Temperature issues

[Lone Star]

I was off today and decided what a glorious day to take her out for a spin. Now it has to be said that todays temperature was approximately high 20's/ low 30's. For that reason i thought it was reasonable to put on the a/c. Whilst the a/c works ( and works quite well! ). I found it disturbing that the engine water temperature started to creep up to 117 degrees. Please bear in mind that at this point I was hovering between 4th and 5th gear doing 70 mph on the motorway. I immediately switched off the a/c and had both windows down instead. Within a few minutes the water temperature started to drop to around 100 degrees.
Now my first question is: Do I have a/c that is not fit for purpose? I.E. everytime I go to use it, the water temperature goes through the roof and becomes unusable. Was I panicking for no reason and 117 degrees is ok!! Or do I have a problem. And if so, what needs to be done to sort this issue?

The next problem I encountered today was I noticed the oil temperature when after going for a vigorous run. Crept up to 100 degrees when stationary. Surely this can't be right! It soon dropped to high 80's/ low 90's once I started to move again.

And finally on two separate occasions whilst on this same drive today. On my display panel it informed me that the 'water temperature sensor' had failed. I know that can't be correct because throughout the whole journey I was keeping a close eye on just that. And at no point was I unaware of what the temperatures was.

One final thought. Could all three problems be related in some way?

Cheers John

Edited by Lone Star on Wednesday 24th August 17:51

[Lone Star]

Further to my original message. I have now checked the coolant and it all appears to be there. I deliberately ran the car with the a/c on and waited.
The first fan kicked in at 83 degrees and the second fan at 93 degrees. This time however the water temperature sensor fail message did not happen! I kept the car running for 20 minutes. My first fan stayed on constantly (once 83 degrees was reached). And when it got to 93 degrees. The second fan stayed on most of the time. I guess if instead I took her out for a run. The airflow would have helped cool her down and the second fan, perhaps would not have been on as much.
My findings this time doesn't explain what happened to me yesterday. Thanks guys for your input though. I can't help but feel this problem will come back and bite me on the bum when I least want or need it!!!!