We have been struggling with this for 8 weeks. Had HP onsite to swap out motherboards, cannibalized another server to try all fresh parts, ilo and hp firmware upgrades, etc.
Tech support actually said 4 fans running at 68% was normal. It wasn't. HP came back onsite and tried the same thing RDamrath reported. The problem seems to be in the base BIOS. With the fan kit it seems the bios default is:
Advanced Options / Thermal Configuration / Increased Cooling
When changed to Advanced Options / Thermal Configuration / Optimal Cooling the fans dropped from 4 x 68% to
16, 16, 16, & 9% following the reboot.
I have 9 of these. Resetting the bios has worked on the 4 configured so far.