Many garages are still failing to replace head bolts, risking engine damage and failiure.
Workshops are advised to always replace head bolts after removal, BG Automotive has said.
A BG Automoive spokesperson said: “The majority of head bolts are ‘torque to yield’, which means that during the original tightening process, they are stretched past the elastic phase of the metal into the plastic phase.
“This is where the bolt will offer the best resistance to fatigue in high frequency and high load situations.
“This results in the highest clamping and even sealing to head.
“As a part of this process, the bolts become permanently elongated.
“If they are re-used and tightened to yield again they will become weak and potentially snap
during or after installation.
“They are designed as single use items.”
BG Automotive stock a large range of head bolts for all of their head gaskets to make sure any can be carried out by automotive technicians correctly and confidently, covering over 18,000 different vehicles.
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