Pressure Testing is a common procedure when reconditioning cylinder heads.  Best suited for alloy applications however cast iron can also be pressure tested.  This procedure detects pinholes, porosity, cracks and other obscure faults within the casting.  It's also useful for checking the integrity of injector sleeves in diesel cylinder heads.

During a routine pressure test a problem is revealed under the valve seat of a Mitsubishi cylinder head. The valve seat is removed to reveal a pin hole.

A pin hole is detected within the exhaust port of a Daewoo cylinder head.