xserve CPU B, very high temperature

We have an xserve in a small server room reporting a very high temperature for CPU B. CPU usage is quite low.

CPU A is at 88° but CPU B is at 261°.

All blowers are between 12k and 16k, which seems high.

right inlet is 72°

left inlet is 77°

PS1 exhaust is 108°

PS2 exhaust is 126°

What is this most likely attributed to?

Thanks!