replacement temp gauge
 

My temp gauge in my car has become very unreliable, which is very unnerving. Fan come on when the needle hits the solid section and turns off when it gets to the third mark. When we checked it with an IR temp gauge at the local Porsche mechanic it came on at 90c anf at 82c which I was told is normal.
What I want to do is put an extra 2in VDO temp gauge where the clock is in the centre console. What I need to know is what size is the sender it is either 14mm or 16mm.