The M156 AMG engine is known for factory head bolt failure. These head bolts assist the head gasket in keeping the flowing oil, coolant, and air charge in the cylinders separate from each other. Unfortunately, the factory head bolts are installed “torque to yield”, meaning they are tightened down to the point where they consistently and permanently stretch. This in conjuction with a design flaw causes the M156 Factory headbolts to commonly snap, causing the head to lift, mixing fluids, and causing severe damage to engine internals.
In order to combat this issue for good, we have produced H-13 Head studs to replace the flawed factory head bolts. While most aftermarket head studs on available are made of mild steel, we constructed ours of H-13 steel making them the strongest and hardest head studs on the market!