Dell had me run a BIOS diagnostic and that triggered an error when it tested the processor fan. They gave me a couple of updates to try to fix it, but they didn't work. They decided that this was enough to warrant replacing the part. That's now been done and its working normally now.
For some reason the fan on this laptop has started to run constantly. Even if you shut it down and leave it for a while when you switch it back on the fan will start running loudly not long after you log in. I did update to the latest BIOS Friday and the issue started on Saturday. I've only had the machine for a week so it is a bit concerning.
Inspiron 15 7510 fan is running loud