Update: You guys are freaking amazing with your help! I had hoped that my temp issue wasn't going to involve the amount of work that it did (taking everything apart) but that appears to have solved 1 of my 2 issues. When I was cleaning out my rad I did notice some crap in the distilled water with every wash out so hopefully that was exactly the problem I had but it may have also been the thermal paste too... who knows. Just for fun I also swapped out the thermal pads (with OEM replacements). I have managed to run heaven and tested out rocket league. Temps never soared above 50 degrees on 4k ultra settings.
Here is hoping, however, that the amazing people who are following this thread and those that have already helped out can suggest a solution to my last problem (not exactly liquid cooling related though).
When all this happened and I was fiddling around physically touching my video cards etc one of my two cards (the one the monitor was not plugged into) decided to pop a code 43. This has rendered the card useless in the system at this time so I've just disabled it. Research online suggest it has something to do with static build up? One forum I read suggested removing the card and then putting it back into the system etc. When I was solving this temp issue I removed both cards and re-did the thermal applications (pads/paste) and also decided to swap them spots on my motherboard (MSI Z170 Gaming Pro Carbon). When I booted up for the first time my monitor was plugged into the code 43 card. I did manage to get a successful boot however my monitor looked very slow to respond and pixelated.
I have since disabled the card again and plugged my monitor into the known good card (that previously had temp issues) and everything is hunky dory however I'd really like to have both cards functioning. Anyone have any ideas or should I maybe post into a new thread in a different area?
Thank you all again for your assistance with my cooling issue!!
Unfortunately it sounds like the card may have been damaged. Things to test:
Use just the bad card on its own, in the same slot. (could be an SLI issue)
Use just the bad card on its own, in the other slot. (testing PCIe slot issue)
Use the good card in the bad card's slot. (confirm that the slot is good/bad)
Swap cables around! Swap the cable between the good/bad cards, try different connectors on the bad card. (test for cable/connector problem)
If the good card works in any slot, and the bad card doesn't work in any slot, well, I'm afraid you have your answer. Something with the card.