We bought a 2015 C300 from the Mercedes Dealership in Manchester NH. The piston cracked at around 80,000 miles. They quoted $14,000 to repair it. Many people have had this problem with these cars, but after having the service manage not return our call and then the general manager not respond to an email, we called corporate. They stated this was not a "known problem" with these cars. The lady said if it was a known problem, they would be hearing from their dealers about it and would then fix it under warranty. I asked if the dealer reported the problem with our car and she stated that they had not. I asked if she thought that pistons should be cracking at 40, 60 or 80,000 miles and she said she was not a "technical person". I answered for her - they should not be cracking.

I've owned 4 Mercedes not including this car which was actually bought by my son. I told her I have bought my last. I would avoid this dealership if at all possible, avoid Mercedes as a whole and DEFINITELY DO NOT BUY A 2015 C300 UNLESS YOU KNOW THE ENGINE HAS BEEN FIXED OR YOU HAVE A GOOD EXTENDED WARRANTY!

The model year 2015, C300 with the W205 engine that had under 3500 miles, yet serviced by the MB dealer regularly, had a major engine failure. Quote from the dealership email: "Replacement of all connecting rods, pistons and rod bearings is necessary to rectify the problem." Warranty on this car was over... The repairs would take about 5-7 work days. Total is $10,400.00 + tax.

I called the MB USA and they contacted the dealership and the two of them came to an agreement that they will foot the half of the bill, so instead of the quoted $10,400.00 +tax, I did pay $5,137.00.

I need to mention that in spite of the low mileage, the oil and the coolant were changed seven times (by the MB dealership service department) beside the transmission fluid two times and the differential oil as well. So the car was serviced better than most (if not all) cars in this country with this mileage.

I never did like this car. My wife, for whom I did buy it, hates it and refuses to drive it. It also has a rough ride, (run-flat tires). I have had MB cars since 1975. This car - setting aside the engine failure - is truly the worst, least comfortable car among all that I had. I did figure that the small, high pressure engine would not last too long because the alloys are not going to be upgraded to the required level, but of course I never thought that 3,500 miles is the limit. I shall mention too that I do not think that the car has reached 80 MPH for a single second, thus never been driven hard at all.

I understand that I am especially ill-fated and others have better luck with their similar model.

Nevertheless, I do not recommend the W205 engine type and be aware that you will find this type of motor in many other MB vehicles including SUVs as well.