Grey Screen - Error help needed

Hi All,

First post here as most of previous question have been answered by threads already posted.

I have an iMac 27" Intel i5 with 8Gb RAM 1Tb HDD and it has been very slow over the past few months often freezing and requiring a hard reboot. The machine has been getting very hot as well.

Yesterday the machine froze twice in quick succession and the second time it failed to reboot and gets stuck on the apple logo with the spinning wheel. I followed the Apple support

1. SMC reset [4]. No difference
2. PRAM reset [5]. No difference
3. Safe boot [6]. No difference
4. Hardware test [7]. - no difference
5. Boot from install disk. - disk keeps getting spat out​

To get more info I did step 3 again in verbose mode and the end of the CMD lines look like this: (# just indicated new line just incase it wraps in your screen)

# AppleAHCIDiskQueueManager::setPowerState(0xffffff8019b6900, 2 -> 1) timed out after 101079MS
# disk0s2: I/O error
# 0 [level 3] [ReadUID 0] [Facility com.apple.system.fs] [ErrType IO] [ErrNo 5] [IOType Read] [PBlkNum 1534624] [LBlkNum 1534624] [FSlogMsgID 2056997970] [FSlogMsgOrder First]
# 0 [Level 3] [ReadUID 0] [Facility com.apple.system.fs] [FSlogMsgID 2056997970] [FSlogMsgOrder First]
# jnl : unknown-dev : update_fs_block : error reading fs block # 1534624! (ret 5)

Can anyone help identify the issue from this or is more needed?

PS - Even though the Mac is doing nothing with the CMD line stuck it is still getting very hot! I have checked and cleaned the fan/ vents so this is not the issue unless the fan has actually stopped.

The iMac is out of warranty.

Thank you for any help.

Sav