"Wasserboxer", abbreviated as WBX, is a German compound noun where "wasser" indicates that the engine is water-cooled, and "boxer" describes the arrangement and movement of the pistons.

[1] As in Volkswagen's earlier air-cooled luftboxer engines, the wasserboxer's three-bearing camshaft is driven directly from the crankshaft by means of a small steel gear on the crankshaft and a larger aluminium gear on the camshaft, with the whole mechanism internal to the engine.

[1] The wasserboxer also features a "Heron cylinder head" with "bowl-in-piston" type combustion chambers, in which combustion takes place within the piston area rather than a recess machined into the cylinder head.

[1] The cylinder banks consist of cast iron cylinder liners inserted into the crankcase surrounded by a water jacket, with a "rubber lip" style water jacket seal.

Some design decisions, such as poorly placed sensors and a cooling system prone to leaks, may have made the engines more likely to experience this type of failure.