A 3 yr old Xtype  2.0d Classic. ( 27K miles)
Great motor, but it takes about 4 miles before the temp gauge  registers
anything, and even on the motorway the needle moves around in the lower half
of the dial.
I reason that the sensor might be located in the rad header tank,( unusual)
my gauge might be faulty, or more likely my engine coolant thermostat could
be stuck half open.
Two garages  have shrugged it off, saying that diesels always warm up
slowly, so it is not unusual.
Any words of wisdom from those who should know?

Thanks
P