This is typical Mercedes. They have a problem, and they know it. But, a recall or goodwill program costs money. Since MB has had to shuffle billions in Chrysler in the last few years, they are getting a little tired of writing cheques.
So they pretend it doesn't exist. They did it with the FSS equipped dino-oil vehicles and they'll just keep doing it. They hope the owner reaches the end of the warranty, and then flip you the bird.
Now, this is not a unique situation among car makers. They all do it. It's just that MB customers are not Corolla buyers. We're pretty smart (most of us...) and the internet has meant a communications explosion. They used to get away with it as we weren't able to share the knowledge of the problems.
Right now MB has harmonic balancer problems that they are trying to dodge. They have fuel sending unit problems they're trying to dodge. They have bad wiring harnesses they have just about managed to successfully dodge. They have just about dodged the M104 head gasket bullet. They lost the lawsuit concerning the sludge problems in dino-oil FSS cars, but will work hard to avoid paying out a red cent in claims. You'll have to prove that your engine damage is indeed covered under the terms of the suit and it's warranty program.
Dealers are part of the problem, but what else can they do? Can a service writer be honest and tell you he's done dozens of balancers lately? No. He's got "lawyer tape" wrapped around his mouth. They just go ahead and lie.
In the US, you have some consumer protection with regards to lemon laws, but even those laws can be carefully circumvented by wily makers. Many people give up the fight and just sell the offending vehicle. Mercedes couldn't care less, it seems, that they've lost a customer. Right now their attitude is that their are legions of "new" MB customers to be had, and losing a few along the way is the cost of doing business.
What has this got them? Publicity, and lots of it. Their fall from grace in reliability and satisfaction ratings has been plastered on the pages of some of the most widely read consumer and news journals. German press has been merciless to them. But, their sales continue to sail along.
But for how long? This kind of stuff catches up with makers. Ford is still on shaky financial ground thanks to quality problems, and MB's own Chrysler was nearly broke (again!) int he late 1990's thanks to their trying to dodge rotten trannies and peeling paint.
"Fool me once, shame on you, fool me twice, shame on me."
Consumers are not the fools many makers think.
1998 C230 "Black Betty"