Hi I bought a 2002 mk5 fiesta tdci , it seems due to an overheat it had blown its top coolent hose off but otherwise seemed ok so I took a chance ,so far I have given it a new thermostat housing and coolent sensor / coolent flush . I drove it for 5 miles today and still not good . It has that useless dash that just has an arrow on norm but no idea of temperature so I accessed the hidden menu and it slowly went to 8c and went no higher but arrow moved up to 3/4 way mark on vague gauge they fitted ,the thermostat had long since opened after the 5 mile trip as  top and bottom hoses were very hot / I’m thinking I’ve a flow problem , getting good heat and cold in cabin , fan not cutting in and no idea how high the temp got!! But was hot under that bonnet after that short run . I’m fitting a new heater control valve tomorrow and  another fill of coolent but I’m not holding out much hope , there’s some evidence the timing kit and pump was done less than 20k miles ago but still coming to conclusion the water pump is probably knackered but why the Ecu thinks the car got no hotter than 8 deg c is also a mystery and tried 2 sensors before bought that new one all doing the same thing !!no real loss of coolent evident either  if somebody has ideas I’d be very grateful , thanks 

i do recall a thread on here a couple of years ago where someone fitted a new (cheap) water pump, pretty soon had overheating problems, turned out the impeller had broken off the water pump shaft. Trouble is it's not easy to check that. Even spinning the pulley to try to judge that needs the timing belt taking off the pulley

Hi isetta thanks for that yes think I’m coming to that conclusion , I ran through the hidden menu and I’m taking it the coolent temp is the one with number and c at end (as it is in my focus petrol )it only reached 8 c on gauge and stayed there even after getting proper hot could lack of flow cause this bad reading ? Gauge was higher end of norm on dash so obviously the ecu gets its temp from somewhere other than temp gauge , hoping fitting the heater control valve tomorrow improves things but if not I suppose pumps all that’s left ☹️

Went to replace heater control valve today and found this on outside of bulkhead / no heater control valve , wish I read my messages before I started 🙈(thanks dan62) hope this saves someone else the hassle as wipers were welded on , 2002 on tdci no heater control valve it seems