A bolt is just a bolt – nothing could be further from the truth! Todays gaskets need exact defined clamp forces to work properly. This parameter is 100% controlled by modern stretch bolts for all engines. Individual development makes sure that bolt, gasket, and engine parts are one reliable unit. These types of head bolts increase in length after assembling and tightening. Elring® recommends to change the bolts together with the gasket and to follow the instructions after any service.