Hi All

trying to systematically work through some issues I have with my recently purchased 1992 Ford Sierra Ghia Hatchback.

It's a 2.0i DOHC EFI 8V that I bought and imported from Spain start of march and had shipped to Ireland via way of the UK.

It briefly overheated on the drive from Dublin to where I live so allowed it to cool sufficiently before getting it home.

I'm knowledgeable with cars rebuilding and modifying Volvo 855 AWD's and S70 T5's are my drug of choice.

However, this simpler motor has me scratching my head.

Whenever I get a car I do a full stage zero service - replacing all parts that will likely go wrong such as water pump, alternator, belts, thermostat, thermostat housing, coolant, oil, oil filter, pollen filter, fuel filter to name a few things.

I've flushed the entire system, thoroughly, disconnected all coolant pipes, even descaled the engine block, heater matrix, radiator system and the car initially went from blowing hot/cold to hot when running the internal cabin heater at hot.

The over pressurization is now back and the initial hot to cold to hot issue is back and I've noticed that the coolant is being pushed through the expansion tank cap.

There is no water-oil mixing going on and head gasket sniff test is not showing a damaged/leaking gasket.

totally baffled by this so anyone experience the same issue?