1million mile isx15 never been touched - what now?

[tree98]

Infame it..... a million miles is really all you should ask out of an ISX or you risk catastrophic damage.

BUT it must be rebuilt properly. All OEM internals no aftermarket, the counterbores absolutely have to be cut and the liners shimmed up to .014

the head must be replaced with brand new OEM not a reworked or rebuilt one. It also must be torqued down properly by doing the initial torque and then letting it sit overnight for the gasket to crush and then doing final torque.

All the proper steps are in Rawze's rebuild series on YouTube.

I'm curious if this engine is still mandated or has it been tuned? I'm also curious if anyone has ever rebuilt the high pressure fuel pump? Those have to be rebuilt every 400k miles or you risk complete engine destroying damage, we're talkin boat anchor type stuff.