Using new head bolts when performing a cylinder head installation is always a good idea however, on late-model engines that came from the factory with TTY (torque-to yield) head bolts, replacement is an absolute necessity. TTY bolts are designed to exert the maximum clamping force for a tight head gasket seal, however they permanently stretched and could fail if re-used.

• Choosing Victor Reinz assures getting OE quality parts in gaskets sets that have the coverage, contents, packaging and electronic cataloging to best meet the needs of the aftermarket.
• Head bolt replacement recommended.
• Torque-to-yield bolts are designed so that they can be elongated beyond their elastic limit into the plastic region without problems.
• When a specific tightening torque has been reached, the bolts are turned further through a defined angle, which pre-loads them into the plastic region. Consequently, no retorquing is necessary.