Coolant leak

[Etothel]

I’ve had an issue with losing coolant in my 2012 d22 I’m trying to get a replacement gasket bc I can see it has corroded but nowhere can seems to have it could some one help me with an accurate description of what I’m looking for and also let me know if it’s just the seal issue or it’s caused by too much pressure etc tia I think it’s the thermostat housing maybe but have also been told egr to manifold gasket cheers