First off, Andy posted this picture awhile ago to show the location of his temp. sender. I am trying to determine if I could use the OEM air purge screw location with a metric adaptor from PEGASUS auto racing to mount my temp sender there.

 

Does anyone know the part number/cost of the plastic radiator hose coupling with the air bleed screw in it?
It's in the picture just in front of the intercooler.

 

The coupling in question is called a Breather Tube
MINI / BMW part number = 1 17-12-7-515-502, List $4.68, Net $4.25
The thread size for the Bleed screw is 1/8 27 NTP

All that is required to use this as a location for a water temp. sensor ( mine is a 1/8 27 NTP ) is to run a Tap of that size down the threads to ream out a lip at the bottom.
Installation only requires cutting a 17mm section out of the top hose and installing Breather tube coupling in the hose with clamps.
This is very similar to what Andy used for his temp.sensor. This is available at any dealer although they may have to order it.This mod with the OEM part only introduces brass ( temp. sensor ) into the cooling system. I haven't replace an OEM one but I believe they are probably brass also.
This will make for a clean trouble free installation.

 

you will have to add a ground wire to the threads if the sensor is the electric type

 

Thanks for the tip, I've got that covered. Check out Andys color code on that thumb nail picture I borrowed. Blue for water temp. signal, Black for ground = Logical

Please READ, trying to add a second breather tube in the radiator hose by cutting into the hose to add it will not work.
You could sacrifice the bleed screw for a temp. sensor in it's place, this might make it hard to bleed air out of the cooling system though.

The radiator hose has a larger molded end where the OEM breather tube goes into it.
The inside diameter is to small in the rest of the hose to go over the ends of a second breather tube.
Oh well, time to make one that will fit.