Mercedes-Benz S63 AMG engine head bolt failure causing coolant loss and overheating on Mercedes-Benz S63 AMG

Some Mercedes-Benz S63 AMG owners report experiencing issues with head bolt failure, which can lead to coolant loss and overheating. This problem is particularly noted in models equipped with the M156 big block 6.2 liter engine, with symptoms including engine misfiring and unexplained coolant loss. Owners of vehicles manufactured up to model year 2012 may find that their cylinder head bolts are prone to breaking at the bolt head, allowing coolant to enter the combustion chamber. It is crucial to address head bolt failure promptly, as it can result in significant overheating and damage to the engine. If experiencing coolant loss and overheating, it is recommended that owners have the head bolts inspected and replaced if necessary to avoid further complications.