ARP Head Studs Loosening on Exhaust Side - Loctite and Re-Torque Fix

Engineintermediate✓ Community Verified

Problem

ARP head studs losing torque after installation, particularly on the exhaust side of the 7M engine. Studs that were originally torqued to spec (85-90 ft-lbs) were found significantly loose after a few hundred miles of driving.

ARP head studs found loose below original torque specExhaust side studs more affected than intake sideLoosening occurs within a few hundred miles of installationCan lead to head gasket failure on exhaust side if not addressed

Root Cause

Thermal expansion and compression cycling causes yielding of the head gasket and the aluminum head surface around the stud holes (visible as indentations from the head gasket). This allows the clamping force to relax over time, especially on the hotter exhaust side. Additionally, studs installed without thread sealant on the block side can work loose from the block threads.

Confidence

Moderate confidence — Multiple community members agreed on this solution

View Original Thread →Posted March 2005 on SupraForums.com