My 2016 c450 AMG just went into the Mercedes Dealership. They have responded with their findings which included a detailed verbal and video description.

The video shows corrosion and cracks along the subframe on both sides. The service report states, "completely broken right-side rear subframe and the left side is also showing signs of imminent failure".

Additionally, they are recommending the following:
Repair or replacement of the rear subframe.
Repair or replacement of the rear flex disc due to large tears.
Reseal of the transfer case to address oil leaks.
Replacement of the pinion oil seal to address oil leak.
Reseal of the upper timing case to address oil leak.
Replacement of the transmission oil pan gasket and transmission service.
Reseal of the cam covers to address oil leaks.

I have been advised by my service rep that the 2016 C450 is not covered by the recall or warranty.

NEED HELP AND SUGGESTIONS

IDK what would cause that. Maybe ocean (salt) flood water? Maybe a poorly repaired rear end collision? Sorry to hear about that situation, I don't have any advice on how best to proceed.

There is a recall for subframe for W204 and older MBs but I don't think it affects our W205, no?

OP didn't indicate his location, but I grew up in the northeast where salted roads in the winter would destroy a car in 6 years. Best solution is to buy a junker to drive during salt season and keep the lux car stored.

^^^^This^^^^
I was gonna sell my 2013 Sonata that has 60k miles on it when I got my c43. They wanted like 5k for it... Pshh now its my winter beater. Chicago weather is brutal.
That sucks with all the oil leaks. I think they are well known for our cars. Go to a reputable euro mechanic and get it all serviced if you want it to last.

Estimate for all the work from Mercedes shop came out to $16K! Going to reach out to representative of Mercedes North America.

I do live in the DC area so salt could be a factor but still think it should be covered as a defect.

A subframe itself is not expensive (600plus). Save yourself at least half on the labor at an Indy. The dc area gets lots of brine which is very sticky and regular undercarriage washes are needed. For long term performance consider fluid film or the like. One of my vehicles is an 06 and still minty fresh underneath due to fluid film. That vehicle is known for rust. If you want to undertake protecting a frame, lmk.

I found a fantastic new independent in the Westminster Md area if you are interested…though not cheap, but cheaper than a dealer. Lmk

or if you are closer to modern masters, hit them up

Appreciate the feedback! Can you send details for the independent in Westminster?

Still might try the route through Mercedes North America but i know that's a longshot.

Mercedes specialists. Tell them Gary with the wagon that was recently there recommended them. I uh…erased my transmission and clutch coding with a launch creader (i’ll have a thread on that ) and they got me going again for a very inexpensive price of one hour labor. YMMV.