Mondeo td 2004 oil in header tank

[JA51ON W]

Hi all,I have a 2004 td mondeo and all the oil from the sump has been pumped into the header tank. Took of oil cooler and tested it,blanked off one of the water pipes and pressurised the other which led to air bubbles coming out of the oil inlet/outlet. Fitted new unit £400 for the part but on test pumped another 4 ltrs if oil into header, any ideas please, Jason.

[PaulKemp]

I would be tempted to check head gasket.
Another test would VE to by pass the cooler water feed, if oil still gets to the header it's more than likely the gasket