I havent' been able to find anyone that knows this, has anyone had a hard drie fail and they knw for a fact it was heat related? Does it slowly die or is it just one day it doesn't work anymore, or does it stop spinning one day and just sort of lock up?
Heat can cause data corruption at best or death at worst.
Some drive, older model especially had what was called thermal calibration. the hdd itself would calibrate the head/platters position to compensate for material variation due to heat. Modern hdd dont do this anymore, as this cannot be a good thing when you need to capture video or play streamed files.. the drive simply cannot just stop sending or retriving data to calibrate itself then resume.. it has to work all the time. Back in time, the first drive without calibration were advertised as video capable hdd..
Today, with better mechanism and electronic, hdd can operate much more stable in various environnement than older hdd. But running them in extreme environnement would cause them to fail eventually. first, when they get hot, electronic part become less reliable and more prone to errors, which will cause data corruption. At first level, drive software can correct those errors but if temp keep increasing then even the hdd wont be able to made the simple correction. Then, if they are not cooled, material expansion can cause misalignement and create more errors.. And since you are creating errors, then the electronic work harder to try to correct the, creating more heat.
At the extreme, the drive may crash. Not the head, but the electronic. Normally, a computer reset will have the hdd to restart, but repetitive crash due to heat will make the hdd to fail for good.
you should leave at minimum at least half an inch of clearance between hdds and the next up or down obstacle