PROBLEM SORTED
WACKY PROBLEM FIXED
if you are at all interested read bottom part.

The Question: WHAT on earth is going on here??
The Car: 2006 Cooper Convertible non S, 78K miles.
The Equipment: Chrono pack gauges.
Driving Style: predominantly for economy since new.
The Symptoms: Coolant Temperature gauge pointing at approx 11:30 after 1-2 miles open road RELAXED driving!! On my watch 11:30 is pretty danged hot looking – I would guess about 221F if the gauge is to be believed. Graduated for 30F – 140F – 250F.
The Details (1): Coolant level is currently FULL – however several months ago I had to add a cup-o-coolant to top up every few weeks. Have not had to add any in 4 months.
The Details (2): The thermostat was replaced under warranty 31K miles ago.
The Details (3): The temp gauge does not go all the way to minimum (30F) when the car is off.
The Details (4): The temperature warning light has yet to come on.
The Situation: Funds are tight. Bringing it to a dealer has to be a last option. I am not afraid to get my hands dirty for repairs.

Thanks to HRM, ZippyNH, pilotart & Mister-Aandrew for replying and offering up good possible causes.
None of which are even remotely close as this one was definitely a weirdo.
A fly ball from left field.
The Freekin Battery Popped A Cell!!!! It was on its last legs and probably creating wacky voltages.
Say What???
Drove to the store 2.5 miles, hottest part of the day 92F, AC on MAX Heat, top down. Gauge rocketed to 2nd last graduation (approx 221F) and stayed there. Came out of store, turned the key and she started acting as if possessed – lights, gauges, relays, windows, radio all wacked out. I’m thinking exorcism and very expensive at that. Removed +ve battery terminal for 5 min – noticed the temp, as with the other gauges, now reading 0. Hmmm, interesting! Reattached – no go. The possessed like antics were freaking me out so the terminal was removed and AAA called (glad the membership was renewed last month!). Dude in the parking next spot asks if I need a jump – “Naw. Don’t think the battery the problem. Think the electronics are toast!”. AAA got there, jump started and confirmed the battery was deader than Elvis. Alternator doin just fine. Drove home with the temp gauge pointing around 194F, where it stayed until parked when it went back to 0.
Go figure. That’s one to remember for the next time.

 

Many new cars run hotter than boiling these days. You can not run a car without a radiator cap once it is at operating temps. I can't say anything about the mini directly, but it doesn't seem too hot to me as long as it stays just like that all the time.

Others with more mini experience will know better (had mine one week) but it has been this way for quite a while regarding "normal" temps.

 

It is likely low speed portion of the radiator fan has failed...allowing the temp to go higher than normal...then the still working high speed fan goes on..preventing the car from overheating(it is a single fan...run at 2 speeds....a resistor is ued to create the slower low speed portion...and this fails).
Your fan should be on continuously on low speed if the AC is on....if you hear it just cycle on and of rapidly...every few minutes...and LOUDLY...this is the problem. Aftermarket fans are avalable for $85 plus install....

https://www.northamericanmotoring.co...-solution.html

 

I am assuming that your car is not overheating at this point....and you do hear a fan?

 

Coolant temperature rapidly rising towards Red Line in first few blocks and then returning and staying Normal is an early symptom of Head Gasket failure.

 

^ true, but worst case scenario.
first, check the thermostat once again. next, check to see if you hear a fan, and when you hear the fan come on, flip on your ac. if the sound of the fan doesnt change, then your low speed fan is not working, and you will need to get that fixed.

 

HRM thanks for your input. Hi Temp problem sorted.

 

ZippyNH thanks for your input. Hi Temp problem sorted.

 

pilotart thanks for your input. Hi Temp problem sorted.

 

Mister-Aandrew thanks for your input. Hi Temp problem sorted.

 

It is always nice to learn new things.

 

Interesting....I've heard of odd things happening due to voltage issues...
I gather you did not notice a slow crank or anything until it totally failed.

 

On my 105000 miles 2004 (R50), the P/S pump is very tired and the low speed resistor of the auxiliary fan didn't ran for almost 3 years. Month ago I noticed the high speed auxiliary fan rans for 10 minutes after I turn off the motor. Last week the temperature gauge needle starts to indicate overheating after a few minutes in traffic. I see that the tranlucid coolant tank was empty so I added about a pint of tap water to fill to max level line. My Mini continue to overheat.
With the car completely cold, I unscrew the pressurized coolant filler cap and remove it. Water came from cooling tank to radiator and fill it to the top ( removing air locked) and I tighted the cap. Take a sport ride and the problem is solved.

Thanks to all who posted on this issue.