Join Date: Jun 2015
Location: Dalgety Bay, Fife
Car: Mini Cooper, MG TF, MG Midget
If the system has not been properly bled then that would be the first thing I would do, or get done.
As yet I have not done it myself but I am sure there are plenty of forum members who can give detailed advice on doing it.
There are other indicators of HGF like oil emulsification or deposits in the coolant tank, or persistent coolant loss. It is too easy for garages to blame all ills on gasket failure, although that is always a possibility.