even heard of condensation on a turbo. They can get oil in them but they get so hot any condensation would evaporate off.

 

Hmmm...I wonder why they'd give me erroneous information? The repair invoice states "misfiring of cylinder 1. Remove all plugs. All plugs are very carbon. Reliever all plugs. Opened tech case with MB then modified intercooler."

They replaced the steering unit and module. They saw the dried coolant, said they tested the system and couldn't duplicate the issue. For every other concern I had, they stated they couldn't duplicate the issues (squeaking wheels, intermittently inoperable sunroof, windows intermittently squeak when opening/closing, coolant smell, gas smell, car sometimes doesn't seem to want to change gears when decelerating from high speed).