Heater Matrix Corrosion?

Morning,
Well i bought a supposedly seized 2001 JTD 156 a week ago, turned out not to be seized but other issues. Namely oil cooler shot, radiator leaking and heater matrix u/s.
The shot oil cooler looks to have filled the collant system with oil, which is nice! I removed the heater matrix last night, and the top header were the pipes to connect to has disintegrated / corodded. Has anyone seen this before? it literally looks like it has perished?.
I have a pic but dont know how to add it?

All comments gladly received

Is this a one off?

Looks like the route of the problems have been the oil pump pressure releif sticking closed and over pressuring the oiler cooler untill it failed and filled the cooling system with oil !!

i've never seen or heard of that heater matrix issue before so i think its safe to say its a one off. i suspect the oil damaged the hoses.

Yeah the pump was pushing out a lot of pressure, by passed the oil cooler and fitted the oil filter directly but the pump was blowing the seal out. Had the car running last night with no leaks. just trying to get the oil out of the system.