Rather than start a new thread i thought it would be ok to add a new problem with a new car to this one?
Car ran fine until changing coolant.
Now overheats.
Brand new oem fan locks on cold start then loosens off but doesnt lock when overheating.
Header tank bubbles over sometimes even before it overheats if cap is off or pressurises a lot if cap on.
Stat seems to open.
Heater blows cold.
Cylinder leakdown and coolant static tests ok, dynamic coolant test eventually goes over 7 psi once it starts overheating.
Any help appreciated and sorry to go over old ground but i am stuck, cheers.
P. S. Water pump seems ok, metal impeller as well.
You either have the mother of all airlocks or a cracked head. If you fit a static test rig it should show 5 to 7 Psi at normal temp. Heater should be the first thing to get warm. Have you checked the stat? Try back flushing heater.