Sounds like you either have no thermostat, or it's jammed. Directly below the oil filler cap you should see the Rad top hose(looks twisted). It travels from the top of the rad to a solid plastic block with a jubille clip.
Using mole grips, remove the jubille clip. Do this only when the engine is cold. Then look inside connecting block, you'll see thermostat. Poke out with a thin screwdriver, replace thermostat and reverse procedure. This is the likely cause, and it's the cheapest. Other causes could be, temp control knob not actually turning metal rod behind it, dodgy heater matrix or a jam somewhere further down from the temp control dial.
Finally if it was the heater matrix, most of the time you'd notice a very slight wet patch coming from behind the centre cowling, just in front of the gearstick.
robboWVH, April 2008
