[The Radium King]

if your car is still running then methinks not an ims/rms issue. you have 'intermix' (you can search the forums on this) - a mix of oil and coolant (ims causes intermix by shoving connecting rods through cylinder walls, etc., so not your issue). the oil cooler was a good place to start looking as there is opportunity for oil and coolant to get together if a seal goes bad. as this has not fixed your problem (or perhaps new unit was also bad, or perhaps faulty installation?) that you might have a bad head gasket.

edit: ... or a cracked head or block ...