TresX

I usually keep cars a good while…thinking this one will have to go by the last year of cpo….

M274 failure

teksurv

How many miles/kms do you have on the car? There have been reports of piston cracking on this engine, and it has been discussed in this and other sections of the forum. That said, the percentage of failures is still relatively low. My wife's 10 year old SLK with the 3.5 M276 so far does not have any of the known issues for that engine. It's a roll of the dice.

W205C43PFL

M276 is one of MB's most reliable engines so I am not surprised there are no issues with the M276 in the SLK, M274 is the one that has piston cracking issues but like you said it is rare.