oil in water but no water in oil

[brettd1]

I've got oil in header tank about an inch of gunk not losing any water or overheating and nothing on dipstick or around oil filler cap also a massive leak around thermostat housing and oil sensor switch. Is it head gasket or thermostat housing?

[brettd1]

Thanks in advance

[noelo]

My guess
Thermostat housing.
I had same problem + leaking oil onto gearbox
Changed thermostat housing.
Problem solved