The most-cited buying concern, especially on the C32, is the original Valeo radiator, whose internal transmission cooler can crack and allow coolant and ATF to mix, destroying the transmission. The recommended fix is proactively swapping to the updated Behr unit; commenters note factory bulletins say not all cars are affected.
Valeo radiator failure and 'strawberry slurry of death'
Mercedes-Benz C32/C55 AMG (W203) · buying