2010 skoda Octavia 1.9tdi

224k miles

car overheating when travelling up hills and heaters only warm when I reach 2500 revs anyone have any idea 

changed the following

radiador

water pump

thermostat

flushed engine 

 

At that sort of mileage, you may have a radiator hose softening/collapsing and causing a blockage. Give all the hoses a squeeze and see if any feel noticably softer than the rest.

Head is ok had test today 

must be some kind of blockage somewhere never using k-seal again