I'll l grant you the Intell Core 2 Duo T7700 processor in that iMac was also used in Apple's LATER MacBook Pro laptop, but the iMac's logic board, fans, speaker system, optical drive system, power supply, graphics board were NOT THE SAME as were installed inside that far lower powered MacBook Pro which for most things would be clocked slower to conserve battery life something totally unnecessary on an iMac . . . and that MacBook Pro retailed for a starting price of $2799 compared to $1199 for your iMac.
That iMac had THREE cooling fans counting the one on the processor, a fact you seem to be totall ignorant of. Oh, wait, make that four. . . Forgot the fan in the internal switching power supply.
This is the internals of a 15" MacBook Pro:
I've maintained well over 120 Macs and iMacs over the past 18 years in my office and had only ONE hard drive failure and it was not due to heat. You do not have a clue what you are talking about!
Essentially, Apple is NOT going to put the componrnts of a $2800 laptop into a $1200 desktop, because that's what was being claimed!
Later, when Apple wanted to make an entry level iMac, they did indeed offer a low end intro model iMac with an M Class Intel processor, the same as they put in the MacBook Air, with low end specs, which they could sell for under $1000. It's essentially a Mac mini with a built in screen. However, it is not representative of the entire iMac line, as was being implied.
https://www.macupdate.com/app/mac/23049/smcfancontrol
The hard drive died from heat. Before it went completely dead it would work when the computer was cold and then stop when it heated up enough. Afterwards I found this freeware which lets you override the default fan settings, it kept the replacement drive alive. I think part of the problem is I used it for gaming and that made it hotter than most iMacs which never get used for that.