Ok guys I'm beyond lost on what to do or what's happening and slowly running out of dollar.

Quick history took car in for auxiliary water pump replacement, got car back noticed fan staying on. Took it back they bled it, still no difference. Finally took it back tech says it's thermostat housing leaking from pressure test.

Bought new thermostat housing, replaced it myself. Bled it few times fan still staying on.

Checked bottom radiator hose and noticed it's cool to cold to touch. I feel pressure in it.

I get hot air in the cabin.

The temperature is sitting around 108c then if I open the taps I see the temperature drop to 95c. Also if I turn the blower in it drops.

I'm praying it's not the water pump.

I've read in a vw forum of a similar matter that needed the ECM reprogramming from dealership.

Anyone able to shed light on this

 

When I installed a coolant temp gauge, I put it in the bottom hose. Never did get a legitimate temp reading! Turns out the Mini has a "reserve" coolant source that activates when engine coolant reaches about 235 deg F. The bottom hose you reference is in this "reserve" source. Found another hose that was hot after driving awhile, and put the sensor there. Works fine now.

I realize this is no help for the rest of your issues, but hopefully, you'll have a little less to worry about now. Best of luck ---

 

Maybe the fan relay is stuck...

 

On 4th Feb 2013 robbo mcs wrote an excellent post on this forum explaining the symptoms of thermostat/temp sensor mismatch.

It certainly explained my fan-running problems and I think it's probably the best-explained and most-relevant post, IMO, on NAM; certainly for me...

Do a search and see if it is helpful in your case, too.

(It was called 'Does your JCW's engine fan run after turning off the car?')

 

Thanks so much for that link it was a great eye opener to these dodgy thermostats that seem to be running at 108 instead of 104-105 and causing mayham with ecm.

I spoke to the Guru himself and his shared some more info that the auxiliary water pump is linked to the cat convertor and due to the removal of cat on his he suspects that might be keeping fan on.

Which brings me back to my initial conclusion that the problem of fan on only started after the new auxiliary pump was replaced.

Now I know my post cat o2 sensor is dodgy and I wonder if that's what's throwing a dodgy signal to the ECM as the wiring seems to go past the aux pump, up to the thermostat and on to ecm.

Long shot but Il try and replace it tomorrow.

 

Just an update they replaced the original aux
pump and fan is working fine again don't know
why. They have have sent a msg to bmw hq
with the issue and awaiting response.

 

A welcome update - and a great result!