Were is the coolent censor on a 99 uk turbo.

 

Screwed into the block, behind the alternator.

If you look behind tha alternator, you will see THREE sensors. One is screwed in vertically and is furthest forward. That is the oil pressure switch.
TWO are screwed in horizontally further back. One has TWO wires from it. That is the coolant sensor feeding the ecu. The other has one wire and is the sensor for the gauge.
HTH.

 

Alcazar is almost right. On MY99 onward there is only one sensor - which feeds both the ECU and gauge. As he says it is screwed into the coolant distribution main behind the alternator and power steering pump.

 

Didn't know that, mine is a 98 car, so I was going on that.