this concern with updated Viton o-ring washers fixing the issue. With the new HPO system design also came a Snap To Connect (STC) fitting. Some models had issue with the prongs of the STC fitting breaking causing the fitting to lose its sealing property and again, a no start condition for the engine. Another frequent (but not always catastrophic) issue with the HPO system is the Injection Pressure Regulator (IPR) screen. The IPR screen is located in the engine valley with the oil cooler. The material used was susceptible to failure and neglecting to replace the screen during an oil cooler replacement could lead to the debris being sent through the HPOP causing complete failure. If the HPOP does not fail another common failure point is the IPR that, if contaminated by debris, will not be able to seal completely and will then "bleed off" oil pressure causing a no start condition. - Ford/International used four Torque to Yield (TTY) cylinder head bolts per cylinder for the 6.0s and 6.4s. TTY bolts offer some of the most precise clamping force available but can be problematic. In certain situations (Oil cooler/EGR cooler failure, high boost/load levels brought on by performance upgrades) TTY bolts can be stretched beyond their torque mark by increased cylinder pressures (commonly from coolant being introduced into the cylinder). This has never been addressed by Ford due to the fact that other malfunctions or abuse must occur to stretch the bolts. Some in the aftermarket will replace the factory bolts with head studs in an attempt to protect the head gaskets from future failure. If this is done without addressing the underlying issue, the head gaskets may fail again bringing along a cracked or warped cylinder head. In contrast, the Powerstroke 7.3s and 6.7s have 6 head bolts per cylinder while the 6.0, VT365, IDI 7.3s and 6.4s only have four. Electrical and fuel Numerous PCM recalibrations, attempts to "detune" the engine, fuel injector stiction (caused by lack of maintenance and proper oil changes) along with several other driveability and quality control problems have plagued the 6.0. The FICM (fuel injection control module) has been a problem, where low voltage in the vehicle's electrical system due to failing batteries or a low-output alternator can cause damage to the FICM. In addition, the placement of the FICM on top of the engine subjects it to varying and extreme temperatures