Hey guys,

I have new learnings. Recently I had a problem with my engine temperature always varying, after speaking to a Ford service person, I decided to replace my thermostat with a genuine Ford one, this really did fix the problem.
This was after I had done my head gasket, so I knew it wasn't gases entering the cooling system (I also made sure the whole cooling system was sealed).

I hope this may help anyone with unexplained varying temperatures.

Pete.