finally completed reading all posts in this thread ... here is what i percieve
-- somewhere there was a mention of gas pressure release in early morning radiator cap opening ... plus no water coming or going to reservoir ...... could it be an airlock a choke ... air-blocks cause heating up
--- water level remains the same, right ? ... if yes ... head gasket or cylinder cracks can be ruled out
radiator cleaned ... no leakage ... fan is working ... the items which can still cause heating up :
-- a fan whose blades have bent (happens with heat and usage) or reduced in size ... simple solution is to put a new fan but first get this one checked
--- fan speed reduced .. it has a motor, a resistance which wear with time
--- shroud issue ... the canopy which directs all air to radiator has a problem, like broken .. in correctly fit
--- faulty guage or loose guage wires ... needle going slightly above half is quite normal in some vehicles ... so u need to be clear what is a temp rise i,e a normal or an abnormal where if not countered the needle keeps climbing up to red zone
-- in correct timing or valve clearance ... other valve faults also raise temp
-- poor oil condition or low oil level -- u already have a tapid head leakage, do u frequently check oil level
-- poor lubrication ... could be a number of reasons
khyber and mehran have identical fuel sending unit (the item that senses temperature in engine ) but if u put one in another (exact sequence not known) it gives a false reading
conclusion
-- be sure that the temp is really rising and engine is heating
-- check all what has not been checked so far
